Neuropediatrics 2019; 50(05): 318-321
DOI: 10.1055/s-0039-1692646
Short Communication
Georg Thieme Verlag KG Stuttgart · New York

Saposin B–Deficient Metachromatic Leukodystrophy Mimicking Acute Flaccid Paralysis

Priyanka Madaan
1  Department of Pediatrics, Child Neurology Division, All India Institute of Medical Sciences, New Delhi, India
,
Prashant Jauhari
1  Department of Pediatrics, Child Neurology Division, All India Institute of Medical Sciences, New Delhi, India
,
Biswaroop Chakrabarty
1  Department of Pediatrics, Child Neurology Division, All India Institute of Medical Sciences, New Delhi, India
,
Atin Kumar
2  Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
,
Sheffali Gulati
1  Department of Pediatrics, Child Neurology Division, All India Institute of Medical Sciences, New Delhi, India
› Author Affiliations
Source of funding None.
Further Information

Publication History

04 January 2019

03 May 2019

Publication Date:
18 July 2019 (eFirst)

Abstract

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 (PSAP) 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.