Pathological Mutations Research Articles

Abstract #988443: Primary Hyperparathyroidism and Persistent Peptic Ulcers: A Prelude to a Diagnosis of MEN1 Caused by a Novel Gene Mutation

Multiple Endocrine Neoplasia 1 (MEN1) is a rare syndrome characterized by a propensity for pituitary, parathyroid, pancreatic, and adrenal tumors. Over 200 pathologic mutations have been reported. Penetrance is high, but presentation can be variable making its diagnosis at times difficult.

Clinical characteristics and prognostic value of the KRAS mutation in Chinese colorectal cancer patients.

The KRAS mutations are high-frequency somatic mutations found in colorectal cancer patients from Western and Asian countries however, with the exception of exon 2 of KRAS, other prevalence and prognostic values have not been adequately assessed in Asian patients. The aim of this study was to determine the mutation frequencies of whole exon mutations of KRAS in Chinese colorectal cancer patients and to investigate their impact on prognosis. A total of 7189 tumor tissue samples (iCohort) were subjected to next-generation sequencing for detection of KRAS mutations. All pathologic or likely pathologic mutations of KRAS were considered. In addition, clinical features and prognostic dates were collected from 145 patients at The Third Affiliated Hospital of Soochow University, China (sCohort) and used droplet digital™ polymerase chain reaction to detect KRAS mutations. In the iCohort, 2706 patients (37.6%) were confirmed harboring KRAS mutations. The most frequent of these mutations were G12D (32.19%), G12V (17.96%), and G13D (17.59%). In the sCohort, 51 colorectal cancer patients (35.17%) had KRAS mutations, among which KRAS G12D (64.71%), G13D (29.41%), and G14D (3.92%) were high-frequency. The KRAS mutations were associated with shorter median overall survival than wild-type tumors (69 vs. 55 months; HR 1.80; 95% Cl 1.22, 2.64; P=0.0003). In the Cox multivariate analysis, age (HR 1.562; 95% Cl 1.10, 2.22; P=0.013), tumor differentiation (HR 0.417; 95% Cl 0.19, 0.90; P=0.026), and KRAS mutation (HR 1.897; 95% Cl 0.19, 0.90; P=0.001) remained independent predictors of shorter overall survival. Among the common KRAS mutations, G12D was significantly associated with shorter overall survival (HR 2.17; 95% Cl 1.31, 3.58; P < 0.0001) compared with KRAS wild-type patients. Our findings indicate that KRAS genes are frequently mutated, and over 30% harbored the KRAS G12D mutation subtype. We found that the KRAS G12D mutation is associated with inferior survival and is a biomarker of poor prognosis in Chinese patients. Our data emphasize the importance of molecular features in colorectal cancer patients, which could potentially be improved by G12D-specific related inhibitors.

High expression of PARD3 predicts poor prognosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most commonly cancers with poor prognosis and drug response. Identifying accurate therapeutic targets would facilitate precision treatment and prolong survival for HCC. In this study, we analyzed liver hepatocellular carcinoma (LIHC) RNA sequencing (RNA-seq) data from The Cancer Genome Atlas (TCGA), and identified PARD3 as one of the most significantly differentially expressed genes (DEGs). Then, we investigated the relationship between PARD3 and outcomes of HCC, and assessed predictive capacity. Moreover, we performed functional enrichment and immune infiltration analysis to evaluate functional networks related to PARD3 in HCC and explore its role in tumor immunity. PARD3 expression levels in 371 HCC tissues were dramatically higher than those in 50 paired adjacent liver tissues (p < 0.001). High PARD3 expression was associated with poor clinicopathologic feathers, such as advanced pathologic stage (p = 0.002), vascular invasion (p = 0.012) and TP53 mutation (p = 0.009). Elevated PARD3 expression also correlated with lower overall survival (OS, HR = 2.08, 95% CI = 1.45–2.98, p < 0.001) and disease-specific survival (DSS, HR = 2.00, 95% CI = 1.27–3.16, p = 0.003). 242 up-regulated and 71 down-regulated genes showed significant association with PARD3 expression, which were involved in genomic instability, response to metal ions, and metabolisms. PARD3 is involved in diverse immune infiltration levels in HCC, especially negatively related to dendritic cells (DCs), cytotoxic cells, and plasmacytoid dendritic cells (pDCs). Altogether, PARD3 could be a potential prognostic biomarker and therapeutic target of HCC.

