EMERGENCY:A child with MLD who shows rapid neurological deterioration, seizures, or loss of ability to swallow requires urgent assessment. Siblings of a child with confirmed MLD must be tested for ARSA enzyme activity immediately — before symptoms appear. —call040-46324365immediately — 24 hours, 7 days— 24/7
Metachromatic Leukodystrophy (MLD) in Hyderabad: The Myelin-Destroying Disease Where Early Diagnosis Saves Function — and Late Diagnosis Cannot
Expert MRI brain identification of the tiger-stripe leukodystrophy pattern, ARSA enzyme assay, urine sulfatides, ARSA gene sequencing, nerve conduction studies, urgent sibling testing, HSCT referral coordination, international Libmeldy gene-therapy referrals, and supportive / palliative care by the KIMS Neuroscience team at KIMS Neuroscience, Secunderabad, Hyderabad.
MLD is an autosomal recessive lysosomal storage disease caused by severe deficiency of arylsulfatase A (ARSA, gene on chromosome 22q13), which normally breaks down sulfatides in myelin. Sulfatides accumulate in the white matter, peripheral nerves, liver, and kidneys, destroying the myelin sheath. Three forms: late-infantile (~50%, onset 12–24 months, most aggressive), juvenile (onset 4–16 years, cognitive/behavioural changes before motor — misdiagnosed as ADHD), and adult (onset >16 years, psychiatric features misdiagnosed as schizophrenia). Critical staging: Stage 1 (walking with difficulty) = eligible for HSCT or Libmeldy; Stage 2 (unable to walk) = very limited benefit; Stage 3 = no disease-modifying treatment. A rarer form is caused by PSAP mutations (saposin B deficiency): clinically identical disease but normal ARSA enzyme activity — diagnosis requires urine sulfatides and gene sequencing. ARSA pseudodeficiency: the p.Arg247Trp and p.Arg249Trp alleles give low enzyme activity without disease. Libmeldy (atidarsagene autotemcel): EMA approved December 2020 for pre-symptomatic or early Stage 1 late-infantile and early juvenile MLD.
- Tiger stripe / leopard skin MRI — the MLD signature
- T2/FLAIR periventricular white matter signal change with preserved perivascular myelin stripes running through the abnormal areas — producing a striped 'tiger' or spotted 'leopard skin' appearance. The spared perivascular myelin within the signal change is unique to MLD. This MRI pattern seen in a child with motor regression should prompt immediate ARSA enzyme testing.
- ARSA pseudodeficiency — the clinical pitfall
- p.Arg247Trp and p.Arg249Trp ARSA alleles give low enzyme activity on the standard synthetic substrate assay WITHOUT causing MLD. Urine sulfatides distinguish: elevated in true MLD, NORMAL in pseudodeficiency. ARSA gene sequencing confirms. Never diagnose MLD on enzyme assay alone — always confirm with urine sulfatides and gene sequencing.
- PSAP / saposin B deficiency — MLD with normal ARSA
- Mutations in the PSAP gene producing saposin B deficiency cause a disease clinically identical to ARSA-MLD, but with COMPLETELY NORMAL ARSA enzyme activity. If MLD is clinically suspected and the ARSA enzyme is normal, test PSAP gene and measure saposin B. This rare form responds to HSCT in the same way as ARSA MLD.
- HSCT and atidarsagene autotemcel (Libmeldy) — the treatment window
- Pre-symptomatic or Stage 1 (walking with difficulty): HSCT from a matched donor produces near-normal outcomes in late-infantile MLD. Libmeldy (EMA 2020): patient's own HSCs corrected ex vivo with functional ARSA gene, re-infused — supranormal ARSA expression, no donor required. Stage 2 (unable to walk): very limited benefit. Stage 3 (bedridden): no DMT. The sibling of a diagnosed MLD patient must be tested and staged THAT DAY.
- Juvenile MLD mimics ADHD; adult MLD mimics schizophrenia
- Juvenile MLD: declining school performance, behavioural difficulties, personality change preceding motor signs by months to years. Misdiagnosed as ADHD. Adult MLD: psychiatric features (psychosis, personality change) preceding neurological signs by years. Misdiagnosed as schizophrenia. White matter MRI changes are the diagnostic key in both.
