Johnson W G, Chutorian A B
Ann Neurol. 1978 Nov;4(5):399-403. doi: 10.1002/ana.410040503.
A new form of hexosaminidase deficiency disease is characterized clinically by mild, juvenile-onset, very slowly progressive cerebellar ataxia with macular cherry-red spots and absence of other findings. Biochemically there is striking hexosaminidase deficiency in serum, leukocytes, and fibroblasts. Hexosaminidase B appears absent, but hexosaminidase A-like and S-like activity is present on starch-gel electrophoresis. We studied hexosaminidase in leukocytes and serum from members of an affected patient's family and traced the enzyme defect through four generations. Leukocyte heat-stabile hexosaminidase in obligate and presumptive carriers was depressed both in specific activity (nanomoles per milligram of protein per hour) and as a percentage of total hexosaminidase. The carrier state was expressed in serum, but overlap with controls made this test unreliable. The similarity of these carriers to carriers of Sandhoff disease suggests that the disorders may be closely related, perhaps as allelic mutations of the hexosaminidase beta subunit. Those involve with screening for Tay-Sachs disease should be aware that persons with an increased percentage of hexosaminidase A--that is, a decreased heat-stabile fraction--may be carriers of hexosaminidase deficiency diseases.
一种新型己糖胺酶缺乏症的临床特征为轻度、青少年起病、进展非常缓慢的小脑共济失调，伴有黄斑樱桃红斑，无其他异常表现。生化检查显示，血清、白细胞和成纤维细胞中存在显著的己糖胺酶缺乏。己糖胺酶B似乎缺失，但在淀粉凝胶电泳上存在己糖胺酶A样和S样活性。我们研究了一名患病患者家庭成员白细胞和血清中的己糖胺酶，并追踪该酶缺陷至四代人。在肯定和可能的携带者中，白细胞热稳定己糖胺酶的比活性（每毫克蛋白质每小时的纳摩尔数）和占总己糖胺酶的百分比均降低。携带者状态在血清中有所表现，但与对照组存在重叠，使得该检测不可靠。这些携带者与桑德霍夫病携带者的相似性表明，这两种疾病可能密切相关，或许是己糖胺酶β亚基的等位基因突变。参与泰-萨克斯病筛查的人员应意识到，己糖胺酶A百分比升高（即热稳定部分降低）的人可能是己糖胺酶缺乏症的携带者。
