Le Coz P, Assouline E, Vanier M T, Goutières F, Mikol J, Woimant F, Pinard J M, Aicardi J, Haguenau M
Service de Neurologie, Hôpital Lariboisière, Paris.
Rev Neurol (Paris). 1994;150(1):61-6.
The authors report on a Portuguese family with 3 adult brothers affected with GM2-gangliosidosis (B1 variant) in a sibship of 4, and more specifically on one of these brothers with neurological onset at the age of 17. Psychosis, lower motoneuron involvement and dysarthria were predominant in two of the cases; the third had a cerebellar symptomatology. Hexosaminidase A activity, studied in leukocytes, was profoundly deficient when measured using the specific sulfated substrate, but nearly normal using a conventional assay (non-sulfated substrate). These results established the diagnosis of the unusual enzymological form of GM2-gangliosidosis known as the B1 variant, which had so far not been associated with an adult phenotype. Molecular studies are in progress to study genotype/phenotype correlations in this family in comparison with known mutations in the B1 variant and in adult GM2-gangliosidosis. This report also emphasizes that a metabolic etiology, leading to genetic counselling, should be considered in some familial degenerative neurological disorders.
作者报告了一个葡萄牙家庭，在一个4兄弟的家庭中有3个成年兄弟患GM2神经节苷脂贮积症（B1变异型），更具体地说，其中一个兄弟在17岁时出现神经症状。精神病、下运动神经元受累和构音障碍在其中两例中较为突出；第三例有小脑症状。用白细胞检测己糖胺酶A活性时，使用特定的硫酸化底物测量时严重缺乏，但使用传统检测方法（非硫酸化底物）时接近正常。这些结果确立了对GM2神经节苷脂贮积症不寻常酶学形式的诊断，即B1变异型，迄今为止该变异型尚未与成人表型相关联。正在进行分子研究，以比较该家庭与B1变异型及成人GM2神经节苷脂贮积症已知突变的基因型/表型相关性。本报告还强调，在某些家族性退行性神经疾病中应考虑导致遗传咨询的代谢病因。
