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Metachromatic Leukodystrophy (MLD): Symptoms and Treatment in India
Metachromatic leukodystrophy (MLD) is a rare inherited disorder in which fatty substances called sulfatides damage the protective covering of nerves in the brain and body. Early diagnosis is vital, because the newest treatments work best before symptoms start.
Key facts
Cause
Deficiency of the enzyme arylsulfatase A (ARSA gene)
Inheritance
Autosomal recessive
Mainly affects
Myelin in the brain, spinal cord and peripheral nerves
How common
About 1 in 40,000 to 1 in 160,000 people
Treatment
Gene therapy or stem cell transplant for some, if given early; supportive care
On this page:
Overview
What is metachromatic leukodystrophy?
Metachromatic leukodystrophy (MLD) is a rare genetic disorder of the nervous system. It is caused by a deficiency of the enzyme arylsulfatase A, which normally breaks down fatty substances called sulfatides.
Without the enzyme, sulfatides build up and damage myelin, the protective layer around nerve fibres in the brain, spinal cord and the rest of the body. Signals between the brain and the body slow down, causing a gradual loss of movement, thinking and other abilities.
MLD is one of a group of disorders called leukodystrophies, which affect the white matter of the brain.
Why early diagnosis matters
Timing can change the course of MLD
Gene therapy and stem cell transplants can slow or halt MLD, but only when they are given before symptoms start or very early in the disease. If a child is diagnosed, testing their brothers and sisters straight away can make a life-changing difference.
MLD in India
MLD is estimated to affect about 1 in 40,000 to 1 in 160,000 people worldwide. In India, it is thought to be underdiagnosed, and many children are diagnosed only once their symptoms are advanced.
A child who starts to lose the ability to walk or talk, or whose school performance falls without explanation, should be assessed by a paediatric neurologist. A brain MRI often shows a typical pattern of white-matter damage.
Did you know?
The newest MLD treatments work best before symptoms appear.
This is why younger brothers and sisters of a child with MLD should be tested as early as possible.
Types of MLD
The types are named after the age at which symptoms begin. The earlier the onset, the faster MLD usually progresses.
Late-infantile MLD
The most common form. Symptoms begin before about 2½ years of age, often after a child has learned to walk. Children develop weakness, unsteady walking, muscle stiffness and loss of speech, and the disease progresses quickly.
Juvenile MLD
Symptoms begin between about 2½ and 16 years of age. Early signs often include falling behind at school, behaviour changes and clumsiness, followed by problems with walking and movement. It progresses more slowly than the late-infantile form.
Adult MLD
Symptoms begin after the age of 16, sometimes much later. The first signs are often psychiatric or behavioural, such as personality changes, poor concentration, memory problems or psychosis, with movement problems developing over time.
Signs and symptoms
Symptoms of MLD
Symptoms depend on the type, but as the disease progresses they may include:
- Loss of skills already learned, such as walking or talking
- Muscle weakness, stiffness (spasticity) and unsteady walking
- Decline in school performance, memory or concentration
- Changes in behaviour, mood or personality
- Numbness or pain from damage to the nerves in the arms and legs
- Seizures, difficulty swallowing, and loss of vision and hearing in later stages
When to see a doctor
Consult a doctor, ideally a paediatric neurologist or geneticist, if you or your child has:
- Loss of walking, speech or other skills
- Increasing clumsiness, falls or stiff legs
- An unexplained decline in school or work performance
- A brother or sister diagnosed with MLD
MLD is sometimes mistaken for cerebral palsy, a behaviour disorder or a psychiatric illness, so ask about a brain MRI if symptoms keep getting worse.
Causes
What causes MLD?
MLD is usually caused by changes (mutations) in the ARSA gene, which gives the body instructions to make the enzyme arylsulfatase A. Rarely, it is caused by changes in the PSAP gene, which makes a helper protein called saposin B.
When the enzyme does not work, sulfatides build up in the cells that make and maintain myelin. Over time the myelin breaks down, and nerves can no longer carry signals properly.
How it is inherited
- It is inherited in an autosomal recessive pattern.
- Parents of an affected child are usually healthy carriers of one faulty copy of the gene.
- When both parents are carriers, each pregnancy has a 1 in 4 (25%) chance of an affected child.
- Brothers and sisters should be tested early, as some treatments work only before symptoms start.
How is MLD diagnosed?
A brain MRI often raises the possibility of MLD, and laboratory tests confirm it.
01
Brain MRI
Shows a typical pattern of damage to the white matter of the brain. It is often the first test that suggests MLD.
02
Enzyme test
A blood test measures arylsulfatase A activity. Low activity suggests MLD, but some healthy people also have low levels (pseudodeficiency), so further tests are needed.
