Metachromatic Leukodystrophy: Diagnosis, Treatment, Information

Ian C. Langtree - Writer/Editor for Disabled World (DW)
Published: 2009/04/04 - Updated: 2023/01/31
Topic: Pediatric Disabilities - Publications List

Page Content: Synopsis - Introduction - Main

Synopsis: Metachromatic leukodystrophy (MLD) is a hereditary degenerative disease transmitted as an autosomal recessive due to sulfatase, a deficiency with excess accumulation of sulfated lipids responsible for metachromasia in various tissues. Diagnosis of MLD includes MRI to identify lesions and atrophy in the brain's white matter that is characteristic of MLD. Urine tests usually show elevated sulfatide levels.

Introduction

Metachromatic Leukodystrophy Alternate Names: Arylsulfatase A Deficiency (ARSA), Cerebroside Sulfatase Deficiency, Metachromatic Form of Diffuse Cerebral Sclerosis, Metachromatic Leukoencephalopathy, Scholz-Bielchowsky-Henneberg Diffuse Cerebral Sclerosis, Scholz-Greenfield Disease, Sulphatide Lipidosis, Sulphatidosis, Van Bogaert-Nijssen Disease

The U.S. Social Security Administration (SSA) has included Metachromatic Leukodystrophy (MLD) - Late Infantile as a Compassionate Allowance to expedite a disability claim.

Main Item

MLD impairs the growth or development of the myelin sheath, the fatty covering that acts as an insulator around nerve fibers.

Late infantile form, the most common MLD, usually begins in the second year of life (ranges 1-3 years). After normal early development, the infant displays irritability and unstable walking. Developmental milestones, such as language development, are not met, and muscle wasting eventually leads to spastic movements, then profound weakness. Seizures usually occur, followed by paralysis and dementia. Children may become comatose.

Diagnosis of MLD includes MRI to identify lesions and atrophy in the brain's white matter characteristic of MLD. Urine tests usually show elevated sulfatide levels. Some psychiatric disorders coupled with difficulty walking or muscle wasting suggest the possibility of MLD. Blood testing can show the reduced activity of the ARSA enzyme.

Deficiency of the ARSA enzyme alone is not proof of MLD because a substantial ARSA deficiency without any symptoms or clinical consequences is frequent in the general population. During diagnosis and genetic counseling, these harmless ARSA enzyme deficiencies must be distinguished from those causing MLD. The only diagnostic test that solves this problem and is definitive for MLD diagnosis is an analysis of the genetic mutation.

No effective treatment is available to reverse the course of MLD. Drug therapy is part of supportive care for symptoms such as behavioral disturbances, feeding difficulties, seizures, and constipation. Bone marrow transplantation has been tried, and there is evidence that this treatment might slow the progression of the disease. In infants, during a symptom-free phase of the late infantile form, the neurocognitive function may be stabilized, but the symptoms of motor function loss progress.

The prognosis for MLD is poor. In young children with MLD late infantile form, progressive loss of motor and cognitive functions is rapid. Death usually results within five years after the onset of clinical symptoms.

Author Credentials: Ian was born and grew up in Australia. Since then, he has traveled and lived in numerous locations and currently resides in Montreal, Canada. Ian is the founder, a writer, and editor in chief for Disabled World. Ian believes in the Social Model of Disability, a belief developed by disabled people in the 1970s. The social model changes the focus away from people's impairments and towards removing barriers that disabled people face daily. To learn more about Ian's background, expertise, and achievements, check out his bio.