Congenital Disorder of Glycosylation-Ic: Case Report and Genetic Defect

The clinical phenotype and the molecular defect of a patient with a new subtype of congenital disorders of glycosylation (CDG-Ic, formerly designated as CDGS type V) characterized by a deficiency of Dol-P-Glc : Man₉GlcNAc₂-PP-Dol glucosyltransferase is described. The clinical picture presents with several features similar to CDG-Ia (phosphomannomutase 2 deficiency) such as hypotonia and atactic-dystonic movements. In contrast to CDG-Ia, the course of the disease appears milder. The head growth, the functioning of the peripheral nerves and the initial cerebellar development were normal. Sequencing of the patient's Dol-P-Glc : Man₉GlcNAc₂-PP-Dol glucosyltransferase cDNA revealed an in-frame deletion of three nucleotides leading to the loss of isoleucine 299.

CDG - Dol-P-Glc : Man₉ - GlcNAc₂ - -PP-Dol glucosyltransferase

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