Metachromatic Leukodystrophy

Disease database

Metachromatic Leukodystrophy (MLD) is a rare genetic disorder that affects the nervous system. It is characterized by the progressive degeneration of the white matter in the brain and spinal cord, leading to a variety of symptoms including muscle weakness, developmental delay, seizures, loss of vision, impaired speech, behavioral changes, spasticity, and dementia. MLD is caused by a deficiency of the enzyme arylsulfatase A (ARSA), which is responsible for breaking down a fatty substance called sulfatide. Without this enzyme, sulfatide accumulates in the body and damages the myelin sheath, the protective covering of nerve cells.

Muscle Weakness

One of the early signs of MLD is muscle weakness. Children with MLD may have difficulty walking or may experience muscle stiffness and rigidity. As the disease progresses, muscle weakness becomes more pronounced and can lead to loss of mobility.

Developmental Delay

Children with MLD often experience developmental delays. They may have delayed motor skills, such as sitting up, crawling, or walking. They may also have delayed speech and language development.


Seizures are a common symptom of MLD. These seizures can range from mild to severe and may be difficult to control with medication. Seizures can further contribute to developmental delays and cognitive decline.

Loss of Vision

MLD can cause progressive loss of vision. Children with MLD may experience blurred vision, difficulty seeing in low light, or complete blindness. This vision loss can significantly impact their daily activities and independence.

Impaired Speech

As MLD progresses, individuals may experience impaired speech. They may have difficulty forming words or sentences, and their speech may become slurred or unintelligible. Communication can become increasingly challenging as the disease advances.

Behavioral Changes

MLD can cause significant behavioral changes. Children may become irritable, agitated, or exhibit aggressive behavior. They may also experience mood swings and changes in personality. These behavioral changes can be distressing for both the individual with MLD and their caregivers.


Spasticity refers to muscle stiffness and involuntary muscle contractions. Individuals with MLD may experience spasticity, which can further contribute to difficulties with mobility and coordination.


MLD ultimately leads to dementia, a decline in cognitive function. Individuals may experience memory loss, confusion, and difficulty with problem-solving and decision-making. As the disease progresses, individuals may require full-time care and support.

Treatment and Management

Currently, there is no cure for MLD. However, there are treatment options available to manage the symptoms and improve the quality of life for individuals with the disease.

Enzyme Replacement Therapy

Enzyme replacement therapy (ERT) is a treatment option for MLD. It involves intravenous infusion of the missing enzyme, arylsulfatase A, to help break down the accumulated sulfatide. ERT can slow down the progression of the disease and improve some symptoms, but it is most effective when started early in the course of the disease.

Supportive Care

Supportive care is essential for individuals with MLD. This includes physical therapy to maintain mobility and prevent muscle contractures, occupational therapy to improve daily living skills, and speech therapy to address communication difficulties. Regular monitoring of vision and hearing is also important.

Palliative Care

As MLD is a progressive and ultimately fatal disease, palliative care plays a crucial role in managing symptoms and providing comfort. Palliative care focuses on pain management, symptom control, and emotional support for both the individual with MLD and their family.


Metachromatic Leukodystrophy is a devastating genetic disorder that affects the nervous system. It presents with a range of symptoms including muscle weakness, developmental delay, seizures, loss of vision, impaired speech, behavioral changes, spasticity, and dementia. While there is currently no cure for MLD, treatment options such as enzyme replacement therapy and supportive care can help manage symptoms and improve quality of life. Early diagnosis and intervention are crucial in maximizing the effectiveness of these treatments. It is important for individuals with MLD and their families to have access to comprehensive care and support throughout the course of the disease.

Haroon Rashid, MD
Rate author
Urgent Care Center of Arlington, VA
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