This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pediatrics, environment and nutrition, Subject name: Pathology
[{'content': "Deficinecy of enzyme hexosaminidase, subunit causes - \nSelect and explain. \nA. Tay - Sach's disease, B. Hurler's syndrome, C. Fabry disease, D. Pompe disease", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Tay-Sachs Disease (GM2 Gangliosidosis: Deficiency in Hexosaminidase b Subunit) Gangliosidoses are characterized by accumulation of gangliosides, principally in the brain, as a result of a deficiency of a catabolic lysosomal enzyme. Depending on the ganglioside involved, these disorders are subclassified into GM1 and GM2 categories. Tay-Sachs disease, by far the most common of all gangliosidoses, is characterized by a mutation in and consequent deficiency of the b subunit of enzyme hexosaminidase A, which is necessary for the degradation of GM2. More than 100 mutations have been described; most affect protein folding or intracellular transpo. Referense:Robbins basic pathology pg no:229,230', 'role': 'assistant'}]