Disease Penetrance Research Articles

P429 Patient skeletal muscle area and postoperative clinical recurrence in Crohn’s disease: a retrospective study

Abstract Background Sarcopenia, a reduction in muscle mass and function, is a poorly recognised phenomenon in Crohn’s disease (CD) despite occurring in 16%-68% of CD patients [1-5]. It has been linked to both an increased need for surgery and increased risk of postoperative complications. However, the role of sarcopenia in CD and its long-term impact on surgical outcomes are unknown. We aimed to assess the link between sarcopenia and postoperative clinical recurrence. Methods Retrospective data was collected between 2015 and 2021 from CD patients who had undergone gastrointestinal surgery and a MR or CT scan within 3 months prior to surgery. Follow up data was retrospectively collected for 6 months. MR and CT scans were used to determine skeletal muscle area (SMA) from the cross-sectional L3 vertebrae, which was used to identify patients as sarcopenic or not. Clinical recurrence was defined as a Harvey-Bradshaw Index of 5 or more. Statistical analysis included demographics and inferential analyses. Missing data was attributed to the absence in clinic notes. Results This single centre study included 64 CD patients [56.3% male, median age of 30.0 (18.0-76.0), 87.7% non-smokers] who had undergone gastrointestinal surgery. Most patients had ileocolonic CD (74.6%, 47/63) and either stricturing (46.9%, 30/64) or penetrating (31.3%, 20/64) disease behaviour, and 23.4% (15/64) had perianal disease. 45.3% (29/64) of patients had had at least one previous surgery. Preoperatively, 20.6% (13/63) of patients were on steroids and 55.6% (35/63) were on combined drug therapy. Patient median SMA was 113.6 (61.8 – 281.7) cm2 with sarcopenia found in 74.1% (43/58) of patients. SMA was lower in females (females: 92.1±19.3 cm2 vs males: 137±39.5 cm2, p<0.001) and patients with a BMI<18.5 kg/m2 (BMI<18.5 kg/m2: 91.8±19.1 cm2 vs BMI≥18.5 kg /m2: 120.3±33.3 cm2, p=0.004) (figure 1). Postoperative clinical recurrence was observed in 17.8% (8/45) of patients at 6 months. Patients with clinical recurrence had a significantly lower SMA (87.4 ± 18.5 cm2) compared to those without clinical recurrence (120.9 ± 39.2 cm2) (p=0.001) (figure 2). Patients with a lower SMA were 1.1 times more likely to have clinical recurrence at 6 months compared to patients with a higher SMA (OR 1.05 (CI 1.01-1.10)(p=0.022)). Conclusion Sarcopenia is highly prevalent in preoperative CD patients. Patients with early clinical recurrence had a significantly lower SMA. SMA may be useful in predicting CD patients at risk of early postoperative clinical recurrence. However, more research is needed to confirm study findings.

P420 Safety & feasibility of targeted mesenteric approaches to ileocolic resection and anastomosis in Crohn’s Disease

Abstract Background More than 80% of patients with Crohn's disease (CD) require surgical intervention during their lifetime. High rates of disease recurrence often necessitate repeat surgery. Recurrence is typically observed at or immediately proximal to the anastomosis, raising the question of whether surgical techniques have the potential to decrease recurrence rates. In addition, the mesentery has recently been implicated in the pathophysiology of CD, and several techniques have been developed to reduce its influence on recurrence. We aimed to describe the short-term safety and feasibility of these approaches. Methods This is a comparative retrospective single-center cohort study of consecutive CD patients undergoing primary or redo ileocolic resection with mesenteric excision and exclusion (MEE), extended mesenteric excision (EME) only, or Kono-S anastomosis (KSA) only from 2015-2022. Patients undergoing both EME plus KSA were considered to have MEE. Patients' characteristics, perioperative data, and short-to-midterm outcomes were collected. Univariate analysis was performed. Results A total of 186 patients underwent MEE (n=46), EME (n=66), or KSA (n=74). All three groups had comparable (p>0.05) risk factors in terms of mean age at diagnosis and surgery (25.4 and 37.5 years old, respectively), preoperative biologics (63.4%) and corticosteroids (22.6%), smoking, and associated perianal disease. However, the MEE group had more penetrating disease compared to the other groups (MEE 50.0% vs. EME 34.8% vs. KSA 20.4%; p<0.01). Overall there were no differences (p>0.05) in rates of emergency surgery (4.8%), ileostomy creation (14%), and laparoscopy (64.5%) Table 1. Estimated blood loss and length of stay were also comparable between groups (p>0.05). Operative time in the MEE group was longer (median: 187, range: 67-360 minutes) compared to the other two groups (KSA: 170 (56-487); EME: 152 (63-436, p<0.01). Post-operatively, the groups had similar lengths of stay (4 days), rates of readmissions (9.1%) and major postoperative complications (6.5%). After a median overall follow-up of 8 months (0-86), endoscopic (18.8%) and surgical recurrences (1.1%) did not differ between groups (p>0.05) Table 2. Conclusion Targeting the mesentery with novel surgical approaches to ileocolic Crohn's disease was observed to be safe and feasible on short-term follow-up. Long-term follow-up is needed to assess the impact of these techniques on post-operative anastomotic disease recurrence.

