Alstrom syndrome is a rare genetic condition that presents various symptoms affecting different parts of the body. Although most cases are presented in infancy, they can develop this syndrome later in life. Alstrom syndrome is characterized by problems of the heart, loss of vision, hearing abnormalities, type 2 diabetes mellitus and short stature. They are also prone to develop various complications that can affect the liver, kidney and the lungs. Some children may have developmental problems although their intelligence often remains unaffected. The alstrom syndrome affects both the males and female population in equal numbers. Although the exact prevalence of this syndrome is not known, it is estimated to range from 1 in 10,000 to less than 1 in 1,000,000 individuals. Globally only 1200 cases of alstrom syndrome have been reported.
Causes Alstrom syndrome is inherited in an autosomal recessive manner where both the copies of the gene, one from each parent, are defective. The parents may be the carriers of the mutated gene and typically do not exhibit any of the signs associated with this condition. The gene causing alstrom syndrome is ALMS1 which is responsible for the production of a specific protein known as ALMS1 essential for several functions of the body. When this protein becomes absent or dysfunctions, it can affect several organs including the brain. However, the exact function of the ALSM1 protein is not known and is considered to be associated with the cell cycle control and intracellular transport system. As this syndrome tends to vary greatly among the affected individuals, the involvement of additional genetic and environmental factors may also contribute to the development of this condition.
Symptoms The initial symptoms associated with this syndrome in infants include eye sensitivity to light caused by progressive degeneration of the retina. The sensorineural hearing loss occurs in children or in adulthood and is the result of the loss of nerve function where the sound is not properly processed by the brain. The children are often overweight and growth tends to stop after puberty resulting in short stature. Some cases of heart condition occur in infancy or adulthood when the heart muscles are enlarged (dilated cardiomyopathy). As a result, the fluid and blood may accumulate in the lungs causing swelling of the feet, legs and ankles. Type 2 diabetes mellitus may develop in children as the result of ‘insulin resistant’ when the body is unable to process the insulin effectively. The other conditions include digestive disturbances, respiratory problems, high blood pressure and thyroid conditions.
Diagnosis The diagnosis includes a thorough evaluation and identifying features associated with this syndrome. In some cases, the diagnosis may be challenging particularly with the delayed onset of certain features such as diabetes or kidney problem. As these cases exhibit vision problems, an examination of the eye (electroretinogram) is necessary to identify abnormalities affecting the retina. The loss of hearing can be detected with an auditory test. The blood sugar level can diagnose hyperglycemia. The genetic testing can identify the genetic mutation associated with alstrom syndrome.
Treatment There is no specific treatment available for this condition. Often, the treatment focuses on the various symptoms evident in each individual. The coordinated team effort is often required with these individuals and may consist of pediatricians, audiologist, endocrinologists and orthopedists. The vision problem may require surgical intervention to fix the retinal changes depending on the severity. Those with hearing problems can benefit from hearing aids, cochlear implants and speech therapy. A dietary plan should be considered to manage obesity and in the management of diabetes mellitus who additionally may require insulin therapy administered every day. Cardiac conditions can be treated with medications to relax the blood vessels and reduce fluid accumulation. Children attaining puberty should be evaluated and may be treated with recombinant growth hormone to assist their growth. Genetic counseling may also be beneficial for some of these individuals and their families.
References https://ghr.nlm.nih.gov/condition/alstrom-syndrome#diagnosis https://www.ncbi.nlm.nih.gov/books/NBK1267/ https://rarediseases.org/rare-diseases/alstrom-syndrome/ https://www.alstrom.org/what-is-alstrom/
