Tay Sachs Disease

Tay - Sachs disease is inherited in an autosomal recessive pattern , this means the two alleles in each cell are mutated. The parents of an individual with an autosomal recessive condition each possess one copy of the mutant allele and are unaffected heterozygous carriers. Tay - Sachs disease deteriorates neurons in the brain and spinal cord. The most common form of Tay - Sachs disease is evident in infancy. Infants who inherit the disorder generally appear unaffected until the age of 3 to 6 months, at this stage their rate of development decreases and skeletal muscles weaken. Infants who have inherited the disease lose motor skills (an action which involves using muscles) such as rolling over, sitting and crawling. As the effects of the …show more content…
Without the protein, gangliosides build up in cells. Mutations in the HEXA gene are responsible for the development of Tay - Sachs disease. ‘The HEXA gene provides instructions for making part of an enzyme called beta - hexosaminidase A’ (Genetics Home Reference authors, 2012). The enzyme is situated within the lysosomes, structures in cells responsible for breaking down toxic substances. Inside the lysosomes, beta - hexosaminidase A assists in breaking down the fatty substance, GM2 ganglioside. Mutations in the HEXA gene disturb the activity of beta - hexosaminidase A, which stop the enzyme from breaking down GM2 ganglioside. GM2 ganglioside builds up to toxic levels and is found commonly within neurons in the brain and spinal cord (Genetics Home Reference authors, 2012). Continual damaged caused by the excess of GM2 ganglioside results in the destruction of neurons, this causes symptoms of Tay - Sachs disease. Tay - Sachs disease is caused by a mutated gene on chromosome 15. When two unaffected heterozygous parents give birth, the likelihood that their child will develop Tay - Sachs disease is 25%. In order for a child to inherit Tay - Sachs disease, he/she must receive two chromosomes with the mutant allele, one from each