- NCS confirms peripheral neuropathy component
- MLD affects BOTH central white matter (MRI) and peripheral nerves (NCS). Absent or reduced deep tendon reflexes + severely reduced NCV on NCS + central white matter signal change = leukodystrophy affecting both central and peripheral myelin = MLD is the first diagnosis. This dual involvement distinguishes MLD from pure central leukodystrophies.
- ARSA enzyme threshold
- ARSA activity ≤0.3 nmol/min/mg protein = severely reduced = MLD. Normal >1.0. Measured in leukocytes (peripheral blood) or dried blood spot.
| Fact | Details |
|---|---|
| Definition | ARSA deficiency (ARSA gene) · Sulfatide accumulation in CNS white matter + peripheral nerves · Three forms: late-infantile (most common, ~50%), juvenile, adult |
| MRI signature | Tiger stripe / leopard skin: T2 periventricular white matter change + spared perivascular myelin stripes within signal-change areas · Pathognomonic for MLD |
| ARSA pseudodeficiency | p.Arg247Trp and p.Arg249Trp alleles · Low enzyme activity without disease · Urine sulfatides normal in pseudodeficiency, elevated in true MLD · Always confirm with gene sequencing |
| PSAP / saposin B deficiency | PSAP gene mutations · Clinically identical to ARSA-MLD · NORMAL ARSA enzyme activity · Test PSAP + saposin B if ARSA normal but clinical picture fits MLD |
| Treatment staging | Stage 1 (walking with difficulty): HSCT or Libmeldy · Stage 2 (unable to walk): very limited benefit · Stage 3 (bedridden): no DMT · Pre-symptomatic sibling: maximum benefit |
| Libmeldy | EMA December 2020 · Autologous HSC gene therapy · For pre-symptomatic or early Stage 1 late-infantile and early juvenile MLD · Supranormal ARSA expression · No donor required |
| Sibling testing | Most urgent action after ANY MLD diagnosis · ARSA enzyme assay on all siblings the SAME DAY · Pre-symptomatic sibling + HSCT/Libmeldy = near-normal life |
About This Condition
Metachromatic Leukodystrophy at a Glance
The essential facts that shape how MLD is recognised, diagnosed, and treated at KIMS — from the lysosomal-storage biology and the autosomal-recessive ARSA genetics, to the India-specific incidence, and the central message that the treatment window closes once myelin destruction has reached Stage 2 or 3.
What it is
Metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal storage disease caused by severe deficiency of the enzyme arylsulfatase A (ARSA). Without adequate ARSA activity, sulfatides — a class of sulfated lipids that are normal components of myelin — cannot be broken down. They accumulate in the white matter of the brain, in peripheral nerves, in the liver, and in the kidneys. The accumulation of sulfatides destroys the myelin sheath, producing progressive neurological deterioration that affects movement, cognition, vision, and eventually all neurological function.
Genetics
Autosomal recessive: both parents carry one defective ARSA gene without symptoms; each pregnancy has a 25% risk of an affected child. Caused by mutations in the ARSA gene on chromosome 22q13.31. Carrier frequency approximately 1 in 40 in most populations. A rarer form is caused by PSAP gene mutations (saposin B deficiency) producing a clinically identical disease with normal ARSA enzyme activity but absent saposin B activator protein.
Incidence in India
MLD incidence is approximately 1 in 40,000–160,000 births globally. In consanguineous populations including parts of India, higher founder mutation rates increase local incidence. MLD is the most common leukodystrophy overall. Because India lacks universal newborn screening, most MLD cases are diagnosed only when symptoms are already present — after the optimal treatment window has closed.
The treatment window
Haematopoietic stem cell transplantation (HSCT) from a matched donor, and gene therapy (Libmeldy — atidarsagene autotemcel, approved in Europe), both work by providing the nervous system with functional ARSA-producing cells. Their benefit requires intact myelin to protect: they slow or halt new myelin destruction but cannot repair already destroyed myelin. This means treatment must occur before significant neurological damage. A child diagnosed at stage 1 (walking, minimal neurological signs) has an excellent chance of a good outcome with HSCT. A child diagnosed at stage 2 or 3 (unable to walk, significant cognitive loss) has little or no benefit.
