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: Unknown
[{'content': 'Which of the following diseases is a lysosomal storage disease that is associated with the synthesis of abnormal myelin? \nSelect and explain. \nA. Tay-Sachs disease, B. Niemann-Pick disease, C. Metachromatic leukodystrophy, D. Hurler disease', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Metachromatic leukodystrophy is a lysosomal storage disease associated with the synthesis of abnormal my\xadelin. The term leukodystrophy refers to the abnormality in myelin synthesis. Metachromatic leukodystrophy is an autosomal recessive disease characterized by an arylsulfatase. A deficiency, leading to the accumulation of sulfatides in lysosomes that stain positively with periodic acid-Schiff stain and various metachromatic stains. The clinical findings include various visceral lesions, mental retardation, peripheral neuropathy, and abnormal myelination in the central nervous sys\xadtem associated with reactive gliosis. It is diagnosed by the absence of arylsulfatase A in the urine.\nTay-Sachs disease is an autosomal recessive GM2 gangliosidosis characterized by a hexosaminidase (\uf061 \xadsubunit) deficiency and an accumulation of GM2 gan\xadglioside in lysosomes. It is commonly found in Ash\xadkenazi Jews, in which there is a 1 in 30 carrier rate. The patients are normal at birth but develop abnormal\xadities by 6 months of age, including severe mental retardation, blindness (cherry red spot in the macula), and muscle flaccidity. The lipid has a whorled configuration in lysosomes when viewed by electron micros\xadcopy. It is a uniformly fatal disease.\nNiemann-Pick disease is an autosomal recessive ly\xadsosomal storage disease associated with a sphingomye\xadlinase deficiency and the accumulation of sphingomye\xadlin in macrophages and neurons. The type A variant is most common. It is characterized by severe mental retardation, hepatosplenomegaly, deterioration of psy\xadchomotor function, and foamy macrophages. Zebra bodies are noted in the lysosomes when viewed by electron microscopy. The disease is fatal in early life.', 'role': 'assistant'}]