Dominant Disease Research Articles

Malignant tumors in tuberous sclerosis complex: a case report and review of the literature

BackgroundTuberous sclerosis complex (TSC) is a rare, autosomal dominant genetic disease that arises from TSC1 or TSC2 genetic mutations. These genetic mutations can induce the development of benign tumors in any organ system with significant clinical implications in morbidity and mortality. In rare instances, patients with TSC can have malignant tumors, including renal cell carcinoma (RCC) and pancreatic neuroendocrine tumor (PNET). It is considered a hereditary renal cancer syndrome despite the low incidence of RCC in TSC patients. TSC is typically diagnosed in prenatal and pediatric patients and frequently associated with neurocognitive disorders and seizures, which are often experienced early in life. However, penetrance and expressivity of TSC mutations are highly variable. Herein, we present a case report, with associated literature, to highlight that there exist undiagnosed adult patients with less penetrant features, whose clinical presentation may contain non-classical signs and symptoms, who have pathogenic TSC mutations.Case presentationA 31-year-old female with past medical history of leiomyomas status post myomectomy presented to the emergency department for a hemorrhagic adnexal cyst. Imaging incidentally identified a renal mass suspicious for RCC. Out of concern for hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome, the mass was surgically removed and confirmed as RCC. Discussion with medical genetics ascertained a family history of kidney cancer and nephrectomy procedures and a patient history of ungual fibromas on the toes. Genetic testing for hereditary kidney cancer revealed a 5’UTR deletion in the TSC1 gene, leading to a diagnosis of TSC. Following the diagnosis, dermatology found benign skin findings consistent with TSC. About six months after the incidental finding of RCC, a PNET in the pancreatic body/tail was incidentally found on chest CT imaging, which was removed and determined to be a well-differentiated PNET. Later, a brain MRI revealed two small cortical tubers, one in each frontal lobe, that were asymptomatic; the patient’s history and family history did not contain seizures or learning delays. The patient presently shows no evidence of recurrence or metastatic disease, and no additional malignant tumors have been identified.ConclusionsTo our knowledge, this is the first report in the literature of a TSC patient without a history of neurocognitive disorders with RCC and PNET, both independently rare occurrences in TSC. The patient had a strong family history of renal disease, including RCC, and had several other clinical manifestations of TSC, including skin and brain findings. The incidental finding and surgical removal of RCC prompted the genetic evaluation and diagnosis of TSC, leading to a comparably late diagnosis for this patient. Reporting the broad spectrum of disease for TSC, including more malignant phenotypes such as the one seen in our patient, can help healthcare providers better identify patients who need genetic evaluation and additional medical care.

GATA binding protein 2 mediated ankyrin repeat domain containing 26 high expression in myeloid-derived cell lines

BACKGROUND Thrombocytopenia 2, an autosomal dominant inherited disease characterized by moderate thrombocytopenia, predisposition to myeloid malignancies and normal platelet size and function, can be caused by 5’-untranslated region (UTR) point mutations in ankyrin repeat domain containing 26 (ANKRD26). Runt related transcription factor 1 (RUNX1) and friend leukemia integration 1 (FLI1) have been identified as negative regulators of ANKRD26 . However, the positive regulators of ANKRD26 are still unknown. AIM To prove the positive regulatory effect of GATA binding protein 2 (GATA2) on ANKRD26 transcription. METHODS Human induced pluripotent stem cells derived from bone marrow (hiPSC-BM) and urothelium (hiPSC-U) were used to examine the ANKRD26 expression pattern in the early stage of differentiation. Then, transcriptome sequencing of these iPSCs and three public transcription factor (TF) databases (Cistrome DB, animal TFDB and ENCODE) were used to identify potential TF candidates for ANKRD26 . Furthermore, overexpression and dual-luciferase reporter experiments were used to verify the regulatory effect of the candidate TFs on ANKRD26 . Moreover, using the GENT2 platform, we analyzed the relationship between ANKRD26 expression and overall survival in cancer patients. RESULTS In hiPSC-BMs and hiPSC-Us, we found that the transcription levels of ANKRD26 varied in the absence of RUNX1 and FLI1. We sequenced hiPSC-BM and hiPSC-U and identified 68 candidate TFs for ANKRD26 . Together with three public TF databases, we found that GATA2 was the only candidate gene that could positively regulate ANKRD26 . Using dual-luciferase reporter experiments, we showed that GATA2 directly binds to the 5’-UTR of ANKRD26 and promotes its transcription. There are two identified binding sites of GATA2 that are located 2 kb upstream of the TSS of ANKRD26 . In addition, we discovered that high ANKRD26 expression is always related to a more favorable prognosis in breast and lung cancer patients. CONCLUSION We first discovered that the transcription factor GATA2 plays a positive role in ANKRD26 transcription and identified its precise binding sites at the promoter region, and we revealed the importance of ANKRD26 in many tissue-derived cancers.

