5岁男童进行性智力运动功能倒退2.5年

Progressive psychomotor regression for 2.5 years in a boy aged 5 years

摘要:

患儿男，5岁，因进行性智力运动功能倒退2.5年就诊。早期以运动功能倒退为主要表现。早期头颅MRI及家系全外显子测序分析无异常。4岁9月龄后出现认知功能倒退，头颅MRI提示小脑萎缩。重分析基因测序结果发现患儿存在HEXA基因复合杂合突变［NM_000520，c.784C>T(p.His262Tyr)，c.1412C>T(p.Pro471Leu)］，酶学活力检测结果提示患儿该基因编码β-氨基己糖苷酶水平显著下降。该患儿被确诊为青少年型Tay-Sachs病（Tay-Sachs disease，TSD）。TSD临床异质性强，小脑萎缩可能是青少年型TSD患儿诊断的重要线索。同时，根据病情演变适时进行二次基因数据分析可能提高全外显子测序的阳性率。引

Abstract:

A boy, aged 5 years, attended the hospital due to progressive psychomotor regression for 2.5 years. Motor function regression was the main manifestation in the early stage, and brain MRI and whole-exome sequencing (WES) of the family showed no abnormalities. After the age of 4 years and 9 months, the boy developed cognitive function regression, and brain MRI showed cerebellar atrophy. The reanalysis of WES results revealed a compound heterozygous mutation, [NM_000520, c.784C>T(p.His262Tyr]), c.1412C>T(p.Pro471Leu)], in the HEXA gene. The enzyme activity detection showed a significant reduction in the level of β-hexosaminidase encoded by this gene. The boy was diagnosed with juvenile Tay-Sachs disease (TSD). TSD has strong clinical heterogeneity, and cerebellar atrophy may be an important clue for the diagnosis of juvenile TSD. The reanalysis of genetic data when appropriate based on disease evolution may improve the positive rate of WES.