Alström syndrome is a rare, progressive genetic disorder, with characteristic deafness, obesity, and visual problems in children, and diabetes with insulin resistance (type 2) and kidney failure in adults. In infancy, the earliest signs are usually extreme photophobia (light sensitivity) and nystagmus (a back-and-forth movement of the eyes). Another early sign may be dilated cardiomyopathy (an enlarged heart) and congestive heart failure in infants less than one year of age. For the first year of life, infants with Alström syndrome gain excessive weight, leading to obesity. Numerous organ systems may be affected later, resulting in blindness, hearing impairment, heart failure, diabetes mellitus type 2, liver disease, pulmonary fibrosis, renal (kidney) failure, and urological dysfunction.
Alström syndrome is caused by mutations or defects in the Alström syndrome 1 or ALMS1 gene, which provides instructions for making a protein with a currently unknown function. Researchers believe that the protein may play a role in hearing, vision, regulation of body weight, and functions of the heart, kidney, lungs, and liver. It may also affect how the pancreas regulates insulin, a hormone that helps control blood sugar levels. More than 80 mutations in the ALMS1 gene have been identified in people with Alström syndrome. Most of these mutations lead to the production of a dysfunctional version of the ALMS1 protein.
Alström syndrome is inherited, or passed down among family members, as an autosomal recessive trait. This means that two copies of the causative gene must be inherited for the disease to occur.
Alström syndrome is extremely rare, with only about 425 cases recorded worldwide. Its exact prevalence is unknown, but the syndrome is more common among people of French-Acadian heritage.
ALMS, ALMS1 human, ALSS, Alström-Hallgren syndrome, blindness, cardiomyopathy, deafness, KIAA0328.