Localization of a gene responsible for arrhythmogenic right ventricular dysplasia to chromosome 3p23

Background-Arrhythmogenic right ventricular dysplasia (ARVD), a familial ca rdiomyopathy occurring with a prevalence of 1 in 5000, is characterized by replacement of myocytes with fatty and fibrous tissue. Clinical manifestati ons include structural and functional abnormalities of the right ventricle and arrhythmias, leading to a sudden death rate of 2.5% per year. Four loci have been mapped, but no gene has been identified as yet. Methods and Results-We identified a large family of >200 members with ARVD segregating as an autosomal dominant trait affecting 10 living individuals. The diagnosis of ARVD was based on international diagnostic criteria inclu ding history, physical examination, EGG, echocardiogram, right ventricular angiogram, endomyocardial biopsy, and 24-hour ambulatory EGG. Blood was col lected for DNA from 149 family members. Analysis of 257 polymorphic microsa tellite markers by genetic linkage excluded previously known loci for ARVD and identified a novel locus at 3p23. Analysis of an additional 20 markers further defined the region. A peak logarithm of the odds score of 6.91 was obtained with marker D3S3613 at theta=0% recombination. Haplotype analysis identified a shared region between markers D3S3610 and D3S3659 of 9.3 cM. Conclusions-A novel locus for ARVD has been mapped to 3p23 and the region n arrowed to 9.3 cM. Identification of the gene will allow genetic screening and a specific diagnosis for a disease with protean nonspecific findings. I t should also provide insight fundamental to understanding cardiac chamber- specific gene expression and/or the mechanism of myocyte apoptosis observed in this disease.