A newly identified mutation in the PEX26 gene is associated with a milder form of Zellweger spectrum disorder

Akemi J. Tanaka, Kanji Okumoto, Shigehiko Tamura, Yuichi Abe, Yoel Hirsch, Liyong Deng, Joseph Ekstein, Wendy K. Chung, Yukio Fujiki

Research output: Contribution to journalArticle

Abstract

Using clinical exome sequencing (ES), we identified an autosomal recessive missense variant, c.153C>A (p.F51L), in the peroxisome biogenesis factor 26 gene (PEX26) in a 19-yr-old female of Ashkenazi Jewish descent who was referred for moderate to severe hearing loss. The proband and three affected siblings are all homozygous for the c.153C>A variant. Skin fibroblasts from this patient show normal morphology in immu-nostaining of matrix proteins, although the level of catalase was elevated. Import rate of matrix proteins was significantly decreased in the patient-derived fibroblasts. Binding of Pex26-F51L to the AAA ATPase peroxins, Pex1 and Pex6, is severely impaired and affects peroxisome assembly. Moreover, Pex26 in the patient’s fibroblasts is reduced to ∼30% of the control, suggesting that Pex26-F51L is unstable in cells. In the patient’s fibroblasts, peroxisome-targeting signal 1 (PTS1) proteins, PTS2 protein 3-ketoacyl-CoA thiolase, and catalase are present in a punctate staining pattern at 37°C and in a diffuse pattern at 42°C, suggesting that these matrix proteins are not imported to peroxisomes in a temperature-sensitive manner. Analysis of peroxisomal metabolism in the patient’s fibroblasts showed that the level of docosahexaenoic acid (DHA) (C22:6n-3) in ether phospholipids is decreased, whereas other lipid metabolism, including peroxisomal fatty acid β-oxidation, is normal. Collectively, the functional data support the mild phenotype of nonsyndromic hearing loss in patients harboring the F51L variant in PEX26.

Original languageEnglish
Article numbera003483
JournalCold Spring Harbor Molecular Case Studies
Volume5
Issue number1
DOIs
Publication statusPublished - Jan 1 2019

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Medicine
  • Genetics
  • Genetics(clinical)

Cite this