Abstract
A seventeen-year-old girl with insulin dependent diabetes mellitus (IDDM) had also selective IgA deficiency and No.9 chromosome aberration. The onset of IDDM was at the age of seven, and it happened that selective IgA deficiency and No.9 chromosome aberration were found out at the age of nine and twelve respectively.
Secretory IgA level in the serum and saliva was reduced because of selective lgA deficiency, however she had rarely suffered from infectious diseases. In addition, she had no IgG subclass deficiency. According to the study of immunoglobulin synthesis of lymphocytes in vitro, the impediment of maturity of B lymphocytes producing IgA was suspected as one of the causes of selective IgA deficiency in this case.
This case had No.9 chromosome aberration, and the karyotype was 46, XX, inv (9p+q-) both in G-band stain and C-band stain. Mother of this case had the same abnormality in No.9 chromosome.
This case had HLA-Cw 1 and Bw 54 which were frequently observed in Japanese IDDM patients, but did not have HLA-B 8 which was frequently observed in Caucasian IDDM patients with selective IgA deficiency.