03
Urine sulfatide test
Raised sulfatides in the urine help confirm MLD and tell it apart from pseudodeficiency.
04
Genetic test
Confirms changes in the ARSA gene. It also allows testing of brothers, sisters and other relatives, and prenatal testing.
Treatment for MLD
There is no cure yet. Treatments that can slow or stop the disease work only when given very early, so timing is critical.
Gene therapy
A one-time treatment in which the child’s own blood stem cells are given a working copy of the ARSA gene and returned to the body. It can preserve movement and thinking in children treated before symptoms start, or very early in the juvenile form. It is currently available in only a few countries and is extremely expensive.
Approved treatment
- Atidarsagene autotemcel (Libmeldy®/Lenmeldy®)
Stem cell transplant (HSCT)
A bone marrow or cord blood transplant from a healthy donor can slow the disease in some people with juvenile or adult MLD, if it is done before symptoms are advanced. It does not usually help once the disease has progressed.
Supportive and long-term care
A team of specialists helps manage symptoms and keep patients comfortable.
This can include
- Physiotherapy and medicines for muscle stiffness
- Medicines to control seizures and pain
- Feeding support, including feeding tubes
- Palliative care and emotional support for the family
Other treatments, including enzyme replacement therapy given into the spinal fluid, have been studied in clinical trials. Learn more from the MLD Foundation, or search for clinical trials in India.
Clinical trials and studies in India
Studies of metachromatic leukodystrophy (MLD) that are recruiting, or about to recruit, in India. This list updates automatically every day.
There are no studies of metachromatic leukodystrophy (MLD) recruiting in India at the moment. This list is checked every day, so new studies will appear here automatically.
Last checked 10 November 2026 on ClinicalTrials.gov. Always talk to your doctor before joining a study.
Accessing treatment in India
Getting care and support
MLD affects the whole family, and treatment and care can be very expensive. These are the main sources of help.
Government support (NPRD)
The National Policy for Rare Diseases provides financial assistance of up to ₹50 lakh to eligible patients with listed rare diseases, for treatment at a designated Centre of Excellence (COE). Ask your COE whether your diagnosis and treatment plan qualify.
- Visit your nearest COE with all medical reports
- Ask about genetic counselling and testing for siblings
- Assistance is subject to approval
Other sources of help
- State government schemes
- Corporate social responsibility (CSR) funding
- Crowdfunding through the government rare disease portal
- Palliative care services near you
How LSDSS helps
- Connects patients with COEs and specialists
- Guides families through funding applications
- Shares updates on support programmes
- Brings patients and caregivers together
Frequently asked questions
Answers to common questions about metachromatic leukodystrophy (MLD).
Still have a question?
A rare inherited disorder in which a deficiency of the enzyme arylsulfatase A causes fatty substances called sulfatides to build up and damage myelin, the protective covering of nerves in the brain, spinal cord and body.
There are three main types, named after the age at which symptoms begin: late-infantile (before about 2½ years), juvenile (about 2½ to 16 years) and adult (after 16 years).
In young children, the first signs are often unsteady walking, weakness and loss of skills already learned. In older children, they include falling behind at school and behaviour changes. In adults, the first signs are often psychiatric or memory problems.
It depends on the type and on treatment. Without effective treatment, children with late-infantile MLD usually do not survive beyond childhood. People with the juvenile form often live 10 to 20 years after symptoms begin, and those with the adult form may live 20 to 30 years or more after diagnosis. Early treatment can improve the outlook for some patients.
Not yet. Gene therapy and stem cell transplants can slow or halt the disease in some patients, but only if they are given before symptoms start or very early. Once the disease is advanced, care focuses on comfort and quality of life.
It is autosomal recessive. A child is affected when both parents pass on a faulty copy of the ARSA gene. When both parents are carriers, each pregnancy has a 1 in 4 chance of an affected child. Brothers and sisters of an affected child should be tested early.
First, visit your nearest Centre of Excellence (COE) with all medical reports to be evaluated, and ask about testing for brothers and sisters. Second, register with LSDSS for support and the latest information. You can also find information and support from the MLD Foundation.
Other lysosomal storage disorders
LSDSS supports patients and families living with all lysosomal storage disorders.
A fatty substance builds up in nerve cells of the brain and spinal cord.
A fatty substance builds up in nerve cells and, in babies, in other organs and bones.
Waste material builds up in nerve cells, causing seizures and loss of vision.
Living with MLD?
Register with LSDSS for guidance, support and the latest updates. You are not alone.
This page is for general information and awareness only. It does not replace advice from a qualified doctor. Last reviewed: November 2026.