C634Y mutation in RET-induced multiple endocrine neoplasia type 2A: A case report

BACKGROUND Multiple endocrine neoplasia type 2 (MEN2) is a rare, autosomal dominant endocrine disease. Currently, the RET proto-oncogene is the only gene implicated in MEN2A pathogenesis. Once an RET carrier is detected, family members should be screened to enable early detection of medullary thyroid carcinoma, pheochromocytoma, and hyperparatitity. Among these, medullary thyroid carcinoma is the main factor responsible for patient mortality. Accordingly, delineating strategies to inform clinical follow-up and treatment plans based on genes is paramount for clinical practitioners. CASE SUMMARY Herein, we present RET proto-oncogene mutations, clinical characteristics, and treatment strategies in a family with MEN2A. A family study was conducted on patients diagnosed with MEN2A. DNA was extracted from the peripheral blood of family members, and first-generation exon sequencing of the RET proto-oncogene was conducted. The C634Y mutation was identified in three family members spanning three generations. Two patients were sequentially diagnosed with pheochromocytomas and bilateral medullary thyroid carcinomas. A 9-year-old child harboring the gene mutation was diagnosed with medullary thyroid carcinoma. Surgical resection of the tumors was performed. All family members were advised to undergo complete genetic testing related to the C634Y mutation, and the corresponding treatments administered based on test results and associated clinical guidelines. CONCLUSION Advancements in MEN2A research are important for familial management, assessment of medullary thyroid cancer invasive risk, and deciding surgical timing.

#1790 Metformin versus standard of care in slowing progression of autosomal dominant polycystic kidney disease and correlation with total kidney volume

Abstract Background and Aims Autosomal dominant kidney disease (ADPKD) is the most common monogenic disorder leading to renal failure with very limited therapeutic options. Apart from lifestyle modifications and control of hypertension, tolvaptan is the only Food and Drug Administration (FDA) approved disease modifying drug. Although, it has proven therapeutic benefit in slowing disease progression in high risk Mayo Class (Mayo Class 1C-E), the aquaretic potential, potential hepatotoxicity and the cost limits its widespread use especially in resource constrained country. Metformin has been shown to be effective in ADPKD in preclinical studies and is also well tolerated by the general population. We planned this study to assess the efficacy and safety of metformin in non diabetic ADPKD patients. Method Our study is a prospective, randomized controlled, open labelled clinical trial of 52 non diabetic adults 18 to 60 years of age with typical ADPKD, estimated glomerular filtration rate (eGFR) > 45 ml/min/m2 and no risk factors of rapid progression. Participants were randomized in a 1:1 ratio by a computer-generated random number table into Metformin + standard of care group (Metformin arm) and standard of care group (Placebo arm). Primary outcome of the study was to evaluate the effects of metformin versus placebo arm on the percentage and absolute change in eGFR over 6-month period. Secondary outcomes were to study the effect of metformin versus placebo arm on the percentage and absolute change in height adjusted total kidney volume (htTKV ml/m) at 6 months, to evaluate the effect of baseline plasma copeptin levels with percentage change in htTKV and eGFR over 6 months, to evaluate metformin tolerability, to evaluate the effects of metformin versus placebo on the changes in body weight, BMI, blood pressure and urine protein excretion at 6 months period. Results Mean (SD) age of the cohort was 37.15 (10.16) years with half of them being females. The mean (SD) baseline htTKV and eGFR was 335.67 (153.3) ml/m and 100.23 (25.95) ml/min/m2. Clinical exome sequencing was available in 9 (17.3%) patients of which two third had PKD1 mutation. Baseline characteristics were distributed equally across randomized groups. Baseline proteinuria was significantly higher in the Metformin arm (p = 0.014). The eGFR difference and percentage change in eGFR was not different between the groups at 6 months (p = 0.535, 0.483). There was no statistically significant difference in htTKV difference and percentage change in htTKV at 6 months between the groups although increase in htTKV was numerically smaller in the metformin group (p = 0.769, 0.805). Blood pressure, weight, body mass index (BMI) and proteinuria also did not differ between two groups. Half of the cohort tolerated the maximum dose of metformin. Around 2/3rd patients reported adverse effects most commonly asthenia. There was no lactic acidosis or significant gastrointestinal side effects as assessed by gastrointestinal rating scale (GSRS) scale. Baseline copeptin levels did not correlate with eGFR or htTKV difference at 6 months. Conclusion Metformin appears to be safe and tolerable in non diabetic ADPKD patients over 6 months. However larger clinical trials are needed to conclude regarding the efficacy in terms of eGFR decline or htTKV progression.