Cohort Generation and Characterization of Patient-Specific Familial Hypercholesterolemia Induced Pluripotent Stem Cells.

Homozygous familial hypercholesterolemia (hoFH) is a rare disorder caused primarily by pathological mutations in the low-density lipoprotein receptor (LDLR), which disrupts LDL-cholesterol (LDL-C) metabolism homeostasis. hoFH patients are at extremely high risk for cardiovascular disease and are resistant to standard therapies. LDLR knockout animals and in vitro cell models overexpressing different mutations have proved useful, but may not fully recapitulate human LDLR mutation biology. We and others have generated induced pluripotent stem cells (iPSC) from hoFH patient's fibroblasts and T cells and demonstrated their ability to recapitulate hoFH biology. In this study, we present the generation and characterization of a cohort of seven hoFH-iPSC lines derived from peripheral blood mononuclear cells (PBMC) collected from four homozygous and three compound heterozygous patients. The hoFH-iPSC cohort demonstrated a wide range of LDLR expression and LDL-C internalization in response to rosuvastatin that correlated with the predicted pathogenicity of the mutation. We were able to confirm that hoFH-iPSC cohort were pluripotent by differentiation toward all three germ layers and specifically to hepatocyte-like cells (HLC), the cell with primary LDL-C metabolic regulatory control, by expression of hepatocyte markers. hoFH patient PBMC-derived iPSC recapitulate the LDLR dysfunction of their specific mutation. They were capable of differentiating to HLC and could be useful for early developmental studies, pharmacology/toxicology, and potentially autologous cell therapy.

Imprecise Medicine: BRCA2 Variants of Uncertain Significance (VUS), the Challenges and Benefits to Integrate a Functional Assay Workflow with Clinical Decision Rules.

Pathological mutations in homology-directed repair (HDR) genes impact both future cancer risk and therapeutic options for patients. HDR is a high-fidelity DNA repair pathway for resolving DNA double-strand breaks throughout the genome. BRCA2 is an essential protein that mediates the loading of RAD51 onto resected DNA breaks, a key step in HDR. Germline mutations in BRCA2 are associated with an increased risk for breast, ovarian, prostate, and pancreatic cancer. Clinical findings of germline or somatic BRCA2 mutations in tumors suggest treatment with platinum agents or PARP inhibitors. However, when genetic analysis reveals a variant of uncertain significance (VUS) in the BRCA2 gene, precision medicine-based decisions become complex. VUS are genetic changes with unknown pathological impact. Current statistics indicate that between 10–20% of BRCA sequencing results are VUS, and of these, more than 50% are missense mutations. Functional assays to determine the pathological outcome of VUS are urgently needed to provide clinical guidance regarding cancer risk and treatment options. In this review, we provide a brief overview of BRCA2 functions in HDR, describe how BRCA2 VUS are currently assessed in the clinic, and how genetic and biochemical functional assays could be integrated into the clinical decision process. We suggest a multi-step workflow composed of robust and accurate functional assays to correctly evaluate the potential pathogenic or benign nature of BRCA2 VUS. Success in this precision medicine endeavor will offer actionable information to patients and their physicians.

