Maple syrup urine disease: magnetic resonance imaging findings in three patients.

Aliya Allahwala Aliya Allahwala,Sibtain Ahmed Sibtain Ahmed,Bushra Afroze Bushra Afroze

doi:10.47391/jpma.1341

Aliya Allahwala Aliya Allahwala, Sibtain Ahmed Sibtain Ahmed + Show 1 more

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https://doi.org/10.47391/jpma.1341

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Abstract

Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disorder, caused by branched-chain alpha-ketoacid dehydrogenase (BCKD) deficiency, leading to toxic accumulation of branched-chain amino acids (BCAAs) including leucine, isoleucine and valine and their corresponding a-ketoacids. The diagnosis of MSUD is based on elevated BCAAs and allo-isoleucine in plasma, and branched-chain hydroxyacids and ketoacids in urine. The identification of alloisoleucine >5 µmol/L is considered pathognomonic. Moreover, brain magnetic resonance imaging (MRI) showing atypical signal intensity and oedema is characteristic of MSUD. Recognition of the classical neuro-radiological findings of MSUD is particularly useful in local settings as many healthcare facilities lack the resources to measure Plasma Amino Acids (PAA). We report three cases of MSUD, in whom the disorder was strongly suspected at presentation, based on classical brain MRI findings, which was urgently confirmed by PAA analysis.

Highlights

We report three cases of Maple syrup urine disease (MSUD), in whom the disorder was strongly suspected at presentation, based on classical brain magnetic resonance imaging (MRI) findings, which was urgently confirmed by Plasma Amino Acids (PAA) analysis
Maple syrup urine disease (MSUD, OMIM #248600) is an autosomal recessive inherited metabolic disorder, caused by branched-chain alpha-ketoacid dehydrogenase (BCKD) deficiency, leading to toxic accumulation of branchedchain amino acids (BCAAs) including leucine (LEU), isoleucine (ILE) and valine (VAL) and their corresponding α-ketoacids.[1, 2] BCKD is a multi-enzyme complex, which consists of a decarboxylase, E1
We report three cases of MSUD, in whom the diagnosis was strongly suspected at presentation based on the classical brain MRI findings, which was urgently confirmed by plasma amino acids (PAA) analysis facilitating early introduction of ILE and VAL in the management which resulted in early recovery from metabolic decompensation

Summary

Introduction

Maple syrup urine disease (MSUD, OMIM #248600) is an autosomal recessive inherited metabolic disorder, caused by branched-chain alpha-ketoacid dehydrogenase (BCKD) deficiency, leading to toxic accumulation of branchedchain amino acids (BCAAs) including leucine (LEU), isoleucine (ILE) and valine (VAL) and their corresponding α-ketoacids.[1, 2] BCKD is a multi-enzyme complex, which consists of a decarboxylase, E1. Case # 1: A male child was born at 37 weeks’ gestation to a gravida 5, para 3+1 mother via spontaneous vaginal delivery (SVD) after an uneventful pregnancy to first-cousin parents He presented on the fifth postnatal day with a two-day history of reluctance to feed and lethargy and a seizure-like activity. Brian MRI done during the last episode of stroke-like event revealed abnormal signals in the basal ganglia, posterior limb of internal capsule and brainstem including dorsal part of midbrain, pons and medulla, highly suggestive of MSUD (Figure 1F-1I) This led to urgent PAA analysis, which showed markedly elevated LEU, ILE and VAL with detection of alloisoleucine confirming the diagnosis of MSUD. Clinical and biochemical improvement was achieved in 36 hours of commencement of the treatment

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