#382 Unexpected diagnoses of ADTKD-MUC1 with the help of VNtyper

Abstract Background and Aims Autosomal dominant tubulointerstitial kidney disease (ADTKD) due to pathogenic variants in the MUC1 gene is difficult to diagnose since these variants lie in a large variable number tandem repeats (VNTR) and require specialized genetic testing, such as SNaPshot minisequencing. We recently developed a computational pipeline, VNtyper, for easier reliable detection of MUC1 VNTR pathogenic variants and have applied this tool to a large cohort of patients with various phenotypes of kidney disease. The aim of this study is to clinically describe patients in whom MUC1 pathogenic variants were unexpectedly detected with the help of VNtyper. Method We applied a computational pipeline, VNtyper, to a large cohort of patients with suspected hereditary kidney disease referred for genetic testing, regardless of their phenotype. This cohort included patients evaluated from 2017 to 2023 in the Molecular Genetics Department of Necker-Enfants Malades Hospital (Paris, France). Clinical characteristics were collected from patients in whom we detected new MUC1 VNTR pathogenic variants. Results 44 out of 3735 patients tested (1.2%) were newly diagnosed with a MUC1 pathogenic variant. Of these patients, ADTKD was clinically suspected in only 31 out of 44 patients (70%). In 2 patients, there was a pathogenic variant in another gene that could explain the phenotype, in addition to the MUC1 pathogenic variant. In fact, one 52-year-old patient had polycystic kidneys, nephrolithiasis, hematuria and normal kidney function. Her mother also had kidney cysts with absence of chronic kidney disease (CKD). This patient had a pathogenic variant in IFT140 gene (c.2399+1G>T) which could explain her autosomal dominant polycystic kidney disease (ADPKD) phenotype. Whether the MUC1 variant contributes to her disease remains unclear, especially seeing as her kidney function is normal at the age of 52 years. On the other hand, one patient had kidney cysts discovered at 3 days of age. A heterozygous HNF1B deletion was detected which could explain the phenotype. The following detection of a pathogenic MUC1 variant was thus an incidental finding and seemed de novo, although parents declined to get tested. These incidental findings can be challenging, especially when it comes to counselling and follow-up. There was no family history of kidney disease in 7 out of 44 patients (16%), and in one patient, we were able to confirm de novo disease since her parents were tested and were negative. It was unfortunately not possible to get DNA from the parents of the other patients. This is the first case of proven de novo ADTKD-MUC1 described to our knowledge. De novo variants in ADTKD-MUC1 are not surprising since the 7C stretch found in VNTR is a hotspot for mutagenesis. Interestingly, these patients seemed to have a more severe clinical presentation with an early onset of disease (median age at diagnosis 28 years [18, 32]). However, this could be due to a selection bias. In fact, young age of onset of CKD may have prompted clinicians to refer these patients for genetic testing despite negative family history, whereas older patients with possible ADTKD-MUC1 and no family history of kidney disease might be presumed to have another etiology of CKD. One way to confirm this would be to test a large cohort of patients with CKD from unknown etiology with no family history of CKD. Considering the nonspecific clinical manifestations of ADTKD-MUC1 and the phenotypic variability, it has previously been suggested that the most important clue to diagnosis is the presence of CKD in first-degree family. The possibility of de novo cases makes the clinical diagnosis of ADKTD-MUC1 even more challenging. Conclusion With VNtyper, we were able to diagnose new cases of ADTKD-MUC1 in a large cohort of patients with various phenotypes, with a significant prevalence of 1.2%. ADTKD-MUC1 was not suspected in 30% of these patients who would have maybe never been diagnosed otherwise. This is also the first study in which we describe a proven de novo case of ADTKD-MUC1. Pathogenic variants in the MUC1 gene should thus be in the differential diagnosis of all unspecified CKD, even if there is no family history since de novo variants are also possible.

#2062 Protein interactome and trafficking of uromodulin in HEK and MDCK cell model

Abstract Background and Aims Uromodulin (UMOD) is a kidney-specific glycoprotein and the most abundant urinary protein in healthy individuals. Genome-wide association studies have shown an association between UMOD variants, kidney diseases, and hypertension. UMOD exhibits bidirectional secretion as it releases into the renal interstitium and circulation. However, the molecular trafficking of UMOD and its interaction remains poorly defined. We aimed to establish a stable Human Embryonic Kidney (HEK293) cell line expressing human UMOD to identify the potential regulators of UMOD expression or secretion. This study will provide significant implications for conditions such as hypertension, chronic kidney diseases, acute kidney injury, or UMOD-autosomal dominant tubulointerstitial kidney disease (UMOD-ADTKD). Method A HEK-UMOD-expressing cell line was generated by introducing human UMOD transcript 1 expression and using a tetracycline-inducible expression vector (pcDNA™FRT⁄TO vector) with yellow fluorescent protein tag at the C-terminal and previously established MDCK-UMOD cell line was also used. An untargeted proteomic approach was used to identify proteins, using GFP trap co-immunoprecipitation assay followed by mass spectrometry analysis. Results We identified 1367 and 1140 UMOD interacting proteins in HEK and MDCK cell models respectively. There were 620 proteins common to both these models. Through gene ontology, we unravel the molecular mechanisms involved in the biosynthesis, folding, and transport of UMOD. We observed several proteins associated with clathrin-mediated transporting. To study the role of clathrin in UMOD transport, we treated the polarised MDCK-UMOD cells with pitstop 2. There was significantly more secretion of UMOD with pitstop 2 treatment in the apical compartment compared to untreated cells however there was no significant difference in UMOD secretion in the basolateral compartment. Conclusion These results suggested that clathrin-coated vesicles are involved in transporting and sorting UMOD. Further studies need to investigate the functional importance of these proteins in UMOD trafficking and their implications in different physiological processes.

#2606 Clinically boosted exome-sequencing is necessary for accurate and highly sensitive genetic diagnosis of ADTKD-MUC1