P242 Universal exclusion of patients with Permanent Ileostomy in Crohn’s disease clinical trials: A systematic review

Abstract Background Crohn’s disease (CD) can be progressive leading to complications such as strictures and fistula requiring surgery in up to 50% of patients within 10 years of diagnosis and increased risk of permanent ileostomy (PI) formation. Approximately one third of patients with PI experience clinical recurrence within the small bowel which may need medical therapy and 16% significant recurrence requiring further surgery. Despite the physical and psychological morbidity associated with PI formation, there is a paucity of research in patients with CD and PI. We performed a systematic review to investigate whether patients with CD and PI were eligible to take part in pharmaceutical clinical trials. Methods MEDLINE, Embase, and the Cochrane library (CENTRAL) databases were searched from inception to April 2022 for randomized, placebo-controlled induction and maintenance trials of biologics and small molecules in adult patients with active CD. Eligibility criteria of included studies were screened by two authors independently. The primary outcome was to determine the proportion of trials that included patients with CD and a PI. Trial characteristics such as number of participants, mean age, sex, trial phase, class of drug, inclusion, or exclusion of patients with ostomy were collected. Results After excluding duplicates 11693 records from databases and additional sources were selected for screening. In total,144 records were assessed for full text assessment and 81 studies (induction: 58 and maintenance: 23) which enrolled 22000 participants were considered eligible (Table 1). The majority were phase 2 trials (n=41, 50.6%), 86.4% (n=70) evaluated efficacy and safety of biologics and the remaining studies (n=11, 13.6%) evaluated oral small molecules. Amongst the induction trials, 39 (67.2%) specifically stated that they excluded patients with an ostomy and the remaining studies (n=19, 32.8%) did not comment. For maintenance trials, 16 (69.6%) stated that they excluded patients with an ostomy and the remaining seven (30.4%) studies did not comment. Twenty-one induction studies and thirteen maintenance studies reported the proportion of patients with prior intestinal resection which ranged from 2.4% to 51%. No clinical trial included patients with a PI. Conclusion Patients with CD and PI have been excluded from pharmaceutical trials of biologics and small molecules to date. This group represents a high-risk patient population that have developed penetrating disease and may require medical therapy to prevent and treat recurrence. There is an urgent need to identify barriers to enrolment and develop eligibility and outcome measures that enable inclusion of patients with CD and PI into clinical trials.

P240 Low surgery rates first year after diagnosis in Crohn’s disease; results from a large population-based inception cohort - the IBSEN III study

Abstract Background Surgery rates in Crohn’s disease (CD) have declined during recent years, in parallel with the introduction and increased use of biological treatment. The aim of this study was to describe the use of first-line biologic therapy and to estimate the intra-abdominal surgery rate during the first year after the CD diagnosis. Methods The Inflammatory Bowel Disease in South-Eastern Norway III (IBSEN III) study is a population-based inception cohort with a prospective follow-up of newly diagnosed inflammatory bowel disease patients from the South-Eastern Health Region of Norway included in the period 2017 to 2019. Five hundred and seven patients ≥18 years were diagnosed with CD and those attending the one-year follow-up visit were included in this study. Clinical data, including Montreal classification, were registered at time of diagnosis. At the one-year follow-up, use of biologic therapy and need for CD-related intra-abdominal surgery since diagnosis were registered. Kaplan-Meier plots estimated the cumulative incidence of first-line biologic therapy and intra-abdominal surgery. Results A total of 431/507 (85%) CD patients attended the one-year follow-up and were included, 54.8% female, median age 37 years (range 18-80). At diagnosis 218 (50.6%) presented with ileal disease location, 76 (17.6%) colonic and 137 (31.8%) ileocolonic disease location, while 11 (2.6%) also had upper gastrointestinal involvement. The majority, 351 (81.4%), had a non-stricturing non-penetrating disease behavior, 70 (16.2%) a stricturing and 10 (2.3%) a penetrating disease behavior, while 17 (3.9%) also had perianal disease. Within one year of follow-up, 165 (38.7%) received at least one biologic therapy (60.6% infliximab, 35.8% adalimumab and 3.6% vedolizumab). Seven patients (1.6%) underwent perianal surgery and 21 (4.9%) had intra-abdominal surgery within the first year. Three of these were diagnosed during their primary surgery. Time from diagnosis to start of first-line biologic therapy and first intra-abdominal surgery is shown in Figure 1 and Figure 2, respectively. Figure 1: Kaplan-Meier plot showing cumulative incidence of first-line biologic therapy. Figure 2: Kaplan-Meier plot showing cumulative incidence of Crohn's related intra-abdominal surgery. Conclusion In the IBSEN III cohort, the rate of intra-abdominal surgery during the first year of disease was low (4.9%) compared to a previous population-based study from the same geographic area during the pre-biologic era, the IBSEN study, where the surgery rate was reported as 15.9 %.1 We hypothesize that a large preponderance of patients presenting with milder phenotypes at diagnosis combined with high use of biologicals contribute to the low surgery rates.

P561 Risk of stoma formation in patients with Crohn’s perianal fistulas over a two decades period. A cohort study from a tertiary referral center.