A Multifocal Paraganglioma in an African Male Due to an Underlying SDHB Mutation

Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumors arising from adrenal and extra-adrenal paraganglia. Up to forty percent are due to an underlying germline mutation. Mutations in the subunit B gene of the SDH complex (SDHB) are associated with PGL syndrome four. A 34-yr-old African man from Southern Africa presented with a two-year history of sustained hypertension associated with the classic triad of sweating, headaches and palpitations. Family history was contributory towards early unexpected deaths of his father (age 42) and two younger brothers (ages 13 and 14 respectively). On examination his blood pressure was persistently elevated measuring 146/87mmHg. In view of the classic presenting symptoms and hypertension onset at a young age, a PPGL was suspected. Biochemical investigations were positive with an elevated 24-hour urine normetanephrine level of 35807 (480-2424nmol/24hours), normal metanephrine level of 689 (264-1729nmol/24hours), an elevated normetanephrine:creatinine ratio of 3270 (28-158nmol/mmol creatinine) and an elevated methoxytyramine level 4941.69nmol/24 hours (<800nmol/24 hours). Computed tomography of the abdomen and neck revealed a homogenous soft tissue mass measuring 5.9cm x 3.6cm x 6.6cm anterior to the right kidney and separate from the right adrenal gland and a carotid body tumor measuring 3.6cm x 2.9cm x 4.1cm. Both were radio-avid on a [68Gallium]-DOTATATE-Positron Emission Tomography (PET)-CT. There were no features to suggest metastatic disease. Genetic testing is not available in South Africa; therefore, testing was done at an international laboratory. This revealed a pathological SDHB mutation variant, c.724C>A p.(Arg242Ser) and hence PGL4 syndrome. The patient underwent staged surgery with successful removal of the intra-abdominal tumor. Unfortunately, due to peri-operative complications associated with the second surgery, the patient demised. Histopathological examination of both tumors was consistent with a paraganglioma. Genetic counselling and testing were offered to all living first-degree relatives. His sister tested positive for the same pathological variant. His 6-week-old son will be offered counselling and testing at a later stage. To the best of our knowledge, we are the first to describe the missense SDHB mutation (pathogenic variant c.724C>A p.[Arg242Ser]) and the occurrence of an SDHB associated PGL in a family of African ethnicity. This case highlights the importance of genetic counselling and testing in patients with a confirmed PPGL. Due to resource limitation the African population remains under represented in genetic studies which limits the utility of precision medicine in this group. As such, our case is an important addition to the body of knowledge in this growing field and highlights the need for cost effective genetic screening tools in low resourced settings.

Metastatic Non-Functional Pancreatic Neuroendocrine Tumor in a Patient With a Pathogenic TSC1 Mutation

Abstract Introduction: Tuberous sclerosis complex (TSC) is an autosomal dominant multisystem disorder caused by mutations in two tumor suppressor genes (TSC1 and TSC2) encoding proteins critical in cell growth and proliferation and is associated with an increased risk for benign and malignant tumors. Pancreatic neuroendocrine tumors (PNET) occur in 1.5-1.8% of patients with TSC. They have been primarily reported in TSC2, with only a few cases in the context of TSC1. We describe a non-functional metastatic PNET in a patient with a known pathogenic TSC1 mutation. Case Description: A 49-year old female with a past medical history of bipolar disease, a family history of TSC1 in a daughter, a known pathologic TSC1 mutation (c.2356C&amp;gt;T), and previous history of renal cell carcinoma (RCC) was evaluated for a pancreatic lesion with likely liver metastases. Two years prior to the presentation, a 10 mm pancreatic lesion was initially noted on the CT scan during a renal mass evaluation. Nephrectomy confirmed the RCC. Two years later, surveillance imaging revealed two new lesions in the liver, and the pancreatic lesion had enlarged to 1.3 cm. She denied symptoms suggestive of a functional PNET, and her physical exam was unremarkable. Gallium-68 dotatate (GA-68) PET/CT scan demonstrated avid lesions of both the pancreatic tail and left hepatic lobe. Biopsy of the 3 cm liver mass revealed a metastatic high-grade neuroendocrine carcinoma (mib-1 proliferation index of 15%) favoring a primary PNET. Immunohistochemical stains were positive for chromogranin A, synaptophysin, EMA, PAX 8, CK 20, and villin. Stains for CA 19-9 and CK 7 were negative. Biochemical testing suggested that the PNET was non-functional. Specifically, serum concentrations of gastrin, somatostatin, glucagon, glucose, C-peptide, proinsulin, pancreatic polypeptide, chromogranin A, and vascular endothelial growth factor were within normal limits. The patient underwent distal pancreatectomy and resection of the liver mass. Pathological specimens confirmed the diagnosis of a PNET. The patient remained asymptomatic and was monitored regularly with MRI and GA-68 PET/CT scans without further evidence of the disease for 1.5 years. Conclusions: We conclude that this patient harboring a c.2356C&amp;gt;T TSC1 mutation developed a non-functional metastatic PNET. PNET is a likely component of TSC1.

