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Early hypotonia and visual regression as presenting features of peroxisome biogenesis disorder: an Egyptian case

Abdelrahim A Sadek1, Mohammed A Aladawy2, Khaled Hassan2

  • 1Neuropsychiatry Unit, Department of Pediatrics, Faculty of Medicine, Sohag University, Sohag, Egypt.

BMC Pediatrics
|May 19, 2026
PubMed

Insights

This case study details a rare Egyptian PEX12 peroxisome biogenesis disorder (PBD) in a child with previously unreported optic atrophy. Early diagnosis via whole-exome sequencing is crucial for managing this neurodegenerative condition.

Area of Science:

  • Genetics and Molecular Biology
  • Neuroscience
  • Rare Diseases

Background:

  • Peroxisome biogenesis disorders (PBDs) are rare genetic conditions causing neurodegeneration.
  • A specific PEX12 variant is prevalent in Egyptian populations, suggesting a founder effect.
  • The clinical spectrum of PEX12-related PBD is not fully defined.

Purpose of the Study:

  • To report the first Egyptian case of PEX12-related PBD with optic atrophy.
  • To expand the known clinical phenotype of this PEX12 variant.
  • To highlight the utility of whole-exome sequencing in diagnosing PBDs.

Main Methods:

  • Case presentation of a six-year-old Egyptian boy with neurodevelopmental regression.
  • Ophthalmologic, audiologic, and brain MRI assessments.
  • Trio whole-exome sequencing to identify the genetic cause (homozygous PEX12 deletion c.1047_1049del).

Main Results:

  • The patient presented with hypotonia, developmental regression, bilateral optic atrophy, and sensorineural hearing loss.
  • Brain MRI revealed white matter abnormalities and corpus callosum involvement.
  • Whole-exome sequencing confirmed a homozygous PEX12 deletion, diagnosing a Zellweger spectrum disorder.

Conclusions:

  • This case expands the PEX12-related PBD phenotype to include optic atrophy.
  • Whole-exome sequencing is valuable for diagnosing PBDs, especially when biochemical tests are inconclusive.
  • Increased awareness of founder variants in consanguineous populations aids early diagnosis and screening.
Abstract

Keywords:
PEX12 geneConsanguinityDevelopmental regressionEgyptOptic atrophyPeroxisome biogenesis disorderVariantWhole-exome sequencingZellweger spectrum disorder

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