Arrhythmogenic right ventricular cardiomyopathy type 6 (ARVC6): support for the locus assignment, narrowing of the critical region and mutation screening of three candidate genes.
BACKGROUND
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable disorder characterized by progressive degeneration of right ventricular myocardium, arrhythmias and an increased risk of sudden death at a young age. By linkage analysis, ARVC type 6 was previously mapped to a 10.6 cM region on chromosome 10p12-p14 in a large North American kindred. To date, the genetic defect that causes ARVC6 has not been identified.


METHODS
We identified a South African family of 13 members with ARVC segregating as an autosomal dominant disorder. The diagnosis of ARVC was based on international diagnostic criteria. All available family members were genotyped with microsatellite markers at six known ARVC loci, and positional candidate gene screening was performed.


RESULTS
Genetic linkage and haplotype analysis provided lod scores that are highly suggestive of linkage to the ARVC6 locus on chromosome 10p12-p14, and the narrowing of the critical region to approximately 2.9 Mb. Two positional candidate genes (ITG8 and FRMD4A) were screened in which defects could possibly disrupt cell-cell adhesion. A non-positional candidate gene with apoptosis inducing properties, LAMR1P6 (laminin receptor 1 pseudogene 6) was also screened. Direct sequencing of DNA from affected individuals failed to detect disease-causing mutations in the exonic sequences of the three genes investigated.


CONCLUSIONS
The narrowing of the ARVC6 critical region may facilitate progress towards the identification of the gene that is involved in ARVC. Identification of the causative genes for ARVC will contribute to the understanding of the pathogenesis and management of this poorly understood condition.
The Cardiac Clinic, Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa. matolwenil2@students.wits.ac.za
Luzuko O
LO
Matolweni
Soraya
S
Bardien
George
G
Rebello
Ekow
E
Oppon
Miroslav
M
Munclinger
Rajkumar
R
Ramesar
Hugh
H
Watkins
Bongani M
BM
Mayosi
D000293:Adolescent; D000328:Adult; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000175:diagnosis / Q000235:genetics*; D002879:Chromosomes, Human, Pair 10; D019295:Computational Biology; D004252:DNA Mutational Analysis; D005260:Female; D008040:Genetic Linkage; D020022:Genetic Predisposition to Disease; D006801:Humans; D039001:Integrin alpha Chains / Q000235:genetics; D008297:Male; D008840:Microfilament Proteins / Q000235:genetics; D010375:Pedigree; D011544:Pseudogenes; D012269:Ribosomal Proteins / Q000235:genetics
D039001:Integrin alpha Chains; D008840:Microfilament Proteins; D012269:Ribosomal Proteins