Abstract Background Optimal management of perianal Crohn’s disease (pCD) consists of combined medical (preferentially anti-TNF) and surgical treatment. However, it is still unclear if this has improved outcomes. This study aimed to described outcome and prognosis of pCD patients at a referral center over almost two decades. Methods All pCD patients referred for active perianal fistulas between 2000-2018 at our center were considered eligible for this retrospective study. Patients were divided into two groups according to the date of pCD diagnosis: period A (2000-2006) and period B (2006-2018). The complement of Kaplan-Meier estimates were used to visualize the time since pCD diagnosis until temporary and definitive fecal diversion. Clinically important outcomes such as need for temporary or permanent fecal diversion, and factors associated to these outcomes were evaluated by Cox regressions models. Results A total of 336 patients with active pCD were identified. The mean interval between the diagnosis of CD and the perineal fistulizing disease was 4.9 years (+-7.64). Mean follow up was 10.83 years (SD ± 4.5). The two groups were similar for demographic and clinical characteristics, except for the cumulative exposure to biologicals prior to pCD diagnosis [27.8% vs 46.9% in period A and B, respectively (p<0.001)]. (Table 1) The risk for temporary and definitive fecal diversion was higher for group B, at 5- [temporary stoma: 10.8 CI (6.7%-17.3%) vs 27.3% CI (21.1%-34.9%), p<0.001; definitive stoma: 0.7% CI (0.1%-4.8%) vs 13.1% CI (8.7%-19.5%), p=0.002] and 10-years follow-up [temporary stoma: 23.3% CI (17%-31.5%) vs 39.0% CI (31.1%-48.1%), p<0.001; definitive stoma: 11.7% CI (7.2%-18.7%) vs 19.9% CI (13.9-28.0%), p=0.002], respectively. (Figure 1 and Figure 2). At multivariate analysis, the presence of extraintestinal manifestations [HR 2.55 CI (1.40-4.62)], B2 stricturing disease [HR 4.43 CI (1.46-13.4)], B3 penetrating disease [HR 7.10 CI (2.37-21.27)], and diagnosis of pCD diagnosis after 2006 (period B) [HR 2.20 CI (1.16-4.17)], were independent risk factors for need for permanent ileostomy. (Table 2) Conclusion This retrospective analysis spanning almost twenty years shows that prognosis of CD patients affected by anal fistulas remains poor and has not much changed over time, despite the introduction of biologicals and new surgical techniques. The observed increase in definitive fecal diversion in more recent years can be partially explained by referral bias and/or a more aggressive clinical management of the most severe cases. Extraintestinal manifestations and synchronous complicated luminal disease increased the risk of definitive stoma in the long-term.

COMPARATIVE EFFECTS OF BIOLOGICS IN PREVENTING PENETRATING COMPLICATIONS IN CROHN’S DISEASE

Abstract BACKGROUND Comparative efficacy of biologics is an important consideration when selecting therapies for Crohn’s disease (CD). While recent studies have focused on clinical remission, few studies have assessed the comparative efficacy of biologics in preventing penetrating disease (PD) complications of CD. The aim of our study was to compare the rates of penetrating complications (luminal and perianal) between biologics used as first-line therapies in CD. METHODS A propensity-score adjusted retrospective comparative effectiveness study was performed using IBM® MarketScan® Commercial Database (2006-2020). We included adults (≥18 years) with CD (≥3 administrative claims for CD [K50.*]) who initiated their first biologic (anti-tumor necrosis factor [anti-TNF], ustekinumab ([UST]) or vedolizumab [VDZ]). with ≥ 2 consecutive years of health insurance enrollment during study period (at least 1 year following index date). Patients with pre-existing luminal penetrating disease (LPD) or perianal penetrating disease (PPD) or prior biologic exposure were excluded using a minimum look-back period of 1 year. LPD was identified by ICD claims (537.4, 567.2X, 569.X, 593.82, 596.1, 619.1, K31.6, K65.X, K63.X, N82, N32.1) and PPD by a validated case definition. Patients were followed until a PD event and censored if a new biologic class was initiated, loss of medical coverage or study end. Cohorts were balanced by inverse probability of treatment weighting based on age, sex, Elixhauser comorbidity score, and prior CD surgery. Pairwise comparisons of biologic classes were performed by cox-proportional hazard models with medication exposure treated as a time-dependent variable based on a medication possession ratio of 0.8. RESULTS A total of 40693 patients with CD without prior penetrating disease (54.1% female, median age 39 years [IQR; 28-50]) initiated biologic therapy: 37839 (93.0%) anti-TNF, 1194 (3.0%) UST and 1660 (4.0%) VDZ. Penetrating complications developed in 8567 (21.1%) patients: 2,204 (5.4%) LPD and 7,474 (18.4%) PPD. Compared with no medication exposure, anti-TNFs were protective against composite (Figure 1, HR 0.91; 95% confidence interval (CI), 0.84 - 0.98, p = 0.013) and LPD (HR 0.59; CI, 0.50 - 0.69; p <.0001) but not PPD (HR, 0.99; CI, 0.91 - 1.07; p = 0.78). Neither VDZ nor UST were protective against composite, LPD or PPD. In pairwise comparisons, anti-TNF was significantly protective against composite (Figure 2, HR 0.92; CI, 0.85 – 0.99; P = 0.018) and LPD (HR 0.51; CI, 0.44 – 0.60; p <.0001) compared with VDZ and for LPD compared with UST (HR, 0.71; CI, 0.61 – 0.83, p <.0001). CONCLUSIONS Anti-TNF therapy was protective against developing LPD and may offer an advantage over VDZ and UST in preventing this disease complication. Further studies are needed to validate these findings and to determine potential reasons for these differences. Figure 1: Comparison of biologics in preventing the composite outcome of penetrating complications in patients with Crohn's disease. Figure 2: Comparison of anti-TNF versus vedolizumab in preventing composite outcome of penetrating complications in patients with Crohn's disease

SUBCUTANEOUS INFLIXIMAB IN REFRACTORY CROHN'S DISEASE PATIENTS AFTER THE MULTIPLE TREATMENT FAILURES - SHORT TREATMENT OUTCOMES

