Peroxisome Biogenesis Disorder 2b

A number sign (#) is used with this entry because this form of peroxisome biogenesis disorder (PBD2B) is caused by homozygous mutation in the PEX5 gene (600414) on chromosome 12p13.3. Mutations in the PEX5 gene also cause Zellweger syndrome (PBD2A; 214110).

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 PEX5 gene have cells of complementation group 2 (CG2). For information on the history of PBD complementation groups, see 214100.

Molecular Genetics

Dodt et al. (1995) reported a homozygous mutation in the PEX5 gene in a cell line from a patient with NALD (600414.0001).