Alstrom syndrome is characterized by progressive cone-rod dystrophy leading to blindness, sensorineural hearing loss, dilated or restrictive cardiomyopathy and child obesity. Type 2 diabetes mellitus is observed in nearly all patients before the second decade. Renal failure, pulmonary, hepatic, and urologic dysfunction are also often observed. Intelligence is typically normal. Wide clinical variability is observed amongst affected individuals, even within the same family.
Homozygous or compound heterozygous mutations in the ALMS1 gene cause Alström syndrome. ALMS1 is widely expressed in tissues that are affected in patients with Alstrom syndrome, including the central nervous, sensorineural, endocrine, cardiopulmonary, reproductive, and urorenal systems, and the location of ALMS1 to centrosomes suggests roles in intracellular trafficking and ciliary function. The majority of mutations identified to date are nonsense and frameshift that are predicted to cause premature protein truncation.