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Rare-disease neurology · UK-wide

Alexander disease testing, MRI and GFAP gene testing for a rare leukodystrophy.

Alexander disease is a rare genetic leukodystrophy caused by GFAP gene mutations. Diagnosis combines characteristic brain MRI features with confirmatory GFAP gene sequencing. Modern pathway: paediatric or adult neurology consultation, brain MRI, and genetic testing.

The key facts
A neuroradiologist reviewing a brain MRI for Alexander disease

Why patients choose us

  • 01

    The right hands

    We route you to a consultant neurologist and neuroradiologist experienced in leukodystrophies — the same clinicians who scan you, read the study, and confirm the genetic result together.

  • 02

    A pathway, not a scan

    Brain MRI, GFAP gene sequencing and genetic counselling — arranged as one coordinated workup, not a list of loose appointments.

  • 03

    Independent, and free

    We are paid by no clinic, so the recommendation is impartial and costs you nothing.

Key facts

What Alexander disease is, in six lines.

A snapshot before the detail — the definition, the three clinical forms, how the diagnosis is made and what treatment looks like today.

  • Definition

    A rare autosomal-dominant leukodystrophy caused by mutations in the GFAP gene, affecting astrocytes in the central nervous system.

  • Three forms

    Infantile, juvenile and adult onset — with markedly different clinical presentations and progression.

  • Characteristic brain MRI

    Frontal-predominant white-matter changes, basal ganglia and brainstem involvement — van der Knaap criteria.

  • GFAP gene sequencing

    A single blood test confirms the diagnosis in the vast majority of cases.

  • No disease-modifying treatment yet

    Care is supportive and multidisciplinary — the priority is symptom control and quality of life.

  • Genetic counselling essential

    Autosomal-dominant inheritance means cascade testing and reproductive counselling matter for the whole family.

The diagnosis pathway

From consultation to confirmed diagnosis — what happens, in order.

A rare-disease workup that stays coordinated, so nothing important gets missed between appointments.

  1. 01

    Before

    Neurology consultation

    A paediatric or adult neurologist takes the history, reviews prior imaging and frames the working differential.

  2. 02

    Before

    Detailed family history

    Three-generation pedigree — leukodystrophies, unexplained early death, epilepsy, developmental regression.

  3. 03

    Before

    Neurological examination

    Bulbar function, tone, gait, palatal myoclonus (adult form), developmental milestones (paediatric).

  4. 04

    Tests

    Brain MRI (van der Knaap criteria)

    A dedicated leukodystrophy protocol looking specifically for the frontal-predominant pattern typical of Alexander disease.

  5. 05

    Tests

    GFAP gene sequencing (blood test)

    A single venous sample sent to an accredited genetics laboratory — the confirmatory test.

  6. 06

    Tests

    Cerebrospinal fluid analysis

    Considered for adult-onset forms where the MRI picture is atypical or another cause needs excluding.

  7. 07

    After

    Genetic counselling

    Results are explained by a clinical geneticist, with cascade testing offered to at-risk relatives.

Typical end-to-end: 2–6 weeks from consultation to confirmed genetic result.

What imaging shows

The MRI signature — and the genetic result that confirms it.

Alexander disease has a distinctive MRI fingerprint. Recognising it is what triggers the GFAP gene test that confirms the diagnosis.

  • Frontal-predominant white-matter disease

    The hallmark MRI signature — extensive frontal lobe involvement out of proportion to elsewhere.

  • Periventricular garland-like lesions

    A characteristic rim of high signal running along the lateral ventricles.

  • Basal ganglia involvement

    Signal change and, in some forms, atrophy of the caudate and putamen.

  • Brainstem lesions

    Medulla and midbrain changes — particularly relevant to the adult phenotype.

  • Contrast enhancement (infantile form)

    Enhancement of periventricular structures and basal ganglia is typical in the youngest patients.

  • Adult atrophy pattern

    Bulbar and cerebellar atrophy dominate in later-onset disease, with less florid white-matter change.

  • GFAP mutation confirmation

    The genetic result closes the diagnostic loop and unlocks family testing.

  • Red flag: acute deterioration + hydrocephalus — urgent neurosurgical assessment

    A sudden decline with signs of raised intracranial pressure needs same-day neurosurgical input.

Treatment and next steps

No cure yet — but a great deal to do.

Care is multidisciplinary and symptom-led. The right team, in the right order, changes how families experience the illness.

  • Multi-disciplinary team care

    Neurology, physiotherapy and speech-and-language therapy coordinate the day-to-day plan.

  • Anti-seizure medication if epilepsy

    Targeted regimens where seizures are part of the picture — reviewed regularly.

