Multiple Functions of Fukutin, the Gene Responsible for Fukuyama Congenital Muscular Dystrophy, Especially in the Central Nervous System

Fukuyama congenital muscular dystrophy (FCMD), accompanying central nervous system (CNS) and ocular anomalies, is the second common muscular dystrophy in Japan, and the responsible gene is fukutin. The lesions are mainly caused by fragile basement membrane/cell membrane due to hypoglycosylation of α-dystroglycan (α-DG), and astrocytes play a crucial role for CNS malformation. On the other hand, since fukutin is expressed almost ubiquitously, diverse functions of fukutin, besides the glycosylation of α-DG, can be considered. As for the CNS, fukutin possibly upregulates cyclin D1 expression as a cofactor of activator protein-1 in astrocytoma. Moreover, fukutin may be involved in the phosphorylation of tau, one of the key proteins of dementia represented by Alzheimer’s disease, in glutamatergic neurons. A presynaptic function in GABAergic neurons is also suggested. Owing to the recent advances of molecular and biochemical techniques, new therapeutic strategies are under consideration, even for brain malformation, which begins to be formed during the first trimester in utero. Recovery of hypoglycosylation of α-DG supposed to be a main therapeutic target, but to know various functions and regulation systems of fukutin might be important for developing suitable therapies.