FKTN

The protein encoded by this gene is a putative transmembrane protein that is localized to the cis-Golgi compartment, where it may be involved in the glycosylation of alpha-dystroglycan in skeletal muscle. The encoded protein is thought to be a glycosyltransferase and could play a role in brain development. Defects in this gene are a cause of Fukuyama-type congenital muscular dystrophy (FCMD), Walker-Warburg syndrome (WWS), limb-girdle muscular dystrophy type 2M (LGMD2M), and dilated cardiomyopathy type 1X (CMD1X). Alternatively spliced transcript variants have been found for this gene.

FKTN

Catalyzes the transfer of CDP-ribitol to the distal N-acetylgalactosamine of the phosphorylated O-mannosyl trisaccharide (N-acetylgalactosamine-beta-3-N-acetylglucosamine-beta-4-(phosphate-6-)mannose), a carbohydrate structure present in alpha-dystroglycan (DAG1) (PubMed:17034757, PubMed:25279699, PubMed:26923585, PubMed:29477842).

This constitutes the first step in the formation of the ribitol 5-phosphate tandem repeat which links the phosphorylated O-mannosyl trisaccharide to the ligand binding moiety composed of repeats of 3-xylosyl-alpha-1,3-glucuronic acid-beta-1 (PubMed:17034757, PubMed:25279699, PubMed:26923585, PubMed:29477842).

Required for normal location of POMGNT1 in Golgi membranes, and for normal POMGNT1 activity (PubMed:17034757).

May interact with and reinforce a large complex encompassing the outside and inside of muscle membranes (PubMed:25279699).

Could be involved in brain development (Probable).

Muscle organ development Source: ProtInc
Negative regulation of cell population proliferation Source: BHF-UCL
Negative regulation of JNK cascade Source: BHF-UCL
Nervous system development Source: ProtInc
Protein O-linked glycosylation Source: UniProtKB
Protein O-linked mannosylation Source: UniProtKB
Regulation of protein glycosylation Source: BHF-UCL

Golgi apparatus membrane; Nucleus; Cytoplasm. In retinal tissue, does not localize with the Golgi apparatus.

Muscular dystrophy-dystroglycanopathy congenital with brain and eye anomalies A4 (MDDGA4):
An autosomal recessive disorder characterized by congenital muscular dystrophy associated with cobblestone lissencephaly and other brain anomalies, eye malformations, profound mental retardation, and death usually in the first years of life. Included diseases are the more severe Walker-Warburg syndrome and the slightly less severe muscle-eye-brain disease.
Muscular dystrophy-dystroglycanopathy congenital without mental retardation B4 (MDDGB4):
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, and absence of mental retardation.
Muscular dystrophy-dystroglycanopathy limb-girdle C4 (MDDGC4):
An autosomal recessive degenerative myopathy characterized by progressive weakness of the pelvic and shoulder girdle muscles, and elevated serum creatine kinase. MDDGC4 has no brain involvement and a remarkable clinical response to corticosteroids.
Cardiomyopathy, dilated 1X (CMD1X):
A disorder characterized by ventricular dilation and impaired systolic function, resulting in congestive heart failure and arrhythmia. Patients are at risk of premature death.

Cytoplasmic: 1-7
Helical: 8-28
Lumenal: 29-461