Abstract BACKGROUND Subcutaneous administration of infliximab shows an increased benefit in terms of pharmacokinetics and pharmacodynamics effects compared to the intravenous infliximab. The practical question arises whether routine administration in refractory CD patients who have failed prior biological therapy will provide "biobetter" clinical efficacy. AIMS We propose a single center study designed to evaluate SC-IFX treatment outcomes in patients with active CD after the previous failures of other biologicals (TMAbs). Such a refractory CD cohort was chosen because there is currently insufficient appropriate medication therapy available for these patients and the identification of parameters predicting response to SC-IFX treatment could be of great benefit to some of them. PATIENTS & METHODS A total of 32 CD patients were included, with the median age of 34.5 years and median CD duration of 11 years; >90% of them with stricturing and/or penetrating disease behavior, >80% with ileocolic involvement, and about 40% with the active perianal disease. Eighteen of 32 patients (56%) have failed on ≥3 previous TMAbs, the rest on 2 previous TMAbs. Twenty (62.5%) of n = 32 have had IV-IFX in past; in this sub-cohort, 85% of patients have positive anti-IFX antibodies (ATI). In ATI-positive sub-cohort, induction of SC-IFX was realized with four 120 mg SC doses weekly. Two induction IV infusions of 5 mg/kg IFX were administered in 2-week intervals in ATI-negative sub-cohort. Maintenance treatment in whole cohort consisted of 120 mg SC IFX bi-weekly. RESULTS Of the 32 patients, 7 individuals have failed the treatment during the induction phase: one because of heart disease progression, and 6 patients due to delayed hypersensitivity reactions with systemic manifestation. In 25/32 patients who continued their treatment up to W14, the initial median Harvey-Bradshaw index (HBI) of 6 (min 1, max 28) did not decrease significantly within the 14 weeks of treatment (p=0.067). However, both the serum CRP level (p=0.039) and fecal calprotectin level (p=0.027) have shown significant decrease. Median trough IFX levels have increased from 6 μg/mL at W2 to 10 μg/mL at W14 (p<0.001), and median ATI levels dropped from median of 38 ng/mL to 5 ng/mL (p= 0.0004). None of the patients with initial zero ATI levels have shown new ATI formation. Moreover, in 10 of 17 patients (59%) with the initial ATI positivity, ATI serum levels have decreased significantly even to the cut-off levels. The only risk factor for SC-IFX discontinuation before W14 was a high serum levels of ATIs (p < 0.001). CONCLUSIONS Our short-term experience with SC-IFX shows the treatment efficacy and tolerability in complicated CD patients after multiple TMAbs failures.The research gap in information about biobetters in patients with IBD must be filled and predictive factors for the response to SC-IFX must be found.

Targeting lipid metabolism as a new therapeutic strategy for inherited cardiomyopathies.

Inherited cardiomyopathies caused by pathological genetic variants include multiple subtypes of heart disease. Advances in next-generation sequencing (NGS) techniques have allowed for the identification of numerous genetic variants as pathological variants. However, the disease penetrance varies among mutated genes. Some can be associated with more than one disease subtype, leading to a complex genotype-phenotype relationship in inherited cardiomyopathies. Previous studies have demonstrated disrupted metabolism in inherited cardiomyopathies and the importance of metabolic adaptations in disease onset and progression. In addition, genotype- and phenotype-specific metabolic alterations, especially in lipid metabolism, have been revealed. In this mini-review, we describe the metabolic changes that are associated with dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM), which account for the largest proportion of inherited cardiomyopathies. We also summarize the affected expression of genes involved in fatty acid oxidation (FAO) in DCM and HCM, highlighting the potential of PPARA-targeting drugs as FAO modulators in treating patients with inherited cardiomyopathies.

Oncological outcomes of Crohn's disease-associated cancers focusing on disease behavior.

The overall risk of colorectal cancer in Crohn's disease (CD) is higher than in the general population, and CD-associated cancer (CDAC) has poorer prognosis than sporadic cancer. Developing treatment strategies for improving the prognosis of CDAC, we evaluated the characteristics of CDAC according to the underlying disease behavior, namely stricturing and penetrating. This multicenter retrospective study comprises 316 CDAC patients who underwent surgery between 1985 and 2019. Clinicopathological findings including disease behavior and oncological outcomes were investigated. There was no association between the preoperative course of CDAC patients and disease behavior; however, postoperative information revealed distinctly different characteristics between CDAC patients with stricturing behavior and those with penetrating behavior (stricturing with lymphatic invasion and peritoneal dissemination recurrence, and penetrating with histologically poorly differentiated and local recurrence). Oncological outcome of patients with CDAC was distinctly different according to disease behavior, as penetrating provided a poor outcome (overall survival [OS]: p=0.02; relapse-free survival [RFS]: p=0.002) whereas stricturing had no effect. Furthermore, penetrating behavior was identified as one of the independent risk factors for poor OS and RFS (OS: hazard ratio [HR] 1.89, 95% confidence interval [CI] 1.16-3.09, p=0.01; RFS: HR 2.15, 95% CI 1.28-3.63, p=0.004). Our study highlights the different characteristics of CDAC according to the underlying disease behavior and substantiates the poor prognosis of CDAC patients with penetrating behavior. Treatment planning including screening, surgical procedures, and postoperative treatment, with awareness of these findings, may contribute to improved prognosis for CDAC patients.

