Polymorphism analysis of Fukuyama type congenital muscular dystrophy (FCMD) siblings with different phenotypes

Peak motor function in Fukuyama type congenital muscular dystrophy (FCMD) is generally considered to be no better than sitting without help or sliding on the buttocks. There are a few patients who acquire the ability to stand and a small fraction of our total congenital muscular dystrophy (CMD) population are able to walk at some point. These ambulant cases may reflect a broad spectrum of motor disabilities in the category of FCMD, or may represent another CMD entity, which closely resembles but is distinct from FCMD. Since the localization of the FCMD gene to chromosome 9q3 1 by Toda et al. in 1993 and 1994, polymorphism analysis of this disease has become possible. We describe correlations between clinical features and genetic analysis using microsatellite markers flanking the FCMD locus in two FCMD families each having two affected children with distinctly different motor abilities. The results demonstrate that two sets of FCMD siblings share exactly the same haplotype at nine marker loci spanning 23.3 cM, surrounding the FCMD locus. Our results provide genetic confirmation that some FCMD cases may acquire the ability to walk.