COVID-19 infection in severe Alpha 1-antitrypsin deficiency: Looking for a rationale

The clinical manifestations of COVID-19 are heterogeneous: 46.4% of patients admitted into hospital reported to have at least one comorbidity. Comorbidities such as COPD, diabetes, hypertension and malignancy predispose patients with Covid-19 to adverse clinical outcomes. Alpha 1-antitrypsin deficiency (AATD) is a genetic disorder caused by pathological mutation(s) in the SERPINA1 gene resulting in an imbalance in proteinase activity which may lead to premature emphysema and COPD.Our aim was to investigate whether people with severe AAT deficiency (AATD) have an increased risk of (severe) COVID-19 infection.We collected data on COVID-19 symptoms, laboratory-confirmed infection, hospitalization and treatment by means of a telephone survey, directly administered to Italian severe AATD subjects in May 2020. We then compared our findings with data collected by the Istituto Superiore di Sanità on the total population in Italy during the same period.We found an higher frequency of SARS-CoV-2 infection in our cohort (3.8%) compared to national data regarding infection, thus giving severe AATD a relative risk of 8. 8 (95%CI 5.1-20,0; p<0.0001) for symptomatic SARS-CoV-2 infection. Moreover, the relative risk (RR) was higher in AATD patients with pre-existing lung diseases (RR 13.9; 95%CI 8.0-33.6; p<0.001), but with a similar death rate (1 in 8, 12.5%) compared to the general population (13.9%; RR 0.9).These preliminary findings highlight the importance of close surveillance in the spread of COVID-19 in patients with severe AATD and underlines the need for further studies into the role of the antiprotease shield in preventing SARS-Cov-2 infection.

Structural bioinformatics survey on disease-inducing missense mutations.

Understanding the molecular mechanisms that correlate pathologies with missense mutations is of critical importance for disease risk estimations and for devising personalized therapies. Thus, we have performed a bioinformatic survey of ClinVar, a database of human genomic variations, to find signals that can account for missense mutation pathogenicity. Arginine resulted as the most frequently replaced amino acid both in benign and pathogenic mutations. By adding the structural dimension to this investigation to increase its resolution, we found that arginine mutations occurring at the protein-DNA interface increase pathogenicity 6.5 times with respect to benign variants. Glycine is the second amino acid among all the pathological missense mutations. Necessarily replaced by larger amino acids, glycine substitutions perturb the structural stability of proteins and, therefore, their functions, being mostly located in buried protein moieties. Arginine and glycine appear as representative of missense mutations causing respective changes in interaction processes and protein structural features, the two main molecular mechanisms of genome-induced pathologies.

Fast computational mutation-response scanning of proteins.

Studying the effect of perturbations on protein structure is a basic approach in protein research. Important problems, such as predicting pathological mutations and understanding patterns of structural evolution, have been addressed by computational simulations that model mutations using forces and predict the resulting deformations. In single mutation-response scanning simulations, a sensitivity matrix is obtained by averaging deformations over point mutations. In double mutation-response scanning simulations, a compensation matrix is obtained by minimizing deformations over pairs of mutations. These very useful simulation-based methods may be too slow to deal with large proteins, protein complexes, or large protein databases. To address this issue, I derived analytical closed formulas to calculate the sensitivity and compensation matrices directly, without simulations. Here, I present these derivations and show that the resulting analytical methods are much faster than their simulation counterparts.

