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 (CDC-lc, formerly designated as CDGS type V) characterized by a deficiency of Dol-P-Glc:Man(9)GlcNAc(2)-PP-Dol glucosyltransferase is described. The clinical picture presents with several features similar to CDC-la (phosphomannomutase 2 deficiency) such as hypotonia and atactic-dystonic movements. In contrast to CDG-1a, 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-Clc:Man(9)GlcNAc(2)-PP-Dol glucosyltransferase cDNA revealed an in-frame deletion of three nucleotides leading to the loss of isoleucine 299.