Metachromatic Leucodystrophy: A Case Report

Abstract

Metachromatic leukodystrophy (MLD) is an autosomal recessive neurodegenerative disorder characterized by deficient activity of the enzyme arylsulfatase-A. Deficiency of this enzyme results in intralysosomal storage of sphingolipid cerebroside 3-sulfates (sulfatides), which are abundant in myelin and neurons. A pathological hallmark of MLD is demyelination and neurodegeneration, causing various and ultimately lethal neurological symptoms. Its frequency is estimated to be 1/40,000 live births. The disease encompasses three clinical subtypes: late infantile (40% of the patients with MLD), juvenile (40%), and adult (20%). The CaseA four years old male, presented with a three month history of a progressively unsteady gait and deterioration of speech for the same duration. He was apparently well three months back when he started having frequent fall with gradual impairment of walking. Since one and half months back, he was unable to walk even with support. In addition, also had progressive deterioration in his speech. Initially, speech was slurred and dysarthic and then he could speak only a few words with diffi culty. However, hearing and vision seemed to be normal. There was no history of unconsciousness, seizure, bowel and bladder incontinence or head injury. Detailed history revealed that he was born full term at home. Antenatal, perinatal and postnatal history was not signifi cant. His developmental milestones were within normal limits for age prior to the illness. The family history was however signifi cant; Among the four siblings, one sister had similar type of progressive deterioration of motor as well as intellectual function and had died at age of 5 years. Another sister who was eleven years old also had mental sub normality. However, there was no history of consanguinity. On examination, there was no obvious facial dysmorphism. His head circumference was 49.5 cm (10th percentile NCHS) and weight was below 5 th percentile (HCHS) with normal height. He appeared dull and emotionally labile. All cranial nerves were clinically normal. On motor system examination, all extremities were hypotonic with power of 3/5 and absence of deep tendon refl exes. Planters were fl exure in response bilaterally. There were no sensory involvement; however cortical sensation and coordination could not be assessed. Rest of the general and systemic examinations was found to be normal. MRI revealed periventricular and deep white matter high signal areas (T2, NC, and axial view) and Leopard sign in contrast enhancement. CSF fi nding was normal. A diagnosis of MLD was suggested by the family history and clinical presentation. Further, neuroimaging abnormalities were well characterized and consisted of confl uent periventricular white matter abnormalities sparing the arcuate fi bers which have helped to confi rm the diagnosis of MLD. The patient was advised for physiotherapy and regular follow up.

A 5-Year-Old Male Child With Late Infantile Metachromatic Leukodystrophy

“…Deficiency of aryl sulfatase A (a lysosomal enzyme) leads to accumulation of sulfatides within the myelin sheath in the central and peripheral nervous system, resulting in degenerative white matter disease, or metachromatic leukodystrophy. 1,2 The reported incidence varies from 1 in 40 000 to 160 000 individuals, worldwide. 3…”