Prevalence of hypophosphatasia in adult patients in rheumatology

HintergrundDie Hypophosphatasie (HPP) ist eine genetische Erkrankung, die durch eine oder mehrere Mutationen im Gen für alkalische Phosphatase (ALP) verursacht wird, verantwortlich für die Kodierung der gewebespezifischen ALP und für den Mineralisierungsprozess.Ziel der ArbeitBestimmung der Prävalenz der HPP bei rheumatologischen Patienten.Material und MethodenRetrospektive Analyse der Krankenakten aller erwachsener Patienten mit pathologisch erniedrigten gesamt ALP-Werten (<35 U/l), die zwischen Januar 2017 und Juni 2019 in der Rheumatologie der Medizinischen Klinik III am Universitätsklinikum Bonn behandelt wurden. Die Analyse wurde in Bezug auf klinische Zeichen sowie auf die Ergebnisse der Gentests für HPP untersucht.ErgebnisseBei 60 von 2289 Patienten (2,62 %) zeigten sich pathologisch niedrige ALP-Werte, bei 30 von ihnen (1,31 %) wurden persistierend niedrige ALP-Werte festgestellt. Bei 19 dieser 30 Patienten wurde ein Gentest für ALP-Genmutationen durchgeführt. Sieben der 19 Patienten (36,84 %) hatten HPP-Zeichen (Insuffizienzfrakturen oder schlechter Zahnstatus seit der Kindheit), alle mit pathologischer ALP-Mutation. Drei dieser Patienten (15,78 %) hatten jeweils eine Insuffizienzfraktur mit normwertiger Knochendichtemessung in der Vorgeschichte. Insgesamt 13 von 19 Patienten wiesen (68,42 %) Mutationen im ALP-Gen auf. Interessanterweise wurde keine Assoziation mit einer Chondrokalzinose festgestellt.DiskussionDie HPP scheint eine unterdiagnostizierte Erkrankung mit einem höheren Anteil betroffener Patienten, welche in der Rheumatologie vorstellig werden, zu sein. Daher sollten zukünftige Studien darauf abzielen, ein Diagnostikprotokoll in der klinischen Praxis zu entwickeln.

A Perspective on Accelerated Aging Caused by the Genetic Deficiency of the Metabolic Protein, OPA1.

Autosomal Dominant Optic Atrophy (ADOA) is an ophthalmological condition associated primarily with mutations in the OPA1 gene. It has variable onset, sometimes juvenile, but in other patients, the disease does not manifest until adult middle age despite the presence of a pathological mutation. Thus, individuals carrying mutations are considered healthy before the onset of clinical symptoms. Our research, nonetheless, indicates that on the cellular level pathology is evident from birth and mutant cells are different from controls. We argue that the adaptation and early recruitment of cytoprotective responses allows normal development and functioning but leads to an exhaustion of cellular reserves, leading to premature cellular aging, especially in neurons and skeletal muscle cells. The appearance of clinical symptoms, thus, indicates the overwhelming of natural cellular defenses and break-down of native protective mechanisms.

Alpha-1 Antitrypsin Screening in a Selected Cohort of Patients Affected by Chronic Pulmonary Diseases in Naples, Italy

Introduction. Alpha-1 antitrypsin deficiency (AATD) is a genetic condition associated with several respiratory diseases in patients with severe protein deficiency. AATD is often late diagnosed or underdiagnosed. Diagnosis frequently occurs in patients with chronic obstructive pulmonary disease and emphysema characterized by frequent exacerbations and over ten years’ duration. The purpose of this study was to evaluate the incidence of alpha-1 antitrypsin deficiency in patients with the chronic pulmonary disease after a thorough screening in the city of Naples in southern Italy. Materials and methods. Two hundred patients suffering from respiratory pathology (chronic obstructive pulmonary disease (COPD), emphysema, asthma, or bronchiectasis) were examined and evaluated in our outpatients’ clinic and tested for serum levels of AAT. Patients who had a respiratory disease suspected of AATD and/or serum AAT < 120 mg/dL underwent genetic testing. Genetic screening was performed on samples from 141 patients. Results. A total of 36 patients had an intermediate deficiency of AAT levels. Among them, 8 were PI*MZ, 6 were PI*MS and 22 had rare pathological mutations. Five patients had a severe AATD, all were composite heterozygous with S or Z allele, while the other allele had a rare pathological mutation. Conclusions. The incidence of genetic defects as AATD in the population of patients affected by chronic respiratory disorders is always a matter of discussion because of the frequent interaction between genes and environmental causes. In our series, numerous rare variants and compound heterozygosity have been described. No homozygous patients have been described. The present is one of few studies available on the incidence of rare variants in the geographic area of the city of Naples. So, our results could be considered interesting not only to know the incidence of AATD and its related rare mutations but also to support early diagnosis and treatments for patients with chronic pulmonary disease and frequent exacerbation and to fight the association with environmental causes of pulmonary damages as smoking.

