Defects in the HEXB gene which encodes the β-subunit of β-hexosaminidase A and B enzymes, cause a GM2 gangliosidosis, also known as Sandhoff disease, which is a rare lysosomal storage disorder. The most common form of the disease lead to quickly progressing mental and motor decline in infancy; however there are other less severe forms with later onset that can also involve lower motor neurons. The diagnosis of this disease is based on low serum β-hexosaminidases A and B levels and confirmed using genetic test. We report two siblings with compound heterozygous HEXB mutations whose phenotype was extremely mild consisting in stuttering in both cases associated to mild proximal weakness in one of the cases, broadening the clinical spectrum of late onset Sandhoff disease.

编码 β-氨基己糖苷酶 A 和 B 酶的 β-亚基的HEXB基因的缺陷会导致 GM2 神经节苷脂贮积症，也称为 Sandhoff 病，这是一种罕见的溶酶体贮积症。这种疾病最常见的形式会导致婴儿期智力和运动能力迅速下降；然而，还有其他较晚发病的不太严重的形式也可能涉及下运动神经元。本病的诊断基于低血清β-氨基己糖苷酶A和B水平，并通过基因检测确诊。我们报告了两个具有复合杂合 HEXB 突变的兄弟姐妹，其表型极其轻微，包括在两个病例中的口吃与其中一个病例的轻度近端无力相关，扩大了迟发性 Sandhoff 病的临床范围。