The genetic disorder that causes the destruction of nerve cells in the brain and spinal cord is called Tay-Sachs disease. This disease can begin as a child, around ages three to six months, and can cause inability to sit, turnover, or crawl. These symptoms are then followed by seizures, inability to move, and loss of hearing. The child dies early in childhood. It is seen that these symptoms occur later in childhood or adulthood, but it is less common and mild in nature. 

This disease is passed down from a parent in an autosomal recessive manner. If the child inherits both of this recessive gene, they are likely to have this disease. The recessive genes cause a mutation when creating the enzyme Betahexosamidase A which leads to toxicity when it causes a build-up of molecules within the cells.

This disease is rare but follows the people of Ashkenazi Jews, French Canadians of the southeast, and Cajuns of Southern Louisana. It is more common in these populations to receive the recessive gene twice. Those whose alleles are both for this recessive disease have the illness. It follows the Mendelian genetics because it is an allele that follows only on the recessive gene and can only cause change if the carrier has two recessive genes for this disease.

 

References

https://en.wikipedia.org/wiki/Tay%E2%80%93Sachs_disease

http://www.primehealthchannel.com/wp-content/uploads/2011/02/Tay-Sachs-Disease.jpg