Emergency
040-46324365
Appointment
040-44885000
Diagnosis at KIMS
A Diagnosis That Arrives One Year Too Late
A 3-year-old girl in Hyderabad who walked at 12 months began to fall frequently at 20 months. By 22 months, her parents noticed her speech was less clear. By 26 months, she could no longer walk without support. By 30 months, she could not stand. She was brought to KIMS at age 3, having been assessed at two other centres and labelled as “cerebellar ataxia of unknown cause.”
At KIMS, the MRI brain immediately suggests the diagnosis: bilaterally symmetric periventricular white matter signal change on T2/FLAIR, with a characteristic “tiger stripe” or “leopard skin” pattern of spared perivascular myelin within the areas of signal change — the MLD signature. Nerve conduction studies show severely reduced conduction velocities, confirming peripheral nerve demyelination alongside the central white matter disease. ARSA enzyme activity in leukocytes: undetectable. ARSA gene sequencing: compound heterozygous mutations. The diagnosis is late-infantile MLD, the most common form.
The conversation that follows is the most difficult in the KIMS leukodystrophy programme. She is classified as stage 3 MLD — unable to walk, significant cognitive regression, unable to stand or support herself. At this stage, HSCT and gene therapy are not indicated: they require sufficient intact myelin to preserve. The window for disease-modifying treatment has closed. The care pathway at KIMS shifts to the best possible supportive management: seizure control, feeding support, physiotherapy for positioning and comfort, and family support.
The equally important part of the consultation: her 6-month-old baby brother. He must be tested immediately for ARSA enzyme activity. If he is affected and pre-symptomatic, HSCT or gene therapy at this stage offers an excellent chance of a near-normal life. The ARSA test is ordered the same day. It returns: severely deficient. He is pre-symptomatic MLD. At KIMS, the HSCT referral is initiated within one week. He undergoes allogeneic HSCT at a specialist paediatric transplant centre. At age 4, he is walking, talking, and developing normally.
Same disease. Same family. Completely different outcomes — determined entirely by when the diagnosis was made relative to symptom onset.
Book a Consultation
Speak directly with The KIMS Neuroscience team and the KIMS MLD specialist team — paediatric neurology, metabolic medicine, neuroradiology, clinical genetics, HSCT referral coordination, palliative medicine, and family counselling under one roof. Sibling testing arranged urgently. No referral required. Monday to Saturday.
040-44885000Acute deterioration: 040-46324365MLD Forms and Clinical Stages
MLD presents in three principal age-defined forms — late- infantile (the most common and most aggressive), juvenile (often misdiagnosed as ADHD or learning disability), and adult (often misdiagnosed as a primary psychiatric disorder). The cards below summarise their onset age, clinical course, and treatment implications at KIMS.
Late-infantile MLD
Onset 12–24 months (peak 18 months) — most common ~50%Most common form (~50% of all MLD). Begins with gait ataxia and regression of walking. Progresses to loss of all voluntary movement, quadriplegia, cortical blindness, severe intellectual disability.
Peripheral neuropathy present from early stages (absent reflexes, slow nerve conduction). Death usually by age 5–10.
HSCT: pre-symptomatic or stage 1 only. Gene therapy (Libmeldy): pre-symptomatic or early stage 1.
Median survival without HSCT: 3–5 years post-diagnosis.
Juvenile MLD
Onset 4–16 years — second most commonInsidious onset with cognitive and behavioural changes at school (declining performance, behavioural difficulties) before motor signs.
Motor regression follows. Longer course than late-infantile.
HSCT: effective if given early (pre-symptomatic or minimal symptoms). Gene therapy: being evaluated.
Key message: cognitive/behavioural changes in school years may be juvenile MLD, not ADHD.
Adult MLD
Onset >16 years — rarest, often misdiagnosedRarest form. Psychiatric features (psychosis, personality change) or cognitive decline may precede motor signs by years.
Often misdiagnosed as schizophrenia or dementia. White matter MRI changes are diagnostic. Peripheral neuropathy present.
HSCT in early adult MLD can slow progression.
Diagnosis often delayed significantly — adult MLD is typically labelled as a primary psychiatric disorder for years before MRI clarifies.
Clinical Features
The clinical profile of MLD differs by age of onset — from motor regression and peripheral neuropathy in late-infantile MLD, to cognitive and behavioural decline misdiagnosed as ADHD in juvenile MLD, to the psychiatric presentations that delay adult MLD diagnosis for years.
