Alpha-dystroglycanopathy (FCMD, MEB, etc): abnormal glycosylation and muscular dystrophy

Fukuyama congenital muscular dystrophy (FCMD), Walker-Warburg syndrome (WWS), and muscle-eye-brain (MEB) disease are similar disorders characterized by congenital muscular dystrophy, brain and eye anomalies. We previously identified the genes for FCMD and MEB, which encode fukutin and POMGnT1. Recent studies have revealed that posttranslational modification of alpha-dystroglycan is associated with congenital muscular dystrophy with brain malformations. Since hypoglycosylation of alpha-dystroglycan is common amongst several other disorders, a new clinical entity called alpha-dystroglycanopathy is proposed. However, only POMGnT1 (MEB) and POMT1 (WWS) are shown to have a definite enzymatic activity, and no enzymatic activity has been detected in fukutin. We show positive interactions between fukutin and POMGnT1. Fukutin may form a protein complex with POMGnT1 and modulate POMGnT1's enzymatic activity. Through cDNA microarray, we also show aberrant neuromuscular junction formation and delayed muscle fiber maturation in alpha-dystroglycanopathies, suggesting a new pathomechanism.