Abstract
Introduction: Metachromatic leukodystrophy(MLD) is a rare inherited lysosomal disorder caused by autosomal recessive mutations in Arylsulfatase A(ASA) gene which encodes ASA enzyme. The disease is divided into late-infantile, juvenile and adult onset types according to the onset age.
Case: A 20 year-old female patient presented with continuous crying which started two days ago. She had generalized seizures for ten years, required two anti-epileptic drugs to control. Neurological examination revealed generalized spasticity with exaggerated deep tendon reflexes and extensor plantar responses. Her electroencephalogram showed paroxysmal cortical slowing without epileptic activities. Systemic examination and blood biochemistry was unremarkable. Brain magnetic resonance imaging (MRI) yielded abnormal findings, suggesting the diagnosis of MLD. ASA activity in the peripheral blood leukocytes was found to be decreased in a referral laboratory. Genetic examination revealed that the patient had a compound heterozygous mutation of I179S in the PSAP gene. The patient was discharged with partial improvement under quetiapine treatment.
Discussion and Conclusion: MLD is a progressive rare inherited disease caused by a deficiency in the enzyme activity of ASA. Inevitable neurological sequelae develop as the disease progresses. Generalized cortical atrophy and symmetrical extensive hyperintense signal changes in periventricular white matter on MRI, decreased activity of ASA and mutation in the PSAP gene confirm the diagnosis. In conclusion, we report a case with continous pseudobulbar crying, which can be the result of changes on MRI due to MLD.