Subjects: Cases are two patients with type 1 diabetes mellitus (T1DM), with the characteristic relationship and onset situation. Case 1 is 46-year-old daughter and case 2 is 69-year-old mother. They have been living apart and they rarely meet together. Twenty-two months after the onset of T1DM case 1, case 2 also developed T1DM. They did not notice clinical manifestation of upper respiratory infection, or they did not have any stressful matters before the onset of T1DM.
Results: Their data in case 1 vs 2 were as follows: BMI 21.3 vs 19.8, HbA1c 10.3% vs 9.8%, anti-IA-2 antibody (IA-2 Ab) 2.1 vs 6.0 (<0.4), anti-GAD antibody (GAD Ab) 24 vs 10000 (<1.5), HLA-DR type DR9 / DR13 vs DR4/DR13.
Discussion and conclusion: These 2 cases have characteristic mode for the onset of T1DM. In Japanese race, DR4 and DR9 have rather high sensitivity for T1DM, DR15 (DR2) has resistance for T1DM and DR13 has unremarkable influence. From these, HLA-DR type would be possible involved in the onset of T1DM, and further investigation would be expected