Asparagine Linked Glycosylation Protein 9 (ALG9)

All 6 affected individuals were carriers of a balanced chromosomal translocation, t(9;11)(p24;q23). By gene analysis of the breakpoint junctions, Baysal et al. (2002) identified disruption of a novel gene at 11q23, which they symbolized DIBD1.

The predicted 611-amino acid DIBD1 protein is a mannosyltransferase similar to the S. cerevisiae Alg9 protein of the N-glycosylation pathway and has 8 transmembrane helices. Northern blot analysis detected expression of DIBD1 in all tissues tested, with highest expression in heart, liver, and pancreas. The most abundant transcript was 2.5 kb, although 0.25-, 5.5-, and 7.0-kb transcripts were also observed. In subregions of the brain, the 2.5- and 7.0-kb transcripts were expressed ubiquitously.