Molecular Genetic Approach and Evaluation of Cardiovascular Events in Patients with Clinical Familial Hypercholesterolemia Phenotype from Romania.

This study identifies the genetic background of familial hypercholesterolemia (FH) patients in Romania and evaluates the association between mutations and cardiovascular events. We performed a prospective observational study of 61 patients with a clinical diagnosis of FH selected based on Dutch Lipid Clinic Network (DLCN) and Simon Broome score between 2017 and 2020. Two techniques were used to identify mutations: multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing. The mutation rate was 37.7%, i.e., 23 patients with mutations were identified, of which 7 subjects had pathogenic mutations and 16 had polymorphisms. Moreover, 10 variants of the low-density lipoprotein receptor (LDLR) gene were identified in 22 patients, i.e., one variant of the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene in six patients, and one variant of the apolipoprotein B (APOB) gene in three patients. Of the LDLR gene variants, four were LDLR pathogenic mutations (c.81C > G, c.502G > A, c.1618G > A mutations in exon 2, exon 4, exon 11, and exon 13–15 duplication). The PCSK9 and APOB gene variants were benign mutations. The pathogenic LDLR mutations were significant predictors of the new cardiovascular events, and the time interval for new cardiovascular events occurrence was significantly decreased, compared to FH patients without mutations. In total, 12 variants were identified, with four pathogenic variants identified in the LDLR gene, whereas 62.3% of the study population displayed no pathological mutations.

Huntingtin silencing delays onset and slows progression of Huntington's disease: a biomarker study.

Huntington's disease is a dominantly inherited, fatal neurodegenerative disorder caused by a CAG expansion in the huntingtin (HTT) gene, coding for pathological mutant HTT protein (mHTT). Because of its gain-of-function mechanism and monogenic aetiology, strategies to lower HTT are being actively investigated as disease-modifying therapies. Most approaches are currently targeted at the manifest stage, where clinical outcomes are used to evaluate the effectiveness of therapy. However, as almost 50% of striatal volume has been lost at the time of onset of clinical manifest, it would be preferable to begin therapy in the premanifest period. An unmet challenge is how to evaluate therapeutic efficacy before the presence of clinical symptoms as outcome measures. To address this, we aim to develop non-invasive sensitive biomarkers that provide insight into therapeutic efficacy in the premanifest stage of Huntington's disease. In this study, we mapped the temporal trajectories of arteriolar cerebral blood volumes (CBVa) using inflow-based vascular-space-occupancy (iVASO) MRI in the heterozygous zQ175 mice, a full-length mHTT expressing and slowly progressing model with a premanifest period as in human Huntington's disease. Significantly elevated CBVa was evident in premanifest zQ175 mice prior to motor deficits and striatal atrophy, recapitulating altered CBVa in human premanifest Huntington's disease. CRISPR/Cas9-mediated non-allele-specific HTT silencing in striatal neurons restored altered CBVa in premanifest zQ175 mice, delayed onset of striatal atrophy, and slowed the progression of motor phenotype and brain pathology. This study-for the first time-shows that a non-invasive functional MRI measure detects therapeutic efficacy in the premanifest stage and demonstrates long-term benefits of a non-allele-selective HTT silencing treatment introduced in the premanifest Huntington's disease.

