This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Hexosaminidase A deficiency causes: 
Select and explain. 
A. Niemann-pick, B. Tay-Sachs disease, C. Hurler syndrome, D. Gaucher's disease
B: Tay-Sachs disease
Answer: B: Tay-Sachs disease 
Explanation: Ans: b. Tay-Sachs disease [Refs Harper 30th/251; Lippincott 6th/212; Harrison 19th/432e,433eHexosaminidase A deficiency is an enzyme deficiency that causes brain and other nerve cells to die, which can lead to severe neurological and mental problems.Hexosaminidase A (HEX A) deficiency is caused by a deficiency in an enzyme called beta-hexosaminidase A. This enzyme helps break down a paicular fatty acid called GM2 ganglioside.Without adequate amounts of functional enzymes, GM2 ganglioside will build up in nerve cells and cause them to die.There are several forms of HEX A deficiency, including acute infantile (Tay-Sachs disease), juvenile, chronic, or adult-onset forms.