Evaluating gap junction variants for a role in pediatric cataract: an overview of the genetic landscape and clinical classification of variants in the GJA3 and GJA8 genes

ABSTRACT Introduction Variants in the two lens-expressed gap junction genes GJA3 and GJA8 are among the most common causes of inherited pediatric cataract. These two genes alone account for up to 18% of the cases, second only to the crystallin gene family. Areas covered All published cataract-associated variants in the GJA3 and GJA8 genes were reviewed for a role in pediatric cataract. Autosomal dominant inheritance was most frequently reported, alongside instances of reduced penetrance and autosomal recessive disease. Variant curation using the ACMG-AMP guidelines identified that many variants do not meet the modern standards for clinical interpretation of pathogenicity. There is broad phenotypic heterogeneity of cataract associated with gap junction gene variants. Pathogenic variants are located throughout both proteins with an enrichment in the N-terminal, first two transmembrane domains, and two extracellular loops. Expert opinion Nearly half the gap junction gene variants observed in cataract patients lack sufficient evidence of pathogenicity to form a useful clinical opinion. For many variants, this may be rectified over time as the variant is observed in additional patients but would be vastly accelerated by the generation of well-characterized and standardized functional data evaluating the specific effect of each variant on protein function.

Two-year real-world outcome data from a single tertiary centre shows reduced ustekinumab persistence in a non-bio-naïve Crohn's disease cohort with penetrating disease, -ostomies and sarcopenia.

Ustekinumab was approved in 2016 for the treatment of moderate-severe Crohn's disease (CD). Clinical trials and real-world studies have suggested ustekinumab to be a safe and effective treatment; however, studies to date infrequently use imaging techniques to predict response to biologics in CD. We assessed the 2-year real-world effectiveness and safety of ustekinumab in a tertiary CD cohort with the use of novel imaging techniques. Retrospective cohort study. Retrospective data were collected between 2016 and 2021. Study end points included ustekinumab persistence, biological and/or clinical response and remission at 12, 18 and 24 months. Statistical analysis included demographic and inferential analyses. In all, 131 CD patients [57.3% female, median age of 26.0 (21.0-37.0)] were included. Patients were non-bio naïve, and the majority received ustekinumab as third- or fourth-line treatment. At 24 months, 61.0% (80/131) persisted with ustekinumab [52.7% (69/131) steroid free]. Clinical response was reported in 55.2% (37/67), clinical remission in 85.7% (57/67), biological response in 46.8% (22/47) and biological remission in 31.9% (15/47) of patients at 24 months. The low outcome numbers were attributable to missing data. Improvements in routine disease markers, including C-reactive protein and Harvey-Bradshaw Index, were also reflected in magnetic resonance imaging-derived disease scores. The presence of penetrating CD, an -ostomy and sarcopenia were all predictors of poorer ustekinumab outcomes (p < 0.05). Ustekinumab is effective in non-bio-naïve CD patients with non-stricturing, non-penetrating disease with an unremarkable safety profile but may be less effective in those with penetrating disease, -ostomies and sarcopenia.

Inflammatory bowel disease in the elderly: A focus on disease characteristics and treatment patterns.

As the population ages, the number of elderly inflammatory bowel disease (IBD) patients is expected to increase. The clinical features and therapeutic options for young and old patients may differ, as elderly IBD patients are likely to have different comorbidities and disease characteristics. The goal of this study was to examine the clinical aspects and therapeutic choices for elderly Saudi IBD patients. We conducted a retrospective study aimed at describing the demographic, clinical, and management characteristics of IBD in elderly patients (≥60 years) who followed up at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia. The data was extracted from the KAUH inflammatory bowel disease information system (IBDIS) registry. The primary outcome was to describe disease characteristics in accordance with the Montréal classification and the secondary outcomes were to describe treatment patterns and identify significant clinical associations. Our data were collected from 76 patients who fulfilled the study inclusion criteria. Females outnumbered males (53.9% vs 46.1%) and the mean age was 51.5 ± 9.7 years. Essential hypertension (26.3%) was the most common comorbidity followed by diabetes mellitus (23.6%), and malignant neoplasms (9.21%). More than half of the patients with Crohn's disease (CD) had disease onset after forty years of age. The most common form of disease distribution was ileocolonic disease (64.7%). Less than 17% of patients had a penetrating disease phenotype. About 88 percent of patients with UC presented >40 years of age. Approximately, half of the cohort had left-sided ulcerative colitis (UC) (48%), followed by pancolitis (40%). The most prescribed medication class for IBD was 5-aminosalicylic acid (5-ASA) derivatives (56.58%) followed by corticosteroids and immunosuppressive drugs. In Saudi Arabia, age-specific concerns including comorbidities and polypharmacy remain the major challenges in the management of elderly IBD patients.

Ustekinumab and vedolizumab for the prevention of postoperative recurrence of Crohn's disease: Results from the ENEIDA registry.

