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# X-linked adrenoleukodystrophy

A genetic disorder that builds up very-long-chain fats in the brain and adrenal glands; it mainly affects males.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [White matter](https://durgical.com/en/anatomy/white-matter-of-telencephalon/)
- [Left adrenal gland](https://durgical.com/en/anatomy/suprarenal-gland/)
- [Right adrenal gland](https://durgical.com/en/anatomy/suprarenal-gland-abdomen/)
- [Corpus callosum](https://durgical.com/en/anatomy/corpus-callosum/)
- [Spinal cord](https://durgical.com/en/anatomy/spinal-cord/)
- [Occipital lobe](https://durgical.com/en/anatomy/superior-occipital-gyri/)

## In biochemistry

- [Lipid chemistry](https://durgical.com/en/biochemistry/topics/lipid-chemistry/)
- [Peroxisomal oxidation (β- and α-oxidation)](https://durgical.com/en/biochemistry/topics/peroxisomal-oxidation/)

## What it is

An X-linked peroxisomal disorder caused by variants in ABCD1, which encodes the ALDP transporter. Very-long-chain fatty acids cannot enter the peroxisome, build up and damage myelin, the adrenal cortex and the [testes](https://durgical.com/en/anatomy/testis/).

## Who gets it

About 1 in 15,000 people worldwide, with a similar frequency in all populations. It is the most common peroxisomal disorder.

## Causes

- Variants in ABCD1 (X chromosome)
- Hemizygous males are affected; many carrier women develop mild symptoms in adulthood

## Risk factors

- Carrier mother or affected male relatives
- Male sex

## Pathophysiology

ALDP (ABCD1) imports very-long-chain acyl-CoAs (C24, C26) into the peroxisome for β-oxidation. Without it they build up in membranes, especially in myelin and the adrenal cortex. In the cerebral form a fast-spreading inflammatory demyelination is triggered; in adrenomyeloneuropathy the long axons of the [spinal cord](https://durgical.com/en/anatomy/spinal-cord/) degenerate slowly. The adrenal cortex stops making cortisol (adrenal insufficiency).

## Classification

- Childhood cerebral form (4–10 years): rapid inflammatory demyelination
- Adrenomyeloneuropathy (adults): progressive spastic paraparesis
- Isolated adrenal insufficiency
- Symptomatic carrier women (mild myelopathy in adulthood)

## Symptoms and signs

- Attention or school problems in a previously healthy boy
- Loss of vision and hearing
- Clumsiness and gait disturbance
- Leg stiffness and weakness in adults
- Tiredness, darker [skin](https://durgical.com/en/anatomy/skin/) and dizziness from adrenal insufficiency

## Red flags

- Rapid neurological decline in a boy
- Adrenal crisis: hypotension, vomiting, hyponatraemia
- Seizures

## Diagnosis

**Clinical**
Suspected with cognitive or behavioural decline in a boy, primary adrenal insufficiency in a young male, or spastic paraparesis in an adult.

**Tests**
Raised plasma very-long-chain fatty acids (C26:0, C24/C22, C26/C22); ABCD1 testing; cortisol and ACTH; on newborn screening, C26:0 lysophosphatidylcholine.

**Imaging**
Brain MRI with parieto-occipital [white matter](https://durgical.com/en/anatomy/white-matter-of-telencephalon/) lesions and splenium of the [corpus callosum](https://durgical.com/en/anatomy/corpus-callosum/) involvement, with contrast enhancement in the active form (Loes score).

## Treatment

**Procedure**
Haematopoietic stem cell transplant (or gene therapy) in the early cerebral form

**Medical**
Glucocorticoid replacement for adrenal insufficiency

**Follow-up**
Regular MRI surveillance in symptom-free boys to catch the cerebral form in time

**Rehabilitation**
Rehabilitation and spasticity management in adrenomyeloneuropathy

## Complications

- Severe neurological disability and vegetative state in the cerebral form
- Adrenal crisis
- Paraparesis and incontinence

## Prognosis

Untreated, the cerebral form progresses to severe disability within a few years; early transplant can halt it. Adrenomyeloneuropathy progresses slowly.

## Prevention

- Newborn screening where available, testing of relatives and genetic counselling of carriers.

## Test yourself

Think of the answer, then tap the question to see it.

## Which gene and protein fail in X-linked adrenoleukodystrophy?

ABCD1, which encodes ALDP, the peroxisomal transporter of very-long-chain acyl-CoAs.

## Which endocrine gland is typically affected?

The adrenal cortex: primary adrenal insufficiency.

## Which treatment can halt the early cerebral form?

Haematopoietic stem cell transplant (or gene therapy) before the damage advances.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/conditions/x-linked-adrenoleukodystrophy/)

## Related conditions

- [Adrenal insufficiency](https://durgical.com/en/conditions/adrenal-insufficiency/)
- [Zellweger syndrome (Zellweger spectrum)](https://durgical.com/en/conditions/zellweger-syndrome/)
- [Multiple sclerosis](https://durgical.com/en/conditions/multiple-sclerosis/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [X-linked adrenoleukodystrophy: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/x-linked-adrenoleukodystrophy/) (MedlinePlus, US National Library of Medicine, 2026); [ABCD1 gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/abcd1/) (MedlinePlus, US National Library of Medicine, 2026); [Beta-oxidation of very long chain fatty acids](https://reactome.org/PathwayBrowser/#/R-HSA-390247) (Reactome, 2026).

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Source: https://durgical.com/en/conditions/x-linked-adrenoleukodystrophy/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/x-linked-adrenoleukodystrophy/