Abstract Background and Aims The human genome includes tandem repeats with variable length (VNTR) and a subset of these repeats have been associated with rare human diseases. Specific frameshift variants in the coding-VNTR of the MUC1 gene cause autosomal dominant tubulointerstitial kidney disease—MUC1 (ADTKD-MUC1). Calling variants from VNTR using short-read sequencing (SRS) is challenging due to poor read mappability, motif complexity (34*60-mer motifs are known up to now), variable repetition, and enormous motif sequence similarity. We have recently developed a computational pipeline called VNtyper, tailored for the precise detection of disease-causing variants within the MUC1 VNTR region using short-read sequencing data. This advancement allowed us to identify overlooked cases in a hereditary renal disease registry, leading to the diagnosis of at least 40 patients. Given that regular exome sequencing with low VNTR coverage proved inefficient for VNtyper, our focus shifted to boost the capture of MUC1 VNTR in exome. This improvement aims to enable the application of VNtyper in ADTKD-MUC1 diagnosis through exome sequencing. Method VNtyper utilizes two independent genotyping algorithms (Kestrel and code-adVNTR) along with MUC1 VNTR-specific reference sequence for the variant detection and is sensitive to the VNTR coverage. We employ Twist custom panels with v1 protocol for target enrichment in both our panel and exome sequencing. This procedure allows for the inclusion of spike-in probes without interfering with other targets. We designed an NTI panel that specifically targets 6 genes associated with ADTKD, including UMOD, MUC1, HNF1B, REN, SEC61A1, and DNAJB11. These genes were captured using a 1x tiling approach, whereas the MUC1 VNTR region was captured with 4x tiling approach. During the exome target enrichment process, we included the NTI probes as a spike-in to boost VNTR coverage. We conducted a routine exome sequencing on a total of 6 samples, consisting of 3 positive controls and 3 negative controls. Additionally, we conducted 16 boosted exome, using 3 negative controls and 13 MUC1 positive samples. Prior to using VNtyper on both exomes, we conducted initial quality controls to verify that there were no alterations in the coverages of other genes. Results The mean coverage of MUC1 VNTR in the regular exome was 72.1x, while in the boosted exome, it exhibited a significant increase to 144x. Adding spike in probes did not have significant effect on the coverage of the contig and there was no alteration in ratio of heterozygosity. As anticipated, in the regular exome, VNtyper was unsuccessful in identifying pathogenic variation in 2 out of 3 true positives. However, all negative controls tested negative. When we used the enhanced exome, we accurately identified all 13 true positive cases, while the negative control cases stayed negative. Through downsampling experiments (reducing read depth from 50% to 5% of the total) on panel data with a mean coverage of 700x, we determined that coverage below 100 should be considered as low coverage for VNTR genotyping using our pipeline. This underscores the critical importance of maintaining adequate coverage for accurate and reliable VNTR genotyping. Conclusion We have achieved successful enhancements in the accuracy and sensitivity of ADTKD diagnosis through the application of VNtyper on clinically boosted exome data. While VNtyper could identify MUC1-positive patients in regular exome data, the effectiveness is influenced by the number of repeats in both alleles and the specific motif in which the variation is present, which significantly decreases the sensitivity. In summary, the VNtyper pipeline demonstrates its ability to detect pathogenic variations in ADTKD-MUC1 on panel data (100% sensitivity), and the improvement in VNTR capture in exome significantly enhances the sensitivity of the ADTKD diagnosis.

#1760 Four cases of ADTKD: AFM analysis of urine sediment

Abstract Background and Aims Autosomal Dominant Tubulointerstitial kidney disease (ADTKD) is a rare disease (16 per million), associated with CV events, hypertension, and gout. ADTKD is characterized by interstitial fibrosis, tubular atrophy, microcysts, and progressive CKD. We describe a case of a family with clinical characteristics of ADTKD and provide for the first time a characterization of their urinary sediment. Given the tendency of a specific type of ADTKD caused by UMOD mutation to form tubular crystals, we have also tested the ability of the urine from ADTKD patients to precipitate and form crystals in vitro. Method We examined clinical features and urinary sediment of a family with ADTKD: a 51 years old woman with CKD (eGFR 30 mL/min/1.73 m2, CDK-EPI 2021) and her three sons, a 20 years old male, two daughters of 26 and 24 years old, all with hyperuricemia. Genetic analysis is not yet available. The test of urine precipitation consisted of the analysis of crystals after air-drying a thin layer of urine after enrichment of the organic quota by triple centrifugation for 10 minutes at 1000 rpm. Urinary sediments were also studied by Atomic Force Microscopy (ICSPI nGauge AFM) to achieve a resolution of 20 nm of crystals. Results Clinical data for the four patients are reported in the table. None of the patients showed proteinuria. The urine sediment of all patients showed rare WBC (in greater amounts only in patient 1), rare amorphous granular casts, and rare tubular cells. Three patients showed formations of variably sized crystals in vitro. The precipitation test did not show crystals in patient 1, whereas patients 2-3 showed several rosette-type crystals often with a wagon-wheel concentric contour which resembled leucine crystals or CaCO3. Adding formalin to the samples resulted in a more clear organization of crystals in wagon-wheel structures. AFM imaging of the crystals showed rod-like structures branching with an angle of 35°. Conclusion ADTKD remains a poorly understood genetic condition with no specific treatment options. Our data suggest that patients with this condition may have an enhanced tendency to form crystals in vitro. Speculatively, this might induce tubular injury in vivo. Data from UMOD-ko animal models showed intrarenal crystals (not better specified). Genetic alterations of branched aminoacids metabolism (such as leucine in Maple syrup disease) can also cause tubular diseases, although the systemic manifestations are very different from our patients. Genetic analysis of our family will give further information on the proteins involved in these crystal structures.