Anti-TNF agents are the only effective biological agents for the prevention of postoperative recurrence (POR) in Crohn's disease (CD). However, they are contraindicated or have been shown to fail in some patients. Although ustekinumab and vedolizumab were licensed for CD some years ago, data in this setting are scarce. All CD patients in whom ustekinumab or vedolizumab was prescribed for the prevention of POR within three months of ileocolonic resection with anastomosis were identified from the ENEIDA registry. The development of endoscopic, clinical and surgical POR was registered. Forty patients were treated for the prevention of POR with ustekinumab and 25 were treated with vedolizumab. Eighty per cent had at least one risk factor for POR (prior resections, active smoking, perianal disease or penetrating disease behaviour). All the patients had been exposed to anti-TNF therapy. After a median follow-up of 17 and 26 months, the cumulative probability of clinical POR at 12 months after surgery was 32% and 30% for ustekinumab and vedolizumab, respectively. Endoscopic assessment within the first 18 months after surgery was available for 80% of the patients on ustekinumab and 70% for those on vedolizumab. The rate of endoscopic POR was 42% for ustekinumab and 40% for vedolizumab. One patient treated with ustekinumab and two with vedolizumab underwent a new intestinal resection. Ustekinumab and vedolizumab seem to be effective in the prevention of POR in patients at high risk. Our results warrant controlled trials comparing these drugs with conventional therapies.

How T118M peripheral myelin protein 22 predisposes humans to Charcot–Marie–Tooth disease

Data from gnomAD indicates that a missense mutation encoding the T118M variation in human peripheral myelin protein 22 (PMP22) is found in roughly 1 of every 75 genomes of western European lineage (1:120 in the overall human population). It is unusual among PMP22 variants that cause Charcot-Marie-Tooth disease (CMT) in that it is not 100%-penetrant. Here, we conducted cellular and biophysical studies to determine why T118M PMP22 predisposes humans to CMT, but with only incomplete penetrance. We found that T118M PMP22 is prone to mistraffic, but differs even from the WT protein in that increased expression levels do not result in a reduction in trafficking efficiency. Moreover, the T118M mutant exhibits a reduced tendency to form large intracellular aggregates relative to other disease mutants and even WT PMP22. NMR spectroscopy revealed that the structure and dynamics of T118M PMP22 resembled those of WT. These results show that the main consequence of T118M PMP22 in WT/T118M heterozygous individuals is a reduction in surface-trafficked PMP22, unaccompanied by formation of toxic intracellular aggregates. This explains the incomplete disease penetrance and the mild peripheral neuropathy observed for WT/T118M CMT cases. We also analyzed BioVU, a large biobank linked to de-identified electronic medical records, and found a statistically robust association of the T118M mutation with the occurrence of long and/or repeated episodes of carpal tunnel syndrome. Collectively, our results both illuminate the cellular effects of the T118M PMP22 variation leading to CMT disease and indicate a second disorder for which it is a risk factor.

Low disease risk and penetrance in Leber hereditary optic neuropathy

The risk of Leber hereditary optic neuropathy (LHON) has largely been extrapolated from disease cohorts, which underestimate the population prevalence of pathogenic primary LHON variants as a result of incomplete disease penetrance. Understanding the true population prevalence of primary LHON variants, alongside the rate of clinical disease, provides a better understanding of disease risk and variant penetrance. We identified pathogenic primary LHON variants in whole-genome sequencing data of a well-characterized population-based control cohort and found that the prevalence is far greater than previously estimated, as it occurs in approximately 1 in 800 individuals. Accordingly, we were able to more accurately estimate population risk and disease penetrance in LHON variant carriers, validating our findings by using other large control datasets. These findings will inform accurate counseling in relation to the risk of vision loss in LHON variant carriers and disease manifestation in their family. This Matters Arising paper is in response to Lopez Sanchez etal. (2021), published in The American Journal of Human Genetics. See also the response by Mackey etal. (2022), published in this issue.

Is the disease risk and penetrance in Leber hereditary optic neuropathy actually low?

Pedigree analysis showed that a large proportion of Leber hereditary optic neuropathy (LHON) family members who carry a mitochondrial risk variant never lose vision. Mitochondrial haplotype appears to be a major factor influencing the risk of vision loss from LHON. Mitochondrial variants, including m.14484T>C and m.11778G>A, have been added to gene arrays, and thus many patients and research participants are tested for LHON mutations. Analysis of the UK Biobank and Australian cohort studies found more than 1 in 1,000 people in the general population carry either the m.14484T>C or the m.11778G>A LHON variant. None of the subset of carriers examined had visual acuity at 20/200 or worse, suggesting a very low penetrance of LHON. Haplogroup analysis of m.14484T>C carriers showed a high rate of haplogroup U subclades, previously shown to have low penetrance in pedigrees. Penetrance calculations of the general population are lower than pedigree calculations, most likely because of modifier genetic factors. This Matters Arising Response paper addresses the Watson etal. (2022) Matters Arising paper, published concurrently in The American Journal of Human Genetics.

The Genetic Spectrum of Maturity-Onset Diabetes of the Young (MODY) in Qatar, a Population-Based Study.

Maturity-onset diabetes of the young (MODY) is a rare monogenic form of diabetes mellitus. In this study, we estimated the prevalence and genetic spectrum of MODY in the Middle Eastern population of Qatar using whole-genome sequencing (WGS) of 14,364 subjects from the population-based Qatar biobank (QBB) cohort. We focused our investigations on 14 previously identified genes ascribed to the cause of MODY and two potentially novel MODY-causing genes, RFX6 and NKX6-1. Genetic variations within the 16 MODY-related genes were assessed for their pathogenicity to identify disease-causing mutations. Analysis of QBB phenotype data revealed 72 subjects (0.5%) with type 1 diabetes, 2915 subjects (20.3%) with type 2 diabetes and 11,377 (79.2%) without diabetes. We identified 22 mutations in 67 subjects that were previously reported in the Human Genetic Mutation Database (HGMD) as disease-causing (DM) or likely disease causing (DM?) for MODY. We also identified 28 potentially novel MODY-causing mutations, predicted to be among the top 1% most deleterious mutations in the human genome, which showed complete (100%) disease penetrance in 34 subjects. Overall, we estimated that MODY accounts for around 2.2-3.4% of diabetes patients in Qatar. This is the first population-based study to determine the genetic spectrum and estimate the prevalence of MODY in the Middle East. Further research to characterize the newly identified mutations is warranted.

