Causes and risk factors
The disease is caused by degeneration in the white matter of brain and CNS. Four types of metachromatic leukodystrophy occur – Late infantile occurring between ages 6 months and 2 years, early juvenile occurring between ages 3 and 6, late juvenile occurring between ages 6 and 16, adult form occurring at age 17 or older. Metachromatic leukodystrophy is an autosomal recessive disorder. This means that a person must receive the defective gene from both parents in order to develop this condition. Deficiency of a lipid (fat) breaking enzyme, (viz., lysosomal enzyme sulfatide sulfatase) causes lipids to build up in the brain, spinal cord, and peripheral nerves due to which they progressively lose function.
Clinical presentation
Patient presents with behavioral changes, gait disturbances, memory problems, reduced attention span, speech disturbances, decline in school performance, loss of motor developmental milestones. Seizures may occur. The early juvenile form includes the following – clumsiness, loss of previously achieved skills, decline of intellect. Tremors may occur. The late juvenile and adult forms include signs and symptoms like decreased performance at work or school, loss of memory, psychosis, or gradual loss of motor skills.
Investigations
Medical history by the patient and clinical examination by the doctor helps in diagnosis. Blood tests to measure levels of the enzyme lysosomal enzyme sulfatide sulfatase. Urine tests to test for buildup of lipids is required. Genetic testing is recommended. Nerve conduction study to look for peripheral nerve damage is advised. MRI of the brain is done. Psychological testing to assess the brain function is done.
Treatment
There is no effective treatment or cure for this condition. Possible treatment options include bone marrow transplant, gene therapy.
Complications
Complications such as reduced lifespan, dementia can occur.
When to Contact a Doctor
One must consult a doctor if the child is showing symptoms such as behavioral changes, growth delays, learning difficulties, etc.
Prevention
Genetic counseling must be done. Tests can be carried out on the amniotic fluid in the prenatal period (during pregnancy) to detect the enzyme deficiency causing MLD.
Systems involved
CNS, locomotor system
Organs involved
Brain, extremities
