Alstrom syndrome (ALMS) is caused by homozygous or compound heterozygous mutation in the ALMS1 gene on chromosome 2p13. This disorder is characterized by progressive cone–rod dystrophy leading to blindness, sensorineural hearing loss, childhood obesity associated with hyperinsulinemia, and type 2 diabetes mellitus. Dilated cardiomyopathy occurs in approximately 70% of patients during infancy or adolescence. Renal failure and pulmonary, hepatic, and urologic dysfunction are often observed, and systemic fibrosis develops with age. Here, ALMS1 is linked to type 2 diabetes mellitus.