Maternal uniparental disomy for chromosome 14 with diabetes mellitus.

A 20-year-old Japanese man was admitted to our hospital because of thirst and weight loss. His fasting plasma glucose, glycated hemoglobin, and urinary C-peptide were 262 mg/dl, 13.6%, and 44.8 microg/day, respectively, and the autoimmune antibodies related to type 1 diabetes were negative. Chromosome analysis of his peripheral blood lymphocytes showed a mos45,XY,der(14;14)(q10;ql0)[129]/ 46,XY,+14, der(14;14)(q10;q10)[1] karyotype. His parents were karyotypically normal. Microsatellite marker analysis on chromosome 14 demonstrated mosaic maternal segmental isodisomy for 14q21-q24. Although the parents had normal glucose regulation, the patient who finally returned to impaired glucose tolerance and his mother both have a deficiency in early postprandial insulin secretion. Since obesity was mild (body mass index, 24.1 kg/m2) and he was relatively young for type 2 diabetes, we speculated that his isodisomy 14 may have been involved in the onset of diabetes mellitus in this patient.