#1061 Brucella infection in a patient with renal cystic disease and renal imaging changes before and after treatment: a case report

Abstract Background and Aims Brucellosis can affect nearly all systems. Genitourinary involvement is uncommon in patients with brucellosis, accounting for approximately 10% of cases. We diagnosed a rare case of renal cysts with brucellosis and reported renal imaging changes before and after treatment. Method A 38-year-old man was admitted to our hospital in September 2021 with complaints of elevated serum creatinine, proteinuria for more than 2 months, and intermittent fever for 2 weeks. In July 2020, the patient experienced fatigue, and a rash on all four extremities. He denied experiencing low back pain or joint swelling. Urine analysis revealed the following: BLD (+), Pro (+), 24-hour urine protein (24 h UP) 0.7 g; blood: Cr 11.88 mg/dL, UA 77.51 mg/dL, ALP 217 IU/L, and GGT 227 IU/L. MRI revealed multiple small punctate areas with short T1 signals in both kidneys and splenomegaly. Soon, he experienced persistent afternoon fever with a maximum temperature of 39.0°C, along with night sweats and left lumbar pain. There were no symptoms of cough, expectoration, or urinary tract irritation. The patient had diabetes mellitus and diabetic retinopathy. He has lived in the Inner Mongolia Autonomous Region. He denied having any contact with raw milk or mice. His father and sister had kidney disease and diabetes. In September 2021, the patient was admitted to our hospital. Urinalysis revealed BLD (-), Pro 0.3 g/L, and 24 hUP 1.39 g; blood: HGB 117 g/L, ALP 227 U/L, GGT 221 U/L, Cr 2.56 mg/dL, UA 88.79 mg/dL, and K 3.2 mEq/L. The infection indicators were as follows: the standard tube agglutination test (+) (Fig. 1), Brucella (+) in blood culture, a positive qualitative test for blood cryptococcal antigen and qualitative positive results for 6 Cryptococcus neoformans sequences in bronchoalveolar lavage fluid using next-generation sequencing. Ultrasound showed multiple cysts in both kidneys. It also showed uneven echogenicity in the left testis and visible lymph nodes in the left neck, bilateral axillae and groin. CT revealed cavitary nodules and ground-glass opacities in the right middle lobe, as well as splenomegaly. MRI revealed renal cysts (Fig. 2a, b, c) and abscesses (Fig. 2e, f, g). The patient was diagnosed with stage 3 chronic kidney disease (CKD), pulmonary cryptococcosis, and brucellosis associated with renal abscess, left orchitis, splenomegaly, multiple lymphadenopathies, rash, and hyperuricemia. Doxycycline, rifampicin, and fluconazole were administered. He had no fever, his low back pain had disappeared, and his rash were relieved. Results A reexamination after 2 months revealed the following: the urinalysis results revealed a BLD (-), Pro(-), and 24 hUP 0.15 g; blood: GGT 107 IU/L; ALP 72 IU/L; Cr 1.89 mg/dL; UA 0.22 mg/dL; and K 4.0 mEq/L. Ultrasound revealed a decrease in the size of the spleen. MRI revealed the liquefaction of renal abscesses. Brucella therapy has been found to be effective. Conclusion The patient was a young man who was infected with both Brucella and Cryptococcus. Although his hometown was in an area affected by an epidemic, his current residence was not affected. Namely, he was immunocompromised, which was associated with diabetes. After receiving anti-Brucella treatment, his symptoms disappeared, the renal abscess liquefied, but creatinine decreased to levels similar to those at onset without a decreasing trend. These findings suggest that the patient had underlying CKD that was not associated with Brucellosis. We believe that the CKD was diabetes and renal cysts. He had hyperuricemia, hypomagnesaemia, unexplained asymptomatic abnormal liver function, and mild proteinuria. Imaging indicated the presence of renal cysts. In addition to having diabetes, he had a family history of kidney disease and diabetes. We diagnosed the patient with CKD and as having autosomal dominant tubulointerstitial disease (ADTKD) associated with the HNF1B pathogenic gene mutation. This gene mutation is also rare in ADTKD patients. Genetic testing revealed that the causative genes include NM001303448. Potential causative genes included NM000128. The mutated genes mentioned above are not typical causative genes for HNF1B or other types of ADTKD.

#276 ADTKD genetic diagnostics in Europe: where do we stand and what is needed?

Abstract Background and Aims We are the first European patient organization to pursue the goal of raising awareness of the monogenic kidney disease ADTKD (autosomal dominant tubulointerstitial kidney disease) and supporting its research (www.adtkd.de/en-gb). To date, causative mutations are known in at least five disease genes (UMOD, MUC1, REN, HNF1B, SEC61A1) [1] and one can expect that even more disease genes exist. There are already strong international collaborations to define the clinical course of ADTKD [2] and to evaluate a targeted therapy in clinical trials [3]. Clinical registries form the basis for the inclusion of patients, preferably at an early stage of the disease. Such a registry already exists in the USA and is currently being established in Europe (ADTKD-Net) as part of the European Joint Program on Rare Diseases (EJP RD). Due to its non-specific and variable clinical characteristics, ADTKD is often misdiagnosed or not diagnosed at all. Experts therefore suspect a high number of unreported cases. There are also challenges in genetic diagnostics. While next generation sequencing (NGS) panels have been established for ADTKD, they are usually unable to detect pathogenic MUC1 variants due to their specific location in the genome. This is the insertion of an additional cytosine (dupC) in a VNTR (Variable Number of Tandem Repeats) domain of the MUC1 gene, which cannot be detected by NGS and therefore requires special procedures such as SnaPshot Minisequencing [4] or VNtyper [5]. For instance, there are only two laboratories that can perform this specific MUC1 testing in Germany to date. The aim of this study is to assess the status quo of ADTKD diagnostics in Europe. We hypothesize that there is a lack of appropriate structures to adequately and reliably diagnose ADTKD, notably ADTKD-MUC1. The study is intended to help identify deficits and obstacles in order to address these in a targeted manner. Methods We used Survey Monkey to create a digital survey, which we sent by email to around 50 European ADTKD experts. They were asked to answer 7 key questions (Fig. 1). For the selection of suitable ADTKD experts, we use various sources such as publications on ADTKD in PubMed, the Expert Finder and the European Patient Advocacy Groups (ePAG) in the European Reference Network for Rare Kidney Diseases (ERKNet) and our own network. Our aim is to cover at least the 30 largest countries in Europe in terms of population. Results Results will be presented at the ERA conference. Conclusion With our survey we would like to substantiate the hypothesis that the possibilities of molecular diagnostics of ADTKD in Europe are currently insufficient. Based on our results, short and long-term measures should be taken to remedy potential deficits so that as many patients as possible can be identified and have access to therapeutic options in the future. Another interesting aspect is the awareness of ADTKD among European nephrologists. This could be a future activity of our patient organization.

