Autosomal recessive refers to type of inheritance pattern in which a certain disease develops because both parents carry the trait on their genes. According to MedlinePlus, genes are presented in pairs that express certain traits. A defect in one of the genes can be passed on to a child during fertilization. In fact, a child has a 25 percent chance of developing a certain disease if both parents are carriers for the disease in question.
Tay-Sachs Disease
Tay-Sachs disease is an autosomal recessive disease affecting the nervous system. According to MedlinePlus, symptoms of Tay-Sachs disease include deafness, seizures, delayed growth, irritability, fatigue, dementia and blindness. Tay-Sachs disease can also lead to a loss of motor skills, decreased eye contact, paralysis and irritability.
Tay-Sachs occurs as a result of a defect in the gene called chromosome 15. Both parents carry this defect and pass it on to their child. Specifically, Tay-Sachs disease occurs when the body doesn't have a certain enzyme (protein) called hexaminodase A, which is necessary to breakdown a ganglioside chemical. So, these gangliosides (a type of nerve tissue) accumulate in the nerve cells, says MedlinePlus.
Unfortunately, no treatment is available for Tay-Sachs disease and children die by the time they are four or five years old.
Usher Syndrome
The National Library of Medicine says that Usher syndrome is responsible for 3 to 6 percent of childhood deafness and 50 percent of blindness and deafness in adults. Specifically, this is an autosomal recessive disease in which there is a mutation in such genes called CDH23 and CLRN1.
There are three types of Usher syndrome: type 1, type 2 and type 3. Type 1 Usher syndrome sufferers are born deaf or lose their hearing within the first year of life, says the National Library of Medicine. Type 2 sufferers are typically deaf at birth and lose their vision during the teen or adult years. Type 3 sufferers have hearing and vision loss within 10 to 20 years of life.
No cure for Usher syndrome exists.
Autosomal Recessive Polycystic Kidney Disease
The Polycystic Kidney Foundation says that autosomal polycystic kidney disease is a rare condition that strikes 1 out of every 20,0000 people in the United States. Specifically, this is a disease in which cysts form all over the kidneys and lead to a decline in kidney function. Symptoms of this disease include elevated amounts of urine and must frequently urinate to eliminate all the urine. A sufferer also has high blood pressure and can develop gastrointestinal bleeding and an enlarged spleen.
Treatment often involves a kidney transplant.