Mechanism of misfolding of the human prion protein revealed by a pathological mutation

The misfolding and aggregation of the human prion protein (PrP) is associated with transmissible spongiform encephalopathies (TSEs). Intermediate conformations forming during the conversion of the cellular form of PrP into its pathological scrapie conformation are key drivers of the misfolding process. Here, we analyzed the properties of the C-terminal domain of the human PrP (huPrP) and its T183A variant, which is associated with familial forms of TSEs. We show that the mutation significantly enhances the aggregation propensity of huPrP, such as to uniquely induce amyloid formation under physiological conditions by the sole C-terminal domain of the protein. Using NMR spectroscopy, biophysics, and metadynamics simulations, we identified the structural characteristics of the misfolded intermediate promoting the aggregation of T183A huPrP and the nature of the interactions that prevent this species to be populated in the wild-type protein. In support of these conclusions, POM antibodies targeting the regions that promote PrP misfolding were shown to potently suppress the aggregation of this amyloidogenic mutant.

Evaluation of the international severity score for FMF (ISSF) scores in Turkish children diagnosed with FMF: a single-center experience.

The aim of this study is to evaluate our patients with the newly developed international severity score for FMF (ISSF) and make comparisons with the literature. This cross-sectional study included patients with FMF, were between 6 months and 18 years old, and were using colchicine/colchicine+IL-1 inhibitor for at least 6 months. The patients were classified as mild, intermediate, and severe based on their scores between 1 and 10. In addition to scoring, those who have additional pathological or silent mutation were compared based on these classifications. Our patients consist of 88 women 72 men total 160.The mean age, age of onset, and age of diagnosis were 12 ± 4.3, 4.9 ± 3.7, and 7.5 ± 4 years, respectively, and the mean diagnostic delay was 2.6 ± 3years. When our large patient population is evaluated with ISSF, the disease severity is mostly intermediate. According to ISSF, mild, intermediate, and severe diseases were 21.3%, 70.5%, and 8.1%, respectively. The duration of attacks shorten with increasing age (p > 0.05), and there is an increase in the involvement of other organs during the attacks among patients older than 7 years. ISSF appears as a suitable and effective tool for the physicians in the follow-up of the disease severity in pediatric FMF patients. Key Points • Our article is the first study to evaluate ISSF performance in the pediatric population. • International severity score for FMF (ISSF) appears as a suitable and effective tool for the physicians in the follow-up of the disease severity in pediatric FMF patients. • We think that the addition of pathogenic mutations and inheritance model to the ISSF scoring system as important determinants of disease severity, especially when comparing different patients, can be evaluated in future studies.

Prevalent ALMS1 Pathogenic Variants in Spanish Alström Patients.

Alström syndrome (ALMS) is an ultrarare disease with an estimated prevalence lower than 1 in 1,000,000. It is associated with disease-causing mutations in the Alström syndrome 1 (ALMS1) gene, which codifies for a structural protein of the basal body and centrosomes. The symptomatology involves nystagmus, type 2 diabetes mellitus (T2D), obesity, dilated cardiomyopathy (DCM), neurodegenerative disorders and multiorgan fibrosis. We refined the clinical and genetic diagnosis data of 12 patients from 11 families, all of them from Spain. We also studied the allelic frequency of the different variants present in this cohort and performed a haplotype analysis for the most prevalent allele. The genetic analysis revealed 2 novel homozygous variants located in the exon 8, p.(Glu929Ter) and p.(His1808GlufsTer20) in 2 unrelated patients. These 2 novel variants were classified as pathogenic after an in silico experiment (computer analysis). On the other hand, 2 alleles were detected at a high frequency in our cohort: p.(Tyr1714Ter) (25%) and p.(Ser3872TyrfsTer19) (16.7%). The segregation analysis showed that the pathogenic variant p.(Tyr1714Ter) in 3 families is linked to a rare missense polymorphism, p.(Asn1787Asp). In conclusion, 2 novel pathological mutations have been discovered in homozygosis, as well as a probable founder effect in 3 unrelated families.