Clinical Case of Mild Tatton–Brown–Rahman Syndrome Caused by a Nonsense Variant in DNMT3A Gene

Tatton–Brown–Rahman syndrome is a rare autosomal dominant hereditary disease caused by pathogenic variants in the DNMT3A gene, which is an important participant in epigenetic regulation, especially during embryonic development, and is highly expressed in all tissues. The main features of the syndrome are high growth, macrocephaly, intellectual disability, and facial dysmorphic features. We present a clinical case of Tatton–Brown–Rahman syndrome in a ten-year-old boy with macrocephaly with learning difficulties, progressive eye impairment, and fatigue suspected by a deep learning-based diagnosis assistance system, Face2Gene. The proband underwent whole-exome sequencing, which revealed a recurrent nonsense variant in the 12th exon of the DNMT3A, leading to the formation of a premature stop codon—NM_022552.5:c.1443C>A (p.Tyr481Ter), in a heterozygous state. This variant was not found in parents, confirming its de novo status. The patient case described here contributes to the understanding of the clinical diversity of Tatton–Brown–Raman syndrome with a mild clinical presentation that expands the phenotypic spectrum of the syndrome. We report the first recurrent nonsense variant in the DNMT3A gene, suggesting a mutational hot-spot. Differential diagnoses of this syndrome with Sotos syndrome, Weaver syndrome, and Cowden syndrome, as well as molecular confirmation, are extremely important, since the presence of certain types of pathogenic variants in the DNMT3A gene significantly increases the risk of developing acute myeloid leukemia.

Causative role of a novel intronic indel variant in FBN1 and maternal germinal mosaicism in Marfan syndrome

BackgroundMarfan syndrome (MFS) is an autosomal dominant connective tissue disease with wide clinical heterogeneity, and mainly caused by pathogenic variants in fibrillin-1 (FBN1).MethodsA Chinese 4-generation MFS pedigree with 16 family members was recruited and exome sequencing (ES) was performed in the proband. Transcript analysis (patient RNA and minigene assays) and in silico structural analysis were used to determine the pathogenicity of the variant. In addition, germline mosaicism in family member (Ι:1) was assessed using quantitative fluorescent polymerase chain reaction (QF-PCR) and short tandem repeat PCR (STR) analyses.ResultsTwo cis-compound benign intronic variants of FBN1 (c.3464–4 A > G and c.3464-5G > A) were identified in the proband by ES. As a compound variant, c.3464-5_3464-4delGAinsAG was found to be pathogenic and co-segregated with MFS. RNA studies indicated that aberrant transcripts were found only in patients and mutant-type clones. The variant c.3464-5_3464-4delGAinsAG caused erroneous integration of a 3 bp sequence into intron 28 and resulted in the insertion of one amino acid in the protein sequence (p.Ile1154_Asp1155insAla). Structural analyses suggested that p.Ile1154_Asp1155insAla affected the protein’s secondary structure by interfering with one disulfide bond between Cys1140 and Cys1153 and causing the extension of an anti-parallel β sheet in the calcium-binding epidermal growth factor-like (cbEGF)13 domain. In addition, the asymptomatic family member Ι:1 was deduced to be a gonadal mosaic as assessed by inconsistent results of sequencing and STR analysis.ConclusionsTo our knowledge, FBN1 c.3464-5_3464-4delGAinsAG is the first identified pathogenic intronic indel variant affecting non-canonical splice sites in this gene. Our study reinforces the importance of assessing the pathogenic role of intronic variants at the mRNA level, with structural analysis, and the occurrence of mosaicism.

TRIM37 is a primate-specific E3 ligase for Huntingtin and accounts for the striatal degeneration in Huntington's disease.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disease characterized by preferential neuronal loss in the striatum. The mechanism underlying striatal selective neurodegeneration remains unclear, making it difficult to develop effective treatments for HD. In the brains of nonhuman primates, we examined the expression of Huntingtin (HTT), the gene responsible for HD. We found that HTT protein is highly expressed in striatal neurons due to its slow degradation in the striatum. We also identified tripartite motif-containing 37 (TRIM37) as a primate-specific protein that interacts with HTT and is selectively reduced in the primate striatum. TRIM37 promotes the ubiquitination and degradation of mutant HTT (mHTT) in vitro and modulates mHTT aggregation in mouse and monkey brains. Our findings suggest that nonhuman primates are crucial for understanding the mechanisms of human diseases such as HD and support TRIM37 as a potential therapeutic target for treating HD.

