Eguchi I, Wakamatsu N, Nakano R, Tsuji S
Department of Neurology, Niigata University.
Nihon Rinsho. 1993 Sep;51(9):2276-80.
Lysosomal beta-hexosaminidase occurs as two major isozymes hexosaminidase A and B. The alpha subunit is encoded by the HEXA gene and the subunit by HEXB gene. Defects in the beta subunit lead to Sandhoff disease. Patients with the defect lack the activity or formation of both hexosaminidase A and B. The disorders are classified according to the age of onset, as infantile, juvenile and adult form. Recent molecular genetic analysis has revealed a 50 kb deletion, 16 kb Alu type deletion, and compound heterozygous with other mutations. In the juvenile or adult type of the disease, point mutation of the HEXB gene, creating a new 3' splice acceptor site. The correlation of the clinical phenotype and the gene abnormalities is discussed.
溶酶体β-己糖胺酶以两种主要同工酶己糖胺酶A和B的形式存在。α亚基由HEXA基因编码，β亚基由HEXB基因编码。β亚基的缺陷会导致桑德霍夫病。患有该缺陷的患者缺乏己糖胺酶A和B的活性或形成。这些疾病根据发病年龄分为婴儿型、青少年型和成人型。最近的分子遗传学分析发现了一个50 kb的缺失、一个16 kb的Alu型缺失以及与其他突变的复合杂合。在青少年或成人型疾病中，HEXB基因发生点突变，产生一个新的3'剪接受体位点。文中讨论了临床表型与基因异常之间的相关性。
