Madaan Priyanka, Jauhari Prashant, Chakrabarty Biswaroop, Kumar Atin, Gulati Sheffali
Department of Pediatrics, Child Neurology Division, All India Institute of Medical Sciences, New Delhi, India.
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India.
Neuropediatrics. 2019 Oct;50(5):318-321. doi: 10.1055/s-0039-1692646. Epub 2019 Jul 18.
Metachromatic leukodystrophy (MLD) is a rare sphingolipid storage disorder caused by arylsulfatase A (ARSA) deficiency, resulting in central and peripheral demyelination. However, an uncommon form of MLD caused by saposin B deficiency is also described (around 10 mutations reported till date). MLD is a systemic disorder affecting the central and peripheral nervous system, gall bladder, and kidneys. Acute flaccid paralysis as the initial clinical presentation is previously known in ARSA-deficient MLD. Hereby, we report a child with acute flaccid paralysis with brain magnetic resonance imaging showing nonspecific periventricular leukodystrophy. He had progressive cognitive decline with gall bladder polyposis. ARSA levels were within normal limits. Leukodystrophy gene panel revealed a homozygous pathogenic deletion (Lys227del variant) in prosaposin () gene. Hence, a final diagnosis of saposin B-deficient MLD was established. The index case highlights the importance of clinical and electrophysiological clues in the diagnosis of such atypical presentations of MLD.
异染性脑白质营养不良（MLD）是一种罕见的鞘脂贮积病，由芳基硫酸酯酶A（ARSA）缺乏引起，导致中枢和外周脱髓鞘。然而，也有由鞘脂激活蛋白B缺乏引起的一种不常见形式的MLD被描述（迄今为止报道了约10种突变）。MLD是一种影响中枢和外周神经系统、胆囊和肾脏的全身性疾病。急性弛缓性麻痹作为最初的临床表现先前在ARSA缺乏的MLD中是已知的。在此，我们报告一名患有急性弛缓性麻痹的儿童，其脑部磁共振成像显示非特异性脑室周围白质营养不良。他伴有胆囊息肉且认知功能进行性下降。ARSA水平在正常范围内。白质营养不良基因检测显示在鞘脂原（）基因中有一个纯合致病性缺失（Lys227del变异）。因此，最终确诊为鞘脂激活蛋白B缺乏的MLD。该病例突出了临床和电生理线索在诊断此类非典型MLD表现中的重要性。
