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 (PBDs). The clinical course of patients with the NALD and IRD presentation ... 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 (PBDs). 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 PEX6 gene have cells of complementation group 4 (CG4, equivalent to CG6 and CGC). For information on the history of PBD complementation groups, see 214100.
Najmabadi et al. (2011) studied 5 sibs with moderate intellectual disability, retinitis pigmentosa, hearing loss, and ataxia. Their parents, who were second cousins, had 6 healthy children.
Matsumoto et al. (2001) found compound heterozygosity for mutations in the PEX6 gene (601498.0007, 601498.0008) in a patient with a diagnosis of neonatal adrenoleukodystrophy (NALD) of PBD complementation group 6.
The 5 sibs in the study ... Matsumoto et al. (2001) found compound heterozygosity for mutations in the PEX6 gene (601498.0007, 601498.0008) in a patient with a diagnosis of neonatal adrenoleukodystrophy (NALD) of PBD complementation group 6. The 5 sibs in the study of Najmabadi et al. (2011) carried a homozygous frameshift mutation in the PEX6 gene (601498.0009).