Phenotypic variability associated with Arg26Gln mutation in caveolin3

Caveolin3 (CAV3) is a protein associated with dystrophin, dystrophin-associated glycoproteins, and dysferlin. Mutations in the CAV3 gene result in certain autosomal-dominant inherited diseases, namely, rippling muscle disease (RMD), limb-girdle muscular dystrophy type 1C (LGMD1C), distal myopathy, and hyperCKemia. In this report we show that a previously reported family with RMD has a mutation in the CAV3 gene. Affected individuals had either a characteristic RMD phenotype, a combination of RMD and LGMD1C phenotypes, or a LGMD1C phenotype, but one mutation carrier was asymptomatic at age 86 years. This phenotypic variability associated with mutations in CAV3 has been reported previously but only in a few families. It is important to remember the significant phenotypic variability associated with CAV3 mutations when counseling families with these mutations. These observations also suggest the presence of factors independent of the CAV3 gene locus that modify phenotype.