Type 1 diabetes with positive anti-GAD antibodies was diagnosed in 6% (1/18), 11% (2/18) had DAT-positive autoimmune hemolytic anemia (AIHA), 6% (1/18) had seronegative rheumatoid arthritis, and 6% (1/18) had primary hyperparathyroidism. This evidence concerns the gene GAD1 and primary hyperparathyroidism.