Large family genetic analysis: effects of variegated porphyria and hemophilia b on reproductive traits

Introduction. The relevance of the study of genetic pathologies is due to the growing prevalence in most countries, disability and mortality of persons, high costs of support and treatment. The modern classifications include various forms of porphyria and hemophilia. The study of pathologies in historical persons, when it is possible to collect information from different sources regarding members of a large family over a long period of time, is of interest for understanding the mechanisms of the development of the disease at the present time. Aim is to analyze the genetic characteristics of variegated porphyria and hemophilia B in a large family. Materials and methods. Data from current guidelines and clinical protocols, scientific literature and genetic databases (OMIM) on various forms of porphyria and hemophilia are analyzed. Information about 1362 people from the British royal family in 18–20th centuries was collected from open sources and scientific literature. A pedigree of 10 generations, 27 nuclear families with persons with variegated porphyria and hemophilia B has been compiled. Genealogical, segregation, linkage, statistical analysis was performed. The results were used to study reproductive traits. Results. Genealogical analysis showed a family accumulation of porphyria – its prevalence among relatives in a large family was 1,8 %, which is three orders of magnitude higher than among the population of different countries. It was established that there is no statistically significant difference in the sex ratio among patients with the specified pathologies. Data from genealogical and segregation analysis and a penetration rate of 92 % suggest an autosomal dominant type inheritance with incomplete penetrance of disease which is consistent with the literature. The independent nature of inheritance of variegated porphyria and hemophilia B was established. It was found that in persons with porphyria reproductive traits are 3,3–4,1 times differ than the reproductive traits of persons with porphyria and hemophilia at the same time. A statistically significant difference was established between the analyzed traits of patients with porphyria, who at the same time are carriers of the mutation that causes hemophilia, and the indicators of healthy individuals.

Pre-Clinical Investigation of a Novel Small Molecule Inhibitor Targeting YBX1 in AML

Recently, our group identified the pleiotropic DNA and RNA binding protein YBX1 as a specific dependency and therapeutic target in acute myeloid leukemia (AML) that is essential for stabilizing oncogenic transcripts and thereby maintains oncogenic protein expression (Perner et al., 2021). Selective pharmacologic targeting of YBX1 in AML, however, has not been achieved so far. Here, we investigate the functional consequences of a novel small molecule inhibitor (SU056) of YBX1 in AML. We examined the viability of several human AML cell lines (MOLM13, HL60, EOL1, THP1, Kasumi1, ML2, Mv4;11, OCI-AML3, NOMO1) upon SU056 treatment and found significant reduction of cell growth in a concentration dependent manner. Inhibition of cell growth could be mainly attributed to impaired proliferative capacity at nanomolar concentrations. Pharmacologic inhibition of YBX1 resulted in impaired colony formation (mean colony number DMSO: 231.3±13.88 vs. SU056 500nM: 154.7±8.29; p<0.0001), cell cycle arrest (cells in S phase: DMSO: 37.3±2.4 vs. SU056 500nM: 27.2±1.67; p=0.0127) and induction of myeloid differentiation. Consistently, in a xenograft model of human AML, SU056 treatment resulted in prolonged disease latency (MOLM13 diluent: 62 days OS vs. SU056: not reached, p=0.0013; OCI-AML3 diluent: 79 days OS vs. not reached, p=0.0001) and significant reduction of disease penetrance (MOLM13 diluent: 100% vs. SU056: 24,9%; OCI-AML3 diluent: 100% vs. SU056: 9,1%). Consistently, percentage of SU056 treated human leukemic cells in the bone marrow of recipient mice was decreased for both, MOLM13 (mean diluent: 41,3% vs. SU056: 7,6%) and OCI-AML3 (mean diluent: 28,9% vs. SU056: 2,9%). Likewise, pharmacologic inhibition of YBX1 reduced colony formation and total cell numbers of primary human AML cells in a dose-dependent manner. To be clinically relevant, such treatment must have a suitable therapeutic index between human hematopoietic stem- and progenitor cells (HSPCs) and their malignant counterpart. This is particularly important, considering the role of YBX1 in mRNA splicing and processing. Of note, pharmacologic inhibition of YBX1 did not perturb colony formation of normal HSPCs derived from apheresis donors. These findings were confirmed by investigating primary human leukemic cells in a patient-derived xenograft (PDX) model of AML. We aimed to assess whether loss in leukemia cell competition induced by pharmacologic targeting of YBX1 is sufficient for normal hematopoietic cells to outcompete leukemic cells in vivo. 1x106 normal human HSPCs were transplanted along with 2x104 leukemic cells to assess for efficacy of SU056-treatment versus diluent control. In vivo treatment with SU056 (20mg/kg, i.p.) for 3 weeks resulted in a significant decrease in the AML blast number in the PB (mean blast %: diluent: 38.5%; SU056: 2.25%; p<0.0001). This resulted in increased survival of SU056 treated recipients (OS diluent: 83 days vs. SU056: not reached). To confirm the proposed mechanism by which SU056 impairs leukemia growth we performed global transcriptome and proteome analysis following treatment with SU056 (500nM, 96h). Proteome profiling revealed a total of 2641 deregulated proteins. Gene-ontology analysis indicated deregulation of YBX1 targets and proteins associated with cell cycle, DNA repair, mRNA splicing/processing, and transcriptional regulation. Of note, overlap between transcriptional regulation (as determined by mRNA-Seq) and changes in proteome abundance revealed less than 5% target genes/proteins, indicating that SU056 may in fact interfere with binding of oncogenic mRNAs to YBX1 and thereby may reduce translation of oncogenic transcripts. In order to define functional consequences of pharmacologic YBX1 inhibition and explore potential vulnerabilities of drug combinations, we performed a genome-wide CRISPR/Cas9 screen in human AML cells treated with SU056 versus diluent control. Validation experiments are currently ongoing. Taken together, our data confirm the therapeutic potential to target YBX1 using the novel small molecule SU056. Given its broad applicability across genetic subtypes of AML and lack of toxicity on normal HSPCs, SU056 as a single agent or in combination with established targeted therapies may efficiently help to target and outcompete leukemic cells. Experiments to assess for potential synergy with already established targeted therapies will be presented.

