Klaus-H. Usadel

CYP27B1 polymorphisms variants are associated with type 1 diabetes mellitus in Germans.

CYP27B1 (25-hydroxyvitamin D(3)-1alpha-hydroxylase) catalyzes the metabolization of 25-hydroxyvitamin D(3) to 1,25(OH)(2)D(3) the most active natural Vitamin D metabolite. 1,25(OH)(2)D(3) plays a role in the regulation of autoimmunity and cell proliferation and prevents the development of autoimmune diabetes mellitus in animal models besides other autoimmune disorders. One hundred and eighty-seven families with one offspring affected with type1diabetes mellitus were genotyped for the polymorphisms in the promoter region (-1260 C/A) and intron 6 (2338 T/C) of the CYP27B1 gene on chromosome 12 q13.1-13.3 and extended transmission disequilibrium tests (ETDT) were performed. The haplotype CT (-1260 A/2338 T) was significantly more often transmitted to affected offspring (96 transmitted (T) versus 63 not transmitted (NT), P = 0.0089). While the AT (-1260 C/2838 T) was significantly less often transmitted (37 T versus 60 NT, P = 0.0195). This study suggests that CYP27B1 haplotypes may confer susceptibility to type 1 diabetes mellitus in Germans.

Preliminary evidence that an endogenous retroviral long‐terminal repeat (LTR13) at the HLA‐DQB1 gene locus confers susceptibility to Addison's disease

OBJECTIVE Addisons disease is associated with particular haplotypes of the human leucocyte antigen (HLA) region [DQA1*0501‐DQB1*0201 (DQ2) and DQA1*0301‐DQB1*0302 (DQ8)]. This locus harbours several human endogenous retroviral (HERV) long‐terminal repeats (LTR). LTRs within the HLA region have been shown to confer additional susceptibility to type 1 diabetes and rheumatoid arthritis.