A detailed investigation of maternally inherited diabetes and deafness (MIDD) including clinical characteristics, C-peptide secretion, HLA-DR and -DQ status and autoantibody pattern.

A missing first phase and a decreased total C-peptide response during an IVGTT was characteristic for the A3243G mutation. The fasting C-peptide level of the carriers did not differ from the controls. Circulating ICA was present in some patients, but GAD, IA-2 and mitochondrial antibodies were absent. All subjects had HLA-DR1-DQ5 haplotype, and either -DQ5 or -DQ6 alleles.