Orpha Number: 64

Alström syndrome is a multisystemic disorder characterized by cone-rod dystrophy, hearing loss, obesity, insulin resistance and hyperinsulinemia, type 2 diabetes mellitus, dilated cardiomyopathy (DCM), and progressive hepatic and renal dysfunction. Approximately 450 cases have been identified worldwide. The clinical features, age of onset, and severity can vary greatly among and within families. The cone-rod retinal dystrophy usually develops within a few weeks after birth, the first symptoms are nystagmus and extreme photodysphoria or light sensitivity. It is progressive and leads to blindness, usually by the second decade of life. Most patients develop mild-to-moderate slowly progressive bilateral sensorineural hearing loss. Dilated cardiomyopathy manifests in approximately two-thirds of patients, either as infants or as adolescents. Patients are at risk of sudden congestive heart failure at any age. Obesity, insulin resistance and hyperinsulinemia are early and consistent features. Patients have distinctive facial characteristics (deep-set eyes with a rounded face, thick ears, premature frontal balding, and thin hair). Most children have characteristic wide, thick, flat feet, and short stubby fingers and toes with no polydactyly or syndactyly. Slowly progressive nephropathy, hepatic dysfunction, chronic respiratory illness, hypertriglyceridemia, and hypertension are frequent. Most patients demonstrate normal intelligence, although some reports indicate delayed psychomotor and intellectual development. Alström syndrome is caused by mutations in the ALMS1 gene and is transmitted as an autosomal recessive trait. Diagnosis is made on the basis of the clinical features observed, usually without genetic confirmation. The identification of two mutated alleles or a single mutated ALMS1 allele in the presence of typical clinical features would confirm the diagnosis. If the ALMS1 mutations are known, prenatal testing in an unborn at risk should be offered with genetic counseling. Differential diagnosis includes Bardet-Biedl syndrome, Biemond II syndrome, Wolfram syndrome, Cohen syndrome, sporadic infantile DCM, and mitochondrial disorders (see these terms). There is no specific therapy but early diagnosis and intervention can moderate the progression and improve the longevity and quality of life for patients. Management should include vigilant monitoring and treatment of the emerging clinical manifestations. The life span rarely exceeds 40 years.
source: Orphanet