Rare leukocyte adhesion deficiency type II (LAD II) is due to an inborn error in fucose metabolism caused by mutations in the guanosine diphosphate-fucose transporter gene. There is a failure to express the ligand for E and P selectin, sialyl Lewis-X (CD15s), which is expressed on leukocytes. The patients are unable to fucosylate other glycoproteins, including the H blood group polysaccharide, so they are Bombay phenotype, ie, negative for the O and H blood group antigens and capable of making anti-H antibody. The immunoglobulin M (IgM) and immunoglobulin G (IgG) heavy chains also are not fucosylated, although IgM and IgG are present in normal amounts.
Alternative names
LAD2
Congenital disorder of glycosylation type IIc (CDG-IIc)
Leukocyte adhesion deficiency type 2, GDP-fucose transporter
Rambam-Hasharon syndrome; RHS
Classification
- Defects of phagocyte function
- Leukocyte adhesion defects
Inheritance
Autosomal recessive