每日一题_2023.09.04

A 3-year-old girl is brought to her pediatrician because of a progressive loss of motor function and a decline in her cognitive abilities. On physical examination, it is noted that the patient has decreased deep tendon reflexes, truncal ataxia, and a decreased attention span in comparison to the child’s last visit six months ago. The physician knows that her pathology is due to an abnormal accumulation of cerebroside sulfate in her brain, peripheral nerves, kidney, and liver. A deficiency of which of the following enzymes leads to this condition?

一名3岁女孩因运动功能进行性丧失和认知能力下降被带到儿科医师处。体格检查时注意到，与6个月前的最后一次就诊相比，患者的深部肌腱反射降低，躯干共济失调，注意力持续时间缩短。医生知道她的病理是由于硫酸脑苷脂在她的大脑、周围神经、肾脏和肝脏中异常积聚所致。缺乏下面哪个酶会导致这种情况呢?

(A) a-Galactosidase a-半乳糖苷酶A

(B) β-Galactosidase β-半乳糖苷酶

(C) Arylsulfatase A 芳基硫酸酯酶A

(D) Hexosaminidase A 己糖胺酶A

(E) Sphingomyelinase 鞘磷脂酶

答案解析：

芳基硫酸酯酶A将硫脂转化为半乳糖脑苷脂。这种酶在异染性脑白质营养不良(一种常染色体隐性溶酶体贮积病，患者不能降解硫脂，导致硫酸脑苷脂在神经元和非神经元组织中蓄积)患者中缺乏。中枢神经系统和周围神经的髓鞘化异常伴广泛的髓鞘化丧失，导致临床体征。组织学检查可见异染性颗粒。

正确答案：C