Motor regression — the earliest sign in late-infantile MLD
A child who had been walking loses the ability to walk. Falls increase, coordination deteriorates, then standing becomes impossible. This motor regression — the loss of previously acquired milestones — is the cardinal sign that distinguishes MLD from a static developmental condition. Any child who loses motor milestones they had previously achieved requires urgent investigation. In late-infantile MLD, motor regression typically begins 6–12 months after the affected milestones were achieved.
Peripheral neuropathy — the clue that points to MLD
MLD affects both the central white matter and the peripheral nerves. Deep tendon reflexes are reduced or absent (areflexia) from peripheral nerve demyelination, even in early disease. Nerve conduction studies show dramatically slowed conduction velocities. This combination of central white matter disease (on MRI) + peripheral neuropathy (on NCS) is a specific pointer to leukodystrophies affecting both central and peripheral myelin — of which MLD is the most common. It distinguishes MLD from pure central leukodystrophies like Alexander disease.
Cognitive and behavioural decline in juvenile MLD
In juvenile MLD, the first signs are often cognitive and behavioural: declining school performance, loss of previously acquired reading or arithmetic ability, personality change, disinhibition, or withdrawal. These changes precede motor signs by months to years and are frequently attributed to attention deficit disorder, learning disability, or behavioural problems, causing diagnostic delays of several years. Any school-age child with progressive cognitive decline (not stable difficulties that were always present) requires MRI brain and ARSA enzyme testing at KIMS.
Adult MLD mimicking psychiatric illness
Adult-onset MLD most commonly presents with psychiatric features: personality change, paranoia, emotional blunting, or frank psychosis — sometimes treated as schizophrenia for years before neurological signs develop. The MRI white matter changes are eventually identified. ARSA enzyme testing confirms the diagnosis. Adult MLD has a longer and more variable course than infantile forms, and early HSCT in selected adults with minimal neurological disability has produced some slowing of progression.
Diagnosis at KIMS — MRI, ARSA Enzyme, Urine Sulfatides, Gene Sequencing & NCS
MLD diagnosis at KIMS combines MRI brain identification of the tiger-stripe pattern, the ARSA enzyme assay (the biochemical gold standard), urine sulfatides to distinguish true MLD from ARSA pseudodeficiency, ARSA gene sequencing for definitive diagnosis and family testing, and nerve conduction studies to document the peripheral neuropathy.
MRI brain — the characteristic white matter pattern
T2/FLAIR hyperintensity in the periventricular and deep white matter, bilateral and roughly symmetric, with the characteristic "tiger stripe" pattern: areas of affected white matter interspersed with preserved perivascular myelin stripes creating a striped appearance. In late-infantile MLD: frontal predominance initially, spreading posteriorly. In juvenile MLD: more diffuse involvement from onset. Cerebellar white matter involvement develops later. Cortical grey matter and basal ganglia are spared in early MLD. MR spectroscopy shows elevated choline (from myelin breakdown) and reduced NAA (from neuronal loss).
ARSA enzyme activity assay — the biochemical test
ARSA enzyme activity measured in leukocytes (white blood cells from a peripheral blood sample) or dried blood spot. Severely reduced ARSA activity (≤0.3 nmol/min/mg protein, compared to normal >1.0) confirms MLD. Important: a minority of healthy people have "pseudodeficiency" of ARSA (reduced enzyme activity but normal sulfatide metabolism, no disease) — genetic testing is always combined with enzyme assay to confirm true deficiency. At KIMS, ARSA testing is arranged urgently (2–4 week turnaround at reference metabolic laboratory).
Urine sulfatides — increased in MLD
Measurement of sulfatide levels in urine provides additional biochemical confirmation. Sulfatides are elevated in MLD because the ARSA enzyme cannot break them down. This test distinguishes MLD from ARSA pseudodeficiency (normal urine sulfatides in pseudodeficiency, elevated in true MLD).
ARSA gene sequencing — for definitive diagnosis and family testing
ARSA gene panel sequencing identifies the specific mutations in the patient. This enables: (1) confirmation of the diagnosis; (2) carrier testing of parents and relatives; (3) prenatal diagnosis in future pregnancies; (4) newborn / pre-symptomatic sibling testing when a family mutation is known. At KIMS, ARSA gene sequencing is arranged alongside the enzyme assay.
