Fukuyama-type congenital muscular dystrophy and defective glycosylation of α-dystroglycan

Fukuyama-type congenital muscular dystrophy (FCMD) is a severe form of muscular dystrophy accompanied by abnormalities in the eye and brain. The incidence of FCMD is particularly high in the Japanese population. Mutations in the fukutin gene have been identified in patients with FCMD. Fukutin is predicted to be a Golgi apparatus resident protein and to be involved in the post-translational modification of cell-surface proteins. Recently, progress has been made in our understanding of the molecular mechanisms by which the mutation of fukutin leads to the phenotype of FCMD. Loss of function of fukutin results in defective glycosylation of α-dystroglycan, a central component of the dystrophin-glycoprotein complex, leading to disruption of the linkage between basal lamina and cytoskeleton. This disruption is implicated in the pathogenesis of both the MD and brain anomalies in FCMD. Furthermore, genetic analyses have revealed that the spectrum of the FCMD phenotype is much wider than originally thought. In this review, we summarize the diverging clinical phenotype of FCMD and its molecular pathomechanisms.