**Core Concept:** Sandhoff's disease is a rare lysosomal storage disorder caused by deficiency of enzymes involved in lipid catabolism. The disease is named after the German physician Hans Sandhoff who first described it in 1963. The correct enzyme is β-hexosaminidase, which is responsible for the degradation of glycosphingolipids and glycosaminoglycans (GAGs) within lysosomes.

**Why the Correct Answer is Right:** In Sandhoff's disease, the deficiency of β-hexosaminidase enzyme leads to the accumulation of GAGs, particularly dermatan sulfate and heparan sulfate, in various tissues and organs. These accumulated GAGs cause progressive neurological dysfunction and organ failure. The enzyme deficiency results from mutations in the HEXB gene, which encodes the β-hexosaminidase β subunit.

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because the correct answer is β-hexosaminidase, not α-hexosaminidase. α-hexosaminidase is another enzyme involved in GAG degradation, but it is not the enzyme responsible for Sandhoff's disease.

B. This option is wrong because it talks about the enzyme α-mannosidase, which is unrelated to Sandhoff's disease. α-mannosidase is involved in glycoprotein degradation, while Sandhoff's disease is caused by deficiency of β-hexosaminidase.

C. This option is incorrect because it refers to lysosomal acid phosphatase, which is not the enzyme responsible for Sandhoff's disease. Lysosomal acid phosphatase is an enzyme involved in the degradation of phosphoric esters and phosphomonoesters, while Sandhoff's disease is caused by deficiency of β-hexosaminidase.

D. This option is incorrect because it mentions acid β-galactosidase, which is unrelated to Sandhoff's disease. Acid β-galactosidase is involved in the breakdown of galactose-containing glycoproteins and glycolipids, while Sandhoff's disease is caused by deficiency of β-hexosaminidase.

**Clinical Pearl:** Sandhoff's disease is an example of a lysosomal storage disorder, which is a group of genetic disorders characterized by the accumulation of undigested waste products in the lysosomes of cells due to enzyme deficiencies. The enzyme deficiency in Sandhoff's disease results in progressive neurological deterioration and multisystem involvement, including skeletal, cardiac, and ocular manifestations. Early diagnosis and treatment can significantly improve the quality of life and survival of affected individuals.