Peroxisome Biogenesis Disorder 7b

A number sign (#) is used with this entry because this form of peroxisome biogenesis disorder (PBD7B) is caused by homozygous or compound heterozygous mutation in the PEX26 gene (608666) on chromosome 22q11.21. Mutation in PEX26 also causes Zellweger syndrome (PBD7A; 614872).

Description

The overlapping phenotypes of neonatal adrenoleukodystrophy (NALD) and infantile Refsum disease (IRD) represent the milder manifestations of the Zellweger syndrome spectrum (ZSS) of peroxisome biogenesis disorders. The clinical course of patients with the NALD and IRD presentation is variable and may include developmental delay, hypotonia, liver dysfunction, sensorineural hearing loss, retinal dystrophy, and visual impairment. Children with the NALD presentation may reach their teens, and those with the IRD presentation may reach adulthood (summary by Waterham and Ebberink, 2012).

For a complete phenotypic description and a discussion of genetic heterogeneity of PBD(NALD/IRD), see 601539.

Individuals with mutations in the PEX26 gene have cells of complementation group 8 (CG8, equivalent to CGA). For information on the history of PBD complementation groups, see 214100.

Molecular Genetics

Matsumoto et al. (2003) identified homozygosity for a missense mutation (608666.0001) in a patient with neonatal adrenoleukodystrophy (NALD).

Matsumoto et al. (2003) identified mutations in the PEX26 gene in patients with NALD (608666.0001) and infantile Refsum disease (IRD) (608666.0005-608666.0007).