Cloning, characterization, and chromosome mapping of the human GlcAT-S gene.

We report on the structure, map location, and tissue expression of the human GlcAT-Sgene. The gene covers approximately 85 Kb on chromosome 6 (6q13) between the D6S455 and D6S1673 markers. GlcAT-S is composed of four exons and encodes a 324-amino-acid protein, which shows 89% homology with the rat glcat-s protein and is involved in the biosynthesis of the HNK-1 carbohydrate epitope on glycoproteins. Although GlcAT-Swas considered an interesting candidate gene for the RP25 locus, the absence of any pathogenic mutations in probands of RP25-linked families ruled out that candidacy.