This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lipids, Subject name: Biochemistry
Enzyme deficient in Tay-sach's disease : 
Select and explain. 
A. a galactosidase, B. Hexosaminidase A, C. b galactosidase, D. b glucosidase
B: Hexosaminidase A
Answer: B: Hexosaminidase A 
Explanation: Ans. (b) Hexosaminidase ARef: Harper's Biochemistry, 30th ed. pg. 251* Tay-Sach's disease (also known as GM2 gangliosidosis or hexosaminidase A deficiency) is a rare autosomal recessive genetic disorder.* In its most common variant (known as infantile Tay- Sachs disease), it causes a progressive deterioration of nerve cells and of mental and physical abilities that commences around six months of age and usually results in death by the age of four.