May be a glycosyltransferase which participates in glycosylation of alpha-dystroglycan/DAG1. May interact with and reinforce a large complex encompassing the outside and inside of muscle membranes. Could be involved in brain development.
Widely expressed with highest expression in brain, heart, pancreas and skeletal muscle. Expressed at similar levels in control fetal and adult brain, but is much reduced in Fukuyama-type congenital dystrophy (FCMD) brains. Expressed in migrating neurons, including Cajar-Retzius cells and adult cortical neurons, as well as hippocampal pyramidal cells and cerebellar Purkinje cells. No expression observed in the glia limitans, the subpial astrocytes (which contribute to basement membrane formation) or other glial cells. In the FCMD brain, neurons in regions with no dysplasia show fair expression, whereas transcripts are nearly undetectable in the overmigrated dysplastic region.
Involvement in disease
Defects in FKTN are the cause of muscular dystrophy-dystroglycanopathy congenital with brain and eye anomalies type A4 (MDDGA4) [MIM:253800]; also called congenital muscular dystrophy Fukuyama type (FCMD) or Walker-Warburg syndrome FKTN-related. MDDGA4 is an autosomal recessive disorder characterized by congenital muscular dystrophy associated with cobblestone lissencephaly and other brain anomalies. Patients suffer from generalized skeletal muscle weakness and hypotonia from early infancy, mental retardation and seizures. Occasional features include optic atrophy, retinal detachment, cardiomyopathy. Defects in FKTN are the cause of muscular dystrophy-dystroglycanopathy congenital without mental retardation type B4 (MDDGB4) [MIM:613152]. An autosomal recessive disorder characterized by congenital muscular dystrophy and evidence of dystroglycanopathy. Features included increased serum creatine kinase, generalized weakness, mild white matter changes on brain MRI in some cases, and absence of mental retardation. Defects in FKTN are the cause of muscular dystrophy-dystroglycanopathy limb-girdle type C4 (MDDGC4) [MIM:611588]. MDDGC4 is an autosomal recessive degenerative myopathy characterized by progressive weakness of the pelvic and shoulder girdle muscles and elevated serum creatine kinase. The severity of the disease depends on age at onset which may vary from early to late childhood or even adulthood. MDDGC4 is a novel form of LGMD2 and has no brain involvement and a remarkable clinical response to corticosteroids. Defects in FKTN are the cause of cardiomyopathy dilated type 1X (CMD1X) [MIM:611615]; also called dilated cardiomyopathy with mild or no proximal muscle weakness. Dilated cardiomyopathy is a disorder characterized by ventricular dilation and impaired systolic function, resulting in congestive heart failure and arrhythmia. Patients are at risk of premature death.