Functional Role of Histone Variant macroH2A1 (H2AFY) in Acute Myeloid Leukemia (AML)

Histone variants can replace replication-coupled histones in the nucleosome. Among core histones, the H2A family exhibits highest sequence divergence resulting in the largest number of variants. Dysregulated expression of macrohistone (macroH2A) variants has been reported in different cancers. Their role in normal hematopoiesis and hematopoietic cancers remained so far poorly understood. We found high expression of macrohistone H2AFY (macroH2A1) in hematopoietic stem and progenitor cells (HSPCs) and primary AML as compared to differentiated hematopoietic cells. To assess for the functional dependency of human AML cells on macroH2A1, we performed in vitro CRISPR-Cas9 negative selection competition assays. Genetic inactivation of H2AFY in 4/9 AML cell lines (Molm-13, MV4;11, THP-1, OCI-AML3) resulted in outcompetition of H2AFY-deleted cells against non-deleted competitors. To confirm these findings in vivo, we performed xenotransplantation experiments. Genetic inactivation of H2AFY in human AML cells resulted in delayed leukemia development in recipient mice (median survival for NT-control: 35.5 days vs. H2AFY-KO: 44.0 days; p=0.002). To validate the functional impact of macroH2A1 on leukemic stem cells (LSCs), we generated a novel conditional knockout mouse model for H2AFY [B6(Cg)-H2afytm1Flh/J (H2afy flox/flox)]. Here, isolated lineage-depleted H2afy+/+, Mx1-Cre+ and H2afyfl/fl, Mx1-Cre+ bone marrow cells (Lin-BMCs) were retrovirally infected with MLL-AF9-GFP (MA9) and transplanted into sub-lethally irradiated recipient mice. Following establishment of leukemia, we transplanted 1x105 leukemic cells and inactivated H2afy in the leukemic cells by pIpC injection on day 7, 9 and 11 post-transplantation. Genetic deletion of H2afy resulted in delayed disease progression (median survival +/+: 83.5 days vs. -/-: 162.0 days, p=0.0013) and reduction of disease penetrance to 61%. Organ infiltration by leukemic cells led to disease development in a limited number of H2afy-/- recipient mice. Isolated H2afy-/- leukemic cells showed a decreased in proliferation and an increased in differentiation. Importantly, 37% of H2afy-/- recipient mice that developed AML showed only partial excision of H2afy, indicating selection of partially excised clones. Long-term survivors without leukemia development showed no molecular evidence for counterselection. Irrespective of the time of disease development and survival, immunophenotypic analysis of (Lin-cKit+Sca-1-FcγR+CD34+GFP+) LGMPs revealed decreased numbers of LSCs following H2afy-deletion (+/+: 2631/106 BMC; -/-: 727/106 BMC; p=0.0002). To assess for the functional consequences of H2afy-deletion on the LSC pool, we performed limiting dilution assays. When transplanting 1x105, 1x104, 1x103 and 1x102 H2afy+/+ or -/- leukemic cells into sub-lethally irradiated recipients, LGMP frequency in H2afy-deficient cells was significantly reduced (1/1 vs. 1/29928; p=1.25e-19). The reduction of LGMP frequency correlated with reduced plating efficiency and increased differentiation. Consistently, primary human AML cells showed impaired colony forming capacity following H2afy deletion (mean colony number NT-control: 60.0±17.1 vs. H2afy-KD: 30.1±8.9; p=0.0023). To assess for the impact of H2afy deletion on normal HSPCs, we performed competitive repopulation assays. Immunophenotypic abundance of HSPC in H2afy+/+ vs. -/- animals revealed comparable numbers in all relevant subpopulations. Serial competitive transplantation of H2afy+/+ and -/- BMC into primary and secondary recipient animals showed no competitive disadvantage or lack of self-renewal capacity of H2afy-/- cells. Likewise, colony formation of healthy human donor CD34+ cells was not impaired following depletion of H2AFY by RNAi. Transcriptome analysis of LGMP populations indicated increased of myeloid cell development and loss of LSC signatures in H2afy-deficient LGMPs. Likewise, ATAC-seq of H2afy+/+ and -/- LGMP population revealed profound changes in the chromatin structure and a strong correlation between chromatin accessibility and mRNA expression. Together, our results provide first evidence for a critical function of H2afy (macroH2A1) in models of AML while being dispensable for normal HSPC function. Experiments to assess for the mechanistic consequences of H2afy deletion on chromatin are currently under way.