  • Nutritional support

    Dietetic input, and a feeding tube if bulbar dysfunction makes safe oral intake impossible.

  • Physiotherapy and occupational therapy

    Preserving mobility, function and independence for as long as possible.

  • Symptom-based supportive care

    Spasticity, sleep, autonomic symptoms and pain — each managed on its own terms.

  • Palliative and psychosocial support

    Family-centred care, with early involvement of palliative teams where appropriate.

  • Genetic counselling and cascade testing

    For parents, siblings and children — with reproductive options discussed openly.

  • Enrol in leukodystrophy research registry

    Access to trials and observational studies that will shape future treatment.

Red flags

When to escalate — and when to call for urgent review.

Alexander disease is progressive. These are the changes that shouldn’t wait for the next scheduled appointment.

  • Rapidly progressive infantile form

    A fast decline in the first two years of life warrants urgent tertiary neurology input.

  • Hydrocephalus

    Enlarging head circumference or new signs of raised intracranial pressure.

  • Refractory epilepsy

    Seizures uncontrolled on two or more agents — reassess and re-image.

  • Bulbar dysfunction

    Swallowing or speech difficulties — a swallow assessment matters early.

  • Respiratory failure

    Sleep-disordered breathing or new daytime hypoventilation.

  • Feeding difficulties

    Weight loss, aspiration or prolonged mealtimes — dietetic and SLT review.

  • Palatal myoclonus (adult form)

    A near-specific sign in adult Alexander disease — flag it to your neurologist.

  • Autonomic dysfunction

    Postural symptoms, bladder or bowel changes — screen and treat.

  • Unexpected family cluster

    Two or more relatives with unexplained white-matter disease — refer for genetic review.

Sources

What this guide is built on. Reviewed annually.

Guidance and patient organisations we lean on when writing about Alexander disease.

Reviewed by

Pulse Atlas Editorial Board,

Last reviewed 2026-07-30. Next review due 2027-07-30.

Frequently asked

Everything we get asked about Alexander disease testing.

Quick answers on what the disease is, how it’s diagnosed, whether it’s inherited, and what treatment currently looks like.

  • What is Alexander disease?

    Alexander disease is a rare, progressive leukodystrophy caused by mutations in the GFAP gene. It affects astrocytes — the support cells of the central nervous system — and produces a characteristic pattern of white-matter change on brain MRI.

  • How is Alexander disease diagnosed?

    Diagnosis rests on two pillars: a characteristic brain MRI (van der Knaap criteria — frontal-predominant white-matter change, basal ganglia and brainstem involvement) and confirmatory GFAP gene sequencing from a blood sample.

  • Is Alexander disease inherited?

    It is autosomal dominant, but most infantile cases arise from new (de novo) mutations rather than being inherited. Adult-onset cases more often show a family history. Genetic counselling is essential once a mutation is confirmed.

  • Is there a treatment for Alexander disease?

    There is no disease-modifying treatment yet. Care is supportive and multidisciplinary — anti-seizure medication, physiotherapy, speech and language therapy, nutritional support and, where appropriate, palliative care.

  • What are the three forms of Alexander disease?

    Infantile (onset before age 2, with rapid progression and often hydrocephalus), juvenile (childhood onset, more bulbar and spinal features) and adult (bulbar signs, palatal myoclonus and spinal-cord atrophy, sometimes mimicking multiple sclerosis).

  • Should relatives be tested?

    Once a GFAP mutation is identified, cascade genetic testing is offered to first-degree relatives via a clinical genetics service. Testing is always coupled with genetic counselling — the implications go beyond a lab result.

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In practice, in London

What alexander disease testing looks like on the ground in London

With alexander disease testing, the London question is usually about report turnaround and the radiologist reading it — not whether the scan is available. Public provision for alexander disease testing is competent but constrained by capacity. Private London clinics tend to have shorter diaries and longer appointment slots, so you get the same specialists with more time. For people who’ve been going round in circles with primary care, that first proper conversation is often what shifts things.

A typical private booking for alexander disease testing in London starts with a consultant conversation — sometimes in person on Harley Street or Marylebone, sometimes on video if that suits better. Any imaging or diagnostics happen at a nearby CQC-registered facility, and reports usually land within 24 to 72 hours. The whole loop, from first call to written report, is often done inside a fortnight. For alexander disease testing specifically, the difference between a routine report and a sub-speciality read is where private care earns its keep.

Honesty about expectations is part of the job. A private alexander disease testing appointment in London won’t change the underlying medicine — the guidelines, the consultants, and the equipment are largely the same as on the NHS. What it changes is speed, continuity, and the amount of time you get to actually talk through the findings. Everyone we route to is GMC-registered and works within CQC-regulated facilities.

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