Abstract PS11-39: Phase II pilot study of trastuzumab biosimilar (herzuma®) plus gedatolisib in patients with HER-2 positive metastatic breast cancer who progressed after 2 or more HER-2 directed chemotherapy [KM-10A/KCSG18-13 interim analysis

Abstract Background: Prognosis of patients with HER-2 positive metastatic breast cancer (MBC) has been revolutionized with the development of dual antibodies targeting HER-2 and antibody-drug conjugate, but resistance to anti-HER-2 therapy is inevitable ultimately. PI3K-AKT-mTOR pathway aberration is known to be one of the resistance mechanisms. This randomized phase 2 pilot study evaluated safety and efficacy of Herzuma® (trastuzumab biosimilar) plus Gedatolisib (dual PI3K/mTORC inhibitor) in patients with HER-2 positive MBC who progressed after multiple lines of therapy. Methods: Patients with HER-2 positive MBC with known PIK3CA pathologic mutation or amplification whose disease progressed after more than two HER-2 directed therapy were enrolled in the study. They received Herzuma® (8mg/kg IV for 1st cycle loading dose, and then 6mg/kg IV every 3 weeks) plus Gedatolisib (180mg on D1, 8, 15 of every 21 days). We evaluated efficacy of the combination treatment as interim analysis. The data cutoff of this interim analysis was Aug 4, 2020. Results: As a pilot study, 15 patients were enrolled and followed for a median of 2.3 months. At data cutoff, 11 patients were eligible for response assessment. All patients were confirmed to have pathologic PIK3CA aberrations: H1047R, H1047L, E542Q, E542K, E453K, N345K, and PIK3CA amplification. Five patients reached partial response (PR) as their best response, three were stable disease (SD), and three had progressive disease (PD). All patients who have reached PR remain on investigational treatment at the data cutoff point, and the longest one is on treatment for 7.8 months. One of the SD patients ended treatment due to disease progression, and the other two have been undergoing treatment. Overall, response rate was 45.5% and disease control rate was 72.7%. No fatal adverse events related to trial medication were reported. Conclusion: In this phase 2 pilot study, Trastuzumab biosimilar plus Gedatolisib presented 45.5% of response rate with manageable toxicity in patients with HER-2 positive MBC with PIK3CA aberration. Clinical trial information: NCT03698383 Acknowledgement: this research was supported by a grant of the Korea Health Technology R&amp;D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health &amp;Welfare, Republic of Korea (Grant number: HI17C2206). Citation Format: Ju Won Kim, Hee Kyung Ahn, Jong Gwon Choi, Yee Soo Chae, Gyeong Won Lee, Keon Uk Park, Eun Mi Lee, Sung Hoon Sim, Jee Hyun Kim, Yeon Hee Park, Mi So Kim, Jin Hyun Park, Jeong Eun Kim, Han Jo Kim, Mi Sun Ahn, So Yeon Oh, Min Hwan Kim, Su-Jin Koh, Kyoung Eun Lee, Myoung Joo Kang, Jae Ho Byun, Joo young Ha, Jung Hye Kwon, Joo Young Jung, Su Ee Lee, In Hae Park, Kyong Hwa Park. Phase II pilot study of trastuzumab biosimilar (herzuma®) plus gedatolisib in patients with HER-2 positive metastatic breast cancer who progressed after 2 or more HER-2 directed chemotherapy [KM-10A/KCSG18-13 interim analysis] [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS11-39.

Backbone NMR assignments of the C-terminal domain of the human prion protein and its disease\u2010associated T183A variant

Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders associated with the misfolding and aggregation of the human prion protein (huPrP). Despite efforts into investigating the process of huPrP aggregation, the mechanisms triggering its misfolding remain elusive. A number of TSE-associated mutations of huPrP have been identified, but their role at the onset and progression of prion diseases is unclear. Here we report the NMR assignments of the C-terminal globular domain of the wild type huPrP and the pathological mutant T183A. The differences in chemical shifts between the two variants reveal conformational alterations in some structural elements of the mutant, whereas the analyses of secondary shifts and random coil index provide indications on the putative mechanisms of misfolding of T183A huPrP.