Overview of Alstrom Syndrome
What Is Alstrom Syndrome?
Alstrom syndrome is an extremely rare genetic disorder that affects many organ systems of the body. It is considered one of the rarest genetic disorders in the world with only several hundred affected individuals. Alstrom syndrome is sometimes confused with Bardet-Biedl syndrome although it usually has a later onset in the life of the patient.
Signs and Symptoms
One of the most striking features of Alstrom syndrome is photophobia, a sensitivity to light, and nystagmus, a rapid movement of the eyes. It is known that patients with Alstrom syndrome experience degeneration of the retina that captures light and sends information to the brain. Individuals suffering from the condition have a difficult time seeing in well-lit situations and might need specially enchanced print and lenses to see correctly. Later in life, individuals may lose the ability to see in dim situations and are left with little or no vision.
A serious condition called cardiomyopathy, or a disorder of the heart muscle, can manifest. The heart has difficulty in pumping blood to all parts of the body which can build up in the lungs, feet, ankles and legs. When this happens, the heart may stop working and go into failure.
Children with Alstrom syndrome also begin to lose hearing ability due to a loss of nerve functioning in the auditory system. This can happen in childhood or early adulthood and can get progressively worse as age increases.
Other signs and symptoms can include short stature, spine curvature, obesity, learning disabilities and type 2 diabetes.
Causes
Mutations in the ALMS1 gene are responsible for Alstrom syndrome. Although the role of the protein made from ALMS1 is unknown it is believed that it plays a role in hearing, vision, and functioning of the heart and other organs.
The protein made is found in specific portions of chromosomes that may have a role in cell division. It is also found in the bases of cilia which are hair-like projections that surround a cell that aid in movement and cellular signaling. Lastly, the product of ALMS1 is thought to have a role in cytoskeletal production and maintenance of cells.
Alstrom syndrome is considered as an autosomal recessive trait, meaning that the mutation occurs in the non-sexual chromosomes. It is recessive meaning that both genes given from the parents must be affected to produce the disorder in offspring.
Diagnosis and Treatment
Diagnosis can occur when organ abnormalities are apparent and discussed with a doctor. Further analysis and sequencing of the ALMS1 gene can verify the genotype of the patient.
As there is no cure for Alstrom syndrome, there are several treatment options available. Patients can receive hearing aids to help with decreased hearing loss. Special glasses and texts can be made to increase vision in patients experiencing degenerative retinas. Medications can be used to combat cardiomyopathy and restore the heart to its normal functioning. Other medications are available to balance out the differing levels of insulin and other hormones to decrease obesity in some patients.
