Metachromatic Leukodystrophy
Metachromatic Leukodystrophy Causes
Metachromatic leukodystrophy results from a deficiency of an enzyme called Arylsulfatase A. The lack or absence of this essential enzyme causes sulfatides to accumulate in multiple tissues throughout the body, eventually destroying the myelin of the nervous system. Metachromatic leukodystrophy is inherited via the autosomal recessive trait.
Metachromatic Leukodystrophy Definition
Metachromatic leukodystrophy or MLD is the most common type of leukodystrophies, a family of genetic disorders that affect myelin growth and development. Myelin is the fatty covering that insulates nerve fibers throughout the central and peripheral nervous systems. Metachromatic leukodystrophy is also alternatively known as Arylsulfatase A deficiency.
Metachromatic Leukodystrophy Diagnosis
Following a physical exam, any or a combination of the following tests may be used to diagnose metachromatic leukodystrophy: blood and urine tests; magnetic resonance imaging (MRI); as well as psychological and cognitive tests.
Metachromatic Leukodystrophy Symptoms and Signs
Metachromatic leukodystrophy comes in late infantile, juvenile, and adult forms. In the late infantile form, children aged 4 or younger may show: loss of motor development milestones; gait disturbances or walking difficulties; behavioral changes; speech disturbances; swallowing and feeding difficulties; memory loss; vision loss; and seizures. If untreated, children with this form of metachromatic leukodystrophy may die at age 5. The juvenile form affects children between 4-10 years of age, and may present with the following symptoms: mental deterioration; impaired school performance; and dementia. The adult form of MLD, which typically begins after the age of 16, manifests as a psychiatric disorder or progressive dementia.
Metachromatic Leukodystrophy Treatment
There is no cure for metachromatic leukodystrophy. Treatment is focused mostly on symptom management and supportive care. Various future treatment options are currently being developed in clinical research settings, including the possibility of gene therapy and enzyme replacement therapy (ERT), substrate reduction therapy (SRT), and potentially an enzyme enhancement therapy (EET).