Twins with PEX7 related intellectual disability and cataract: Highlighting phenotypes of peroxisome biogenesis...

Area of Science:

• Genetics
• Biochemistry
• Developmental Biology

Background:

• Peroxisome biogenesis disorders (PBDs) are inherited conditions affecting peroxisome formation.
• Mutations in the PEX gene family cause PBDs, leading to diverse clinical presentations.
• PEX7 gene mutations are associated with distinct PBD subtypes, including rhizomelic chondrodysplasia punctata type 1 (RCDP1) and PBD 9B.

Observation:

• This case report details a PEX7-related phenotype presenting in childhood.
• The observed phenotype included neurodevelopmental abnormalities and congenital cataracts, without the typical rhizomelia or chondrodysplasia seen in RCDP1.
• The patient's presentation mimicked aspects of classic Refsum disease in its variability.

Findings:

• PEX7 mutations can manifest in phenotypes beyond RCDP1 and adult-onset Refsum disease-like conditions.
• PBD 9B, an allelic disorder of PEX7, presents with a broader spectrum of symptoms than previously recognized.
• Congenital cataracts and neurodevelopmental issues in childhood are significant indicators of potential PEX7-related PBDs.

Implications:

• Recognizing the phenotypic variability of PEX7 mutations is crucial for accurate diagnosis.
• PBD 9B should be considered in the differential diagnosis of children with neurodevelopmental abnormalities and congenital cataracts.
• Further research into PEX7 genotype-phenotype correlations can improve understanding and management of these rare disorders.