Leukocyte adhesion deficiency (LAD) type II/carbohydrate deficient glycoprotein (CDG) IIc founder effect and genotype/phenotype correlation.

Leukocyte adhesion deficiency (LAD) type II is a rare autosomal recessive syndrome characterized by recurrent infections, typical dysmorphic features, the Bombay blood phenotype and severe growth and psychomotor retardation. It is attributed to a general absence of fucosylated glycans on the cell surface. Three Arab Israeli patients and one Turkish child have been reported so far. The primary defect in a specific GDP-L-fucose transporter of the Golgi apparatus has been disclosed recently. All three children reported by us are homozygous for one single founder mutation, different from that reported in the Turkish child. The amount of mRNA of the GDP-L-fucose transporter in cells from Arab patients and their parents are comparable to controls. Genotype/phenotype correlation studies show that the two different mutations are distinguished by differences in response to fucose supplementation and in the clinical phenotypes.