Peroxisomal Acyl-CoA Oxidase Deficiency

Straight-Chain Acyl-CoA Oxidase Deficiency; Pseudoneonatal Adrenoleukodystrophy


Autosomal recessive

Inheritance from both parents will result in the disease

Age range at onset:


Specialists you may see:


Seizures and hypotonia are common in newborns with this deficiency. They may  also have distinctive facial features such as hypertelorism, low-set ears and a low nasal bridge. Some may also have hepatomegaly and polydactyly. Strabismus, nystagmus and optic atrophy can also occur.

Infants with this condition usually learn to walk and begin to talk before experiencing regression and losing these skills between the ages of 1 and 3. As the condition worsens, those affected experience hyperreflexia, severe and recurrent seizures and vision and hearing loss. Most do not survive past early childhood.


Mutations in the ACOX1 gene cause this deficiency. The ACOX1 gene creates an enzyme called peroxisomal straight-chain Acyl-CoA oxidase, which plays a role in the break down of Very Long Chain Fatty Acids, or VLCFAs. When the ACOX1 gene is mutated, these VLCFAs cannot be broken down easily, and accumulate. It is not clear how this accumulation leads to the above symptoms.

High levels of VLCFAs can also be an indicator of Adrenoleukodystrophy, hence the alternative name of this condition, pseudoneonatal adrenoleukodystrophy.

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