Unusual association of insulin-dependent diabetes mellitus with congenital myasthenia gravis and autoimmune thyroid disease.

A 26-year-old woman with congenital myasthenia gravis and antibodies to the acetylcholine receptor developed overt insulin-dependent diabetes with positive islet cell antibodies and thyroid microsomal and gastric parietal cell antibodies. Her younger sister has been an insulin-dependent diabetic since the age of 7 years, and the mother has nongoitrous hypothyroidism. In the same period the woman in question developed a transient chemical hyperthyroidism. HLA typing of the family members showed that the diabetes was probably associated with an HLA AW30, BW38, DR4 haplotype, found in both sisters and in their father, and that the thyroid disease was associated with the A29, B7, DR6 haplotype found in the patient and in her mother. This familial HLA pattern may indicate that each autoimmune manifestation in the patient is due to a different susceptible gene associated with the HLA system.