Question

Tay Sachs disease is due to
(a)Sex-linked recessive gene
(b)Sex-linked dominant gene
(c)Autosomal dominant gene
(d)Autosomal recessive gene

Answer 1

Hint: This is a rare disorder passed from parents to child. It's caused by the absence of an enzyme that helps break down fatty substances. Trait often skips generations. Equal number of affected males and females are found.

Complete answer:
Tay Sachs disease is due to Autosomal recessive genes. It is caused by a genetic mutation in the HEXA gene on chromosome 15, which codes for hexosaminidase (an enzyme which serves in lipid metabolism). Trait often skips generations, most affected individuals have unaffected parents but if both parents are affected, all children should be affected. This means that disease is inherited from a person's parents in an autosomal recessive manner. Equal number of affected males and females are found which means that disease is governed by autosomal gene and is inherited independent of sex of individual. If it was a sex linked gene, it’s inheritance would depend on sex of individual.

Additional Information:
Tay-Sachs disease is a rare inherited disorder that progressively destroys nerve cells (neurons) within the brain and spinal cord. The foremost common sort of Tay-Sachs disease becomes apparent in infancy. As the disease progresses, children with Tay-Sachs disease experience seizures, vision and deafness, intellectual disability, and paralysis. Children with this severe infantile sort of Tay-Sachs disease usually live only into infancy. An eye fixed abnormality called a cherry-red spot, which may be identified with an eye fixed examination, is characteristic of this disorder.
Signs and symptoms can be seen in childhood, adolescence, or adulthood and are generally milder than those seen with the infantile form. Symptoms include muscle weakness, loss of muscle coordination (ataxia) and other problems with movement, speech problems, and mental disease. These signs and symptoms vary widely among people with late-onset sorts of Tay-Sachs disease.
So, the correct answer is ‘Autosomal recessive gene’.

Note: The disease is named after British ophthalmologist Warren Tay, who in 1881 first described a symptomatic red spot on the retina of the eye. The treatment of Tay–Sachs disease is supportive in nature. This may involve multiple specialities as well as psychosocial support for the family.