HLA-DRB1 and DQB1 genotypes in patients with insulin-dependent neonatal diabetes mellitus. A study of 13 cases

Insulin-dependent neonatal diabetes mellitus (NDM) is a rare form of diabet es with a heterogeneous genetic background. The HLA-DRB1 and DQB1 genotypes were determined for 13 patients with NDM, from 9 unrelated families. Four patients had permanent NDM (PNDM) and 9 patients had transient NDM (TNDM. N o excess of HLA susceptibility markers for type 1 diabetes (IDDM) was obser ved in this series of patients, whatever the forms of diabetes PNDM or TNDM . Paternal isodisomy of chromosome 6 was observed in two TNDM cases. These observations are consistent with thr current hypothesis that there is a rec essive susceptibility gene, at least in the transient form of the disease, unlinked to the MHC locus on chromosome 6. Although established in a short series, our results do not support an additive role of IDDM1 in the progres sion of the disease.