👤 Navid A Nafissi

Atrial fibrillation (AF) is a prevalent and morbid abnormality of the heart rhythm with a strong genetic component. Here, we meta-analyzed genome and exome sequencing data from 36 studies that included 52,416 AF cases and 277,762 controls. In burden tests of rare coding variation, we identified novel associations between AF and the genes MYBPC3, LMNA, PKP2, FAM189A2 and KDM5B. We further identified associations between AF and rare structural variants owing to deletions in CTNNA3 and duplications of GATA4. We broadly replicated our findings in independent samples from MyCode, deCODE and UK Biobank. Finally, we found that CRISPR knockout of KDM5B in stem-cell-derived atrial cardiomyocytes led to a shortening of the action potential duration and widespread transcriptomic dysregulation of genes relevant to atrial homeostasis and conduction. Our results highlight the contribution of rare coding and structural variants to AF, including genetic links between AF and cardiomyopathies, and expand our understanding of the rare variant architecture for this common arrhythmia. Show less

To broaden our understanding of bradyarrhythmias and conduction disease, we performed common variant genome-wide association analyses in up to 1.3 million individuals and rare variant burden testing in 460,000 individuals for sinus node dysfunction (SND), distal conduction disease (DCD) and pacemaker (PM) implantation. We identified 13, 31 and 21 common variant loci for SND, DCD and PM, respectively. Four well-known loci (SCN5A/SCN10A, CCDC141, TBX20 and CAMK2D) were shared for SND and DCD, while others were more specific for SND or DCD. SND and DCD showed a moderate genetic correlation (r Show less

Congenital myasthenic syndromes (CMSs) are genetic disorders affecting motor function with variable symptoms. RAPSN-related CMS, caused by mutations in the RAPSN gene, leads to muscle weakness. Accurate diagnosis is essential for proper management. This study aims to analyze six Iranian families affected by RAPSN-CMS, focusing on clinical manifestations, genetic variants, treatment response, and outcomes. Clinical assessments, genetic analysis, and whole-exome sequencing were performed on the six families to identify RAPSN gene mutations. The study examined symptoms, disease severity, age of onset, treatment response, and outcomes. Treatment with pyridostigmine and salbutamol was given to assess its effectiveness. Three homozygous known variants in RAPSN gene were identified: c.491G > A in three families, c.264 C > A in two families, and c.-210 A > G in one family. Clinical assessments showed diversity in symptoms and treatment responses. Pyridostigmine and salbutamol treatment improved symptoms and quality of life. This study highlights the significance of molecular diagnosis for RAPSN-related congenital myasthenic syndromes (CMS) in Iran, marking the first comprehensive genetic analysis in the region. The identification of specific pathogenic variants underscores the unique genetic landscape of local patients. Furthermore, our long-term follow-up revealed variable treatment responses, emphasizing the need for personalized care strategies. The clinical variability among patients with identical mutations necessitates a multidisciplinary approach for effective management. By enhancing genetic awareness and refining follow-up methods, we aim to improve diagnosis accuracy and interventions, fostering better outcomes for affected families in the Iranian population. Show less

Inherited primary arrhythmia syndromes and arrhythmogenic cardiomyopathies can lead to sudden cardiac arrest in otherwise healthy individuals. The burden and expression of these diseases in a real-world, well-phenotyped cardiovascular population is not well understood. Whole exome sequencing was performed on 8574 individuals from the CATHGEN cohort (Catheterization Genetics). Variants in 55 arrhythmia-related genes (associated with 8 disorders) were identified and assessed for pathogenicity based on American College of Genetics and Genomics/Association for Molecular Pathology criteria. Individuals carrying pathogenic/likely pathogenic (P/LP) variants were grouped by arrhythmogenic disorder and matched 1:5 to noncarrier controls based on age, sex, and genetic ancestry. Long-term phenotypic data were annotated through deep electronic health record review. Fifty-eight P/LP variants were found in 79 individuals in 12 genes associated with 5 arrhythmogenic disorders (arrhythmogenic right ventricular cardiomyopathy, Brugada syndrome, hypertrophic cardiomyopathy, In a real-world cardiovascular cohort, P/LP variants in arrhythmia-related genes were relatively common (1:108 prevalence) and most penetrant in Show less

Gene expression profiling has been suggested to predict breast cancer outcome. The prognostic value of the 8q22-24 position in breast cancer remains to be elucidated. The present study evaluated expression patterns of the genes located at this position in metastatic and non-metastatic breast cancer. A total of 85 patients with recurrent/metastatic (n=15) and non-metastatic (n=70) early-stage, estrogen receptor-positive and lymph node-negative breast tumors were included. In addition, 15 normal breast tissue samples were used as controls. Demographic and clinical features were recorded. Subsequently, mRNA copy numbers of exostosin glycosyltransferase 1 ( Show less