NF1 with 47,XYY mosaicism diagnosed by mandibular neurofibromas.

Neurofibromatosis type 1 (NF1) is an autosomal dominant nevus disease characterized by multiple manifestations, primarily café-au-lait macules and neurofibromas. Here, we present the case of an NF1 patient with 47,XYY mosaicism whose diagnosis was prompted by café-au-lait macules on the skin and mandibular neurofibromas. Targeted next-generation sequencing of the patient's blood sample revealed a novel frameshift mutation in NF1 (NM_000267.3:c.6832dupA:p.Thr2278Asnfs*8) that is considered a pathogenic variant.

Multiple endocrine neoplasia type 2B diagnosed after small intestinal volvulus with progressive megacolon in an adolescent.

Multiple endocrine neoplasia type 2B is a rare autosomal dominant disease characterized by the presence of medullary thyroid carcinoma, pheochromocytoma, Marfan-like fatigue, a peculiar face with thickening of the lips, mucosal neuromas on the lips and tongue, and gastrointestinal phenomena. Most patients harbor pathological variants of the RET gene. Herein, we present the first case of a 14year-old boy who experienced small intestinal volvulus along with a megacolon, and he was diagnosed with multiple endocrine neoplasia type 2B. The patient complained of constipation since he was 2years old and slowly progressive abdominal distension at school age. At 14years of age, he presented with remarkable megacolon mimicking Hirschsprung's disease and complicated with small intestinal volvulus. The volvulus was successfully repaired, and the particularly dilated transverse colon was resected following a rectal biopsy. Histopathological evaluation of the resected transverse colon revealed to be compatible with ganglioneuromatosis. After emergency surgery, the patient was diagnosed with multiple endocrine neoplasia type 2B with medullary thyroid carcinoma, and a de novo variant of RET was confirmed. Gastroenterologists should consider it when treating patients with constipation, especially those with megacolon. Therefore, timely diagnosis may lead to appropriate treatment of medullary thyroid carcinoma and improve mortality.

Comprehensive genetic analysis of facioscapulohumeral muscular dystrophy by Nanopore long-read whole-genome sequencing

BackgroundFacioscapulohumeral muscular dystrophy (FSHD) is a high-prevalence autosomal dominant neuromuscular disease characterized by significant clinical and genetic heterogeneity. Genetic diagnosis of FSHD remains a challenge because it cannot be detected by standard sequencing methods and requires a complex diagnosis workflow.MethodsWe developed a comprehensive genetic FSHD detection method based on Oxford Nanopore Technologies (ONT) whole-genome sequencing. Using a case–control design, we applied this procedure to 29 samples and compared the results with those from optical genome mapping (OGM), bisulfite sequencing (BSS), and whole-exome sequencing (WES).ResultsUsing our ONT-based method, we identified 59 haplotypes (35 4qA and 24 4qB) among the 29 samples (including a mosaic sample), as well as the number of D4Z4 repeat units (RUs). The pathogenetic D4Z4 RU contraction identified by our ONT-based method showed 100% concordance with OGM results. The methylation levels of the most distal D4Z4 RU and the double homeobox 4 gene (DUX4) detected by ONT sequencing are highly consistent with the BSS results and showed excellent diagnostic efficiency. Additionally, our ONT-based method provided an independent methylation profile analysis of two permissive 4qA alleles, reflecting a more accurate scenario than traditional BSS. The ONT-based method detected 17 variations in three FSHD2-related genes from nine samples, showing 100% concordance with WES.ConclusionsOur ONT-based FSHD detection method is a comprehensive method for identifying pathogenetic D4Z4 RU contractions, methylation level alterations, allele-specific methylation of two 4qA haplotypes, and variations in FSHD2-related genes, which will all greatly improve genetic testing for FSHD.

Consanguinité et son impact sur la santé et la dynamique du génome : Un exemple de la Tunisie

The genetic disease spectrum in Tunisia arises from the founder effect, genetic drift, selection, and consanguinity. The latter represents a deviation from panmixia, characterized by a non-random matrimonial choice that may be subject to several rules, such as socio-cultural, economic, or other factors. This shifts the genetic structure away from the Hardy-Weinberg equilibrium, increasing homozygous genotypes and decreasing heterozygotes, thus raising the frequency of autosomal recessive diseases. Similar to other Arab populations, Tunisia displays high consanguinity rates that vary geographically. Approximately 60% of reported diseases in Tunisia are autosomal recessive, with consanguinity possibly occurring in 80% of families for a specific disease. In inbred populations, consanguinity amplifies autosomal recessive disease risk, yet it does not influence autosomal dominant disease likelihood but rather impacts its phenotype. Consanguinity is also suggested to be a major factor in the homozygosity of deleterious variants leading to comorbid expression. At the genome level, inbred individuals inherit homozygous mutations and adjacent genomic regions known as runs of homozygosity (ROHs). Short ROHs indicate distant inbreeding, while long ROHs refer to recent inbreeding. ROHs are distributed rather irregularly across the genome, with certain short regions featuring an excess of ROH, known as ROH islands. In this review, we discuss consanguinity's impact on population health and genome dynamics, using Tunisia as a model.

Efficacy and safety of Piwei Peiyuan Prescription in the treatment of chronic atrophic gastritis: A multicenter, double-blind, double-simulated, randomized, controlled clinical trial.

