Abstract The spinocerebellar ataxia type 2 is a neurodegenerative disease with autosomal dominant inheritance; clinically characterized by progressive cerebellar ataxia, slow ocular saccades, nystagmus, ophthalmoplegia, dysarthria, dysphagia, cognitive deterioration, mild dementia, peripheral neuropathy. Infantile onset is a rare presentation that only has been reported in four instances in the literature. In the present work a boy aged 5 years 7 months was studied due to horizontal gaze-evoked nystagmus, without saccades, ataxic gait, dysarthria, dysphagia, dysmetria, generalized spasticity mainly pelvic, bilateral Babinsky. The mother aged 27 years-old presented progressive cerebellar ataxia, dysarthria, dysmetria, dysdiadochokinesis, limb ataxia and olivopontocerebellar atrophy. The molecular analysis was made by identifying the expansion repeats in tandem by long PCR to analyze the repeats in the ATXN2 gene. We found an extreme CAG expansion repeats of ~884 repeats in the child. We describe a Mexican child affected by SCA2 with an infantile onset, associated with a high number of CAG repeats previously no reported and anticipation phenomenon.

中文翻译：

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脊髓小脑性共济失调2型大规模CAG重复扩增的临床报告：墨西哥儿童重度发病并回顾以往病例

摘要 2型脊髓小脑性共济失调是一种常染色体显性遗传的神经退行性疾病；临床特征为进行性小脑共济失调、缓慢的眼球扫视、眼球震颤、眼肌麻痹、构音障碍、吞咽困难、认知能力下降、轻度痴呆、周围神经病变。婴儿型发病是一种罕见的表现，文献中仅报道过四次。在目前的工作中，研究了一个 5 岁 7 个月的男孩，由于水平凝视诱发的眼球震颤，没有眼跳，共济失调步态，构音障碍，吞咽困难，测距障碍，全身痉挛，主要是盆腔，双侧巴宾斯基。母亲 27 岁，表现为进行性小脑共济失调、构音障碍、辨距障碍、联动运动障碍、肢体共济失调和橄榄桥小脑萎缩。通过长PCR鉴定串联的扩增重复以分析ATXN2基因中的重复来进行分子分析。我们在孩子中发现了大约 884 次重复的极端 CAG 扩展重复。我们描述了一个受 SCA2 影响的墨西哥儿童，婴儿期发病，与大量 CAG 重复相关，以前没有报道和预期现象。