Exonic deletions in the MAL gene, encoding Myelin and Lymphocyte protein, define the rare inherited AnWj-negative phenotype: Exonic deletions in the MAL gene, encoding Myelin and Lymphocyte protein, define the rare inherited AnWj-negative phenotype

Background: AnWj (ISBT 901009) is a high prevalence blood group antigen present on red cells and epithelial tissues of more than 99.9% of individuals but absent on cord cells. Antibodies directed to AnWj antigen are rare and are usually associated with transient suppression of AnWj expression, although a small number of individuals have a persistent, autosomal recessive inherited AnWj-negative phenotype. Anti-AnWj may be clinically significant and has been associated with acute hemolytic transfusion reactions.
The carrier molecule for the AnWj antigen has remained elusive; although CD44 and Smyd1 histone methyltransferase have both been reported to be associated with AnWj expression, the mechanism for this has not been elucidated.
Myelin and lymphocyte protein (Mal), encoded by the MAL gene on chromosome 2, is an integral 17KDa multi-pass membrane proteolipid, expressed on T-lymphocytes, myelin-forming cells and polarised epithelial cells. It has also been identified as the receptor for Clostridium perfringens epsilon toxin on erythrocyte membranes.