The incidence of chronic atrophic gastritis (CAG) is on the rise due to the growing pressure in modern social life, increasing bad living habits and emotional disorders (such as anxiety and depression), and the aging of the population. Of note, digestive system diseases are the dominant diseases in the field of traditional Chinese medicine (TCM). Therefore, this study evaluated the efficacy and safety of Piwei Peiyuan Prescription, a TCM prescription, in the treatment of CAG through a multicenter, double-blind, randomized, controlled design. This research was organized by the Second Affiliated Hospital of Anhui University of TCM and simultaneously performed in 6 centers. A total of 120 CAG patients were included and randomized into 2 groups: group A (treatment with Piwei Peiyuan granules plus Weifuchun Simulant) and Group B (treatment with Weifuchun Tablets plus Piwei Peiyuan Simulant). These 2 groups were compared in terms of gastroscopy scores, TCM syndrome scores, and serological indicators at baseline and within 12 weeks after treatment. According to endoscopic biopsy for pathological observation, atrophy (2.56 ± 1.08 vs 3.00 ± 1.00, P = .028) and intestinal epithelial hyperplasia (1.00 ± 1.43 vs 1.69 ± 1.80, P = .043) scores were lower in group A than in group B. For the more, group A had higher effective rates for inflammation, atrophy, and intestinal metaplasia (IM) in various regions of the stomach, especially for atrophy/IM of the gastric angle (64%, P = .034) and atrophy/IM of the lesser curvature of gastric antrum (63%, P = .042) than group B. According to TCM syndrome scores, Piwei Peiyuan Prescription improved the scores of gastric distension (2.30 ± 1.13 vs 2.80 ± 0.99, P = .022), preference for warmth and pressure (1.44 ± 1.06 vs 1.36 ± 1.10, P = .041), and poor appetite and indigestion (0.78 ± 0.66 vs 1.32 ± 0.72, P = .018). GAS, MTL, and PGE2 expression was significantly elevated after treatment with Piwei Peiyuan Prescription (P < .001). Piwei Peiyuan Prescription is effective for CAG treatment with high safety.

Blood flow regulates acvrl1 transcription via ligand-dependent Alk1 activity.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease characterized by the development of arteriovenous malformations (AVMs) that can result in significant morbidity and mortality. HHT is caused primarily by mutations in bone morphogenetic protein receptors ACVRL1/ALK1, a signaling receptor, or endoglin (ENG), an accessory receptor. Because overexpression of Acvrl1 prevents AVM development in both Acvrl1 and Eng null mice, enhancing ACVRL1 expression may be a promising approach to development of targeted therapies for HHT. Therefore, we sought to understand the molecular mechanism of ACVRL1 regulation. We previously demonstrated in zebrafish embryos that acvrl1 is predominantly expressed in arterial endothelial cells and that expression requires blood flow. Here, we document that flow dependence exhibits regional heterogeneity and that acvrl1 expression is rapidly restored after reinitiation of flow. Furthermore, we find that acvrl1 expression is significantly decreased in mutants that lack the circulating Alk1 ligand, Bmp10, and that, in the absence of flow, intravascular injection of BMP10 or the related ligand, BMP9, restores acvrl1 expression in an Alk1-dependent manner. Using a transgenic acvrl1:egfp reporter line, we find that flow and Bmp10 regulate acvrl1 at the level of transcription. Finally, we observe similar ALK1 ligand-dependent increases in ACVRL1 in human endothelial cells subjected to shear stress. These data suggest that ligand-dependent Alk1 activity acts downstream of blood flow to maintain or enhance acvrl1 expression via a positive feedback mechanism, and that ALK1 activating therapeutics may have dual functionality by increasing both ALK1 signaling flux and ACVRL1 expression.

The vestibular symptomatology of Machado-Joseph Disease.

Machado Joseph Disease (MJD) is an autosomal dominant neurodegenerative disease. In previous studies, we described significant bilateral horizontal Vestibulo-Ocular Reflex (VOR) deficit within this population without any reference to the presence of vestibular symptomatology. To evaluate whether, beyond cerebellar ataxia complaints, MJD patients have typical vestibular symptomatology corresponding to the accepted diagnostic criteria of Bilateral Vestibulopathy (BVP) according to the definition of the International Barany Society of Neuro-Otology. Twenty-one MJD, 12 clinically stable chronic Unilateral Vestibulopathy (UVP), 15 clinically stable chronic BVP, and 22 healthy Controls underwent the video Head Impulse Test (vHIT) evaluating VOR gain and filled out the following questionnaires related to vestibular symptomatology: The Dizziness Handicap Inventory (DHI), the Activities-specific Balance Confidence Scale (ABC), the Vertigo Visual Scale (VVS) and the Beck Anxiety Inventory (BAI). The MJD group demonstrated significant bilateral vestibular impairment with horizontal gain less than 0.6 in 71% of patients (0.54±0.17). Similar to UVP and BVP, MJD patients reported a significantly higher level of symptoms than Controls in the DHI, ABC, VVS, and BAI questionnaires. MJD demonstrated significant VOR impairment and clinical symptoms typical of BVP. We suggest that in a future version of the International Classification of Vestibular Disorders (ICVD), MJD should be categorized under a separate section of central vestibulopathy with the heading of bilateral vestibulopathy. The present findings are of importance regarding the clinical diagnosis process and possible treatment based on vestibular rehabilitation.