Nerve conduction studies — peripheral neuropathy documentation
NCS at KIMS documents the peripheral neuropathy component: dramatically reduced motor and sensory conduction velocities (demyelinating pattern, similar to the slowest CMT velocities), reduced or absent evoked potentials. This is important for MLD staging, HSCT eligibility assessment, and family counselling.
Treatment
Treatment at KIMS — Eligibility, HSCT, Gene Therapy & Supportive Care
MLD treatment at KIMS is built around four integrated pieces — eligibility staging, HSCT coordination, international Libmeldy gene-therapy referral, and supportive management for patients beyond the disease-modifying window.
Eligibility, HSCT, Libmeldy gene therapy & supportive care
Who Is Eligible for Disease-Modifying Treatment?: MLD treatment eligibility criteria at KIMS: Pre-symptomatic affected sibling: maximum benefit — HSCT or gene therapy indicated urgently. Stage 1 (minimal symptoms — walking with difficulty, early cognitive change): good benefit from HSCT; Libmeldy gene therapy eligible in Europe if early-stage juvenile or late-infantile. Stage 2 (unable to walk, significant cognitive loss): very limited benefit from HSCT; generally not indicated. Stage 3 (bedridden, severe intellectual disability): no disease-modifying treatment indicated; supportive / palliative care. The single most important action at any MLD diagnosis: test all siblings immediately and refer pre-symptomatic or Stage 1 cases for HSCT assessment.
Haematopoietic Stem Cell Transplantation (HSCT): HSCT from a matched related or unrelated donor provides the recipient with donor-derived monocytes and macrophages that migrate into the CNS and produce functional ARSA enzyme. This enzyme corrects the metabolic defect in the CNS over months to years. The procedure itself (conditioning chemotherapy + stem cell infusion) takes place at a specialist paediatric haematology-oncology centre. At KIMS, we identify HSCT-eligible MLD patients, arrange urgent metabolic staging, and coordinate expedited referral to specialist HSCT centres in India. HSCT in pre-symptomatic late-infantile MLD: most children develop near-normally. HSCT in Stage 1 late-infantile MLD: most stabilise; some continue to progress slowly. HSCT in juvenile MLD (early stage): good stabilisation of cognitive function.
Gene Therapy — Libmeldy (Atidarsagene Autotemcel): Libmeldy is a gene therapy approved by the European Medicines Agency (EMA) in 2020 for pre-symptomatic or early-symptomatic late-infantile and early juvenile MLD. The patient's own haematopoietic stem cells are harvested, genetically corrected ex vivo (a functional ARSA gene is inserted using a lentiviral vector), and re-infused. The corrected cells produce supranormal levels of ARSA, halting myelin destruction. Clinical trial data show excellent outcomes in pre-symptomatic patients — almost all maintain near-normal neurodevelopment. Libmeldy is not yet approved in India, but KIMS coordinates referral to eligible international treatment centres for appropriate patients.
Supportive Management at KIMS: For patients not eligible for disease-modifying treatment: seizure management (levetiracetam, valproate, or clonazepam as appropriate to seizure type); spasticity management (baclofen, tizanidine, botulinum toxin); nutritional support (gastrostomy when oral feeding becomes unsafe); physiotherapy for positioning, contracture prevention, and comfort; communication support (augmentative communication); and palliative care integration from the point of disease-modifying treatment ineligibility.
Related Conditions
Metachromatic leukodystrophy belongs to the family of hereditary polyneuropathies and leukodystrophies evaluated and managed at KIMS Neuroscience:
FAQs
Frequently Asked Questions
Metachromatic leukodystrophy destroys myelin silently before symptoms appear. The sibling of a child with MLD who has not yet been tested may still be in the pre-symptomatic window. That window closes.
At KIMS Neuroscience, Secunderabad, Hyderabad, MLD diagnosis is expedited: ARSA enzyme assay, urine sulfatides, ARSA gene sequencing, MRI, and NCS — all coordinated urgently. Pre-symptomatic and Stage 1 patients are referred immediately for HSCT. Call 040-44885000 to book an MLD assessment. Sibling testing urgent line: 040-44885000.
International enquiries: info@kimsneurosciences.com