Congenital disorders of glycosylation. Part II. Defects of protein O-glycosylation.
Glycosylation is a form of post-translational modification of proteins and occurs in every living cell. The carbohydrate chains attached to the proteins serve various functions. There are two main types of protein glycosylation: N-glycosylation and O-glycosylation. In this paper, we describe the O-glycosylation process and currently known congenital disorders of glycosylation associated with defects of protein O-glycosylation. This process takes place in the cis Golgi apparatus after N-glycosylation and folding of the proteins. The O-glycosylation is essential in the biosynthesis of mucins, the formation of proteoglycan core proteins and blood group proteins. Most common forms of O-glycans are the mucin-type glycans. There are more than 20 known disorders related to O-glycosylation disturbances. We review 8 of the following diseases linked to defects in the synthesis of O-xylosylglycans, O-N acetylgalactosaminylglycans, O-xylosyl/N-acetylglycans, O-mannosylglycans, and O-fucosylglycans: multiple exostoses, progeroid variant of Ehlers-Danlos syndrome, progeria, familial tumoral calcinosis, Schneckenbecken dysplasia, Walker-Warburg syndrome, spondylocostal dysostosis type 3, and Peter's plus syndrome. Causes of these diseases include gene mutations and deficiency of proteins (enzymes). Their diagnosis includes syndromic presentation, organ-specific expression and laboratory findings.
Department of Biochemical Diagnostics, Medical University of Bialystok, Białystok, Poland.
Bogdan
B
Cylwik
Karina
K
Lipartowska
Lech
L
Chrostek
Ewa
E
Gruszewska
D001789:Blood Group Antigens / Q000235:genetics / Q000378:metabolism*; D002240:Carbohydrate Sequence; D018981:Congenital Disorders of Glycosylation / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation; D005936:Glucans / Q000737:chemistry / Q000378:metabolism; D006031:Glycosylation; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008351:Mannans / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009077:Mucins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D017510:Protein Folding; D014990:Xylans / Q000737:chemistry / Q000378:metabolism
D001789:Blood Group Antigens; D005936:Glucans; D008351:Mannans; D009077:Mucins; D014990:Xylans