Alström syndrome

Alström syndrome (AS), also called Alström–Hallgren syndrome, is a very rare autosomal recessive genetic disorder characterised by childhood obesity and multiple organ dysfunction. Symptoms include early-onset type 2 diabetes, cone-rod dystrophy resulting in blindness, sensorineural hearing loss and dilated cardiomyopathy. Endocrine disorders typically also occur, such as hypergonadotrophic hypogonadism and hypothyroidism, as well as acanthosis nigricans resulting from hyperinsulinemia. Developmental delay is seen in almost half of people with Alström syndrome. Alström syndrome (AS), also called Alström–Hallgren syndrome, is a very rare autosomal recessive genetic disorder characterised by childhood obesity and multiple organ dysfunction. Symptoms include early-onset type 2 diabetes, cone-rod dystrophy resulting in blindness, sensorineural hearing loss and dilated cardiomyopathy. Endocrine disorders typically also occur, such as hypergonadotrophic hypogonadism and hypothyroidism, as well as acanthosis nigricans resulting from hyperinsulinemia. Developmental delay is seen in almost half of people with Alström syndrome. It is caused by mutations in the gene ALMS1, whose precise function is unknown but is involved in the maintenance of cellular cilia, making Alström syndrome a ciliopathy. At least 239 disease-causing mutations in ALMS1 have been described as of 2015. Alström syndrome is sometimes confused with Bardet–Biedl syndrome, another ciliopathy which has similar symptoms, but Bardet–Biedl syndrome tends to have later onset in its symptoms, includes polydactyly and is caused by mutations in BBSome genes. There is no cure for Alström syndrome. Treatments target the individual symptoms and can include diet, corrective lenses, hearing aids, medications for diabetes and heart issues and dialysis and transplantation in the case of kidney or liver failure. Prognosis varies depending on the specific combination of symptoms, but individuals with Alström syndrome rarely live beyond 50. At least 900 cases have been reported. Prevalence is fewer than 1 in 1,000,000 individuals in the general population, but the disorder is much more common in Acadians, both in Nova Scotia and Louisiana. It was first described by Swedish psychiatrist Carl-Henry Alström and his three associates B. Hallgren, I. B. Nilsson and H. Asander in 1959. Symptoms for Alström syndrome generally appear during infancy with great variability in age. Some of the symptoms include: Alström syndrome is a rare genetic disorder that affects multiple organ systems of the body. This genetic disorder is caused by a mutation of the ALMS1 gene. This gene is located on the short arm of chromosome 2 (2p13.2). The gene mutation is inherited as an autosomal recessive trait. This means both parents have to pass a copy of the ALMS1 gene in order for their child to have the syndrome even though the parents may not show signs or symptoms of the condition. It is still considered to be unknown on how the defective gene causes the disorder. This disease occurs when mutations on the ALMS1 gene have occurred and is usually inherited as an autosomal recessive disorder. The ALMS1 gene encodes instructions for making a protein with an unknown function. Researchers now believe that the protein might play a role in normal sight, hearing, weight regulation and functioning of the heart, kidneys, liver, lungs and pancreas. In addition, the protein is present in almost all of the tissues within the body, which may explain why almost all of the system within the body is affected by the Alström syndrome. The gene is located on chromosome 2, at position 2p13. The ALMS1 gene contains instructions to encode a specific protein known as ALMS1. The protein then is involved in ciliary function, cell cycle control and intracellular transport. In addition, the protein is expressed in all organ tissues of the body. It has a role in the proper function, maintenance and formation of cilia, which are found in all types of cells in the body. Research has been shown that more than 80 mutations in the ALMS1 gene have been identified in individuals that have Alström syndrome. Most of these mutations have led to the production of a dysfunctional version of the ALSM1 protein which are present in tissues, but at low levels. It is possible to clinically detect Alström syndrome in infancy, but more frequently, it is detected much later, as doctors tend to detect symptoms as separate problems. Currently, Alström syndrome is often diagnosed clinically, since genetic testing is costly and only available on a limited basis.