| Domain | PEX13-specific finding | Evidence type | Key source/date |
|---|---|---|---|
| Identity and inheritance | Peroxisome biogenesis disorder 11B is **PEX13-related Zellweger spectrum disorder**, caused by biallelic germline **PEX13** variants and inherited in an autosomal-recessive manner. | Human genetic; PEX13-specific | Borgia et al., July 2022, [DOI](https://doi.org/10.1186/s13023-022-02415-5); Su et al., November 2024, [DOI](https://doi.org/10.1002/mgg3.2315) (pqac-00000000, pqac-00000002) |
| Reported case count | A 2024 review counted **22 reported patients worldwide** and approximately **20 variant types**, demonstrating extreme rarity. This is a literature case count, not a population-prevalence estimate. | Human literature review; PEX13-specific | Su et al., November 2024, [DOI](https://doi.org/10.1002/mgg3.2315) (pqac-00000003) |
| Representative variants | Reported alleles include **c.493G>C (p.Ala165Pro)**, **c.880C>T (p.Arg294Trp)**, **p.Trp313Gly**, **p.Trp313Ter**, **p.Gly324Arg**, truncating variants, and partial or large deletions. p.Arg294Trp recurred in three of five families in a 2022 series. | Human genetic plus functional or computational; PEX13-specific | Borgia et al., July 2022, [DOI](https://doi.org/10.1186/s13023-022-02415-5); Su et al., November 2024, [DOI](https://doi.org/10.1002/mgg3.2315) (pqac-00000001, pqac-00000003, pqac-00000005) |
| Core mechanism | PEX13 is a peroxisomal-membrane docking and translocation factor for PEX5/PEX14-mediated matrix-protein import. Pathogenic variants impair PEX13 self-association or partner binding, reducing PTS1 or PTS2 import and functional peroxisomes; secondary mitochondrial dysfunction may contribute. | Human cells, structural biology, computational modeling, and mouse experiments | Krause et al., October 2013, [DOI](https://doi.org/10.1093/hmg/ddt238); Borgia et al., July 2022, [DOI](https://doi.org/10.1186/s13023-022-02415-5) (pqac-00000017, pqac-00000019, pqac-00000020) |
| 2024 mechanistic advance | Structural work showed that the PEX13 SH3 domain and proximal **FxxxF** motif regulate binding to PEX5 WxxxF/Y motifs and PEX14. PEX14 bound the PEX13 FxxxF motif with a dissociation constant of **9.2 micromolar**. | In vitro biochemical and structural; PEX13-specific | Gaussmann et al., April 2024, [DOI](https://doi.org/10.1038/s41467-024-47605-w) (pqac-00000023, pqac-00000024, pqac-00000025) |
| Phenotype | PEX13-related disease ranges from severe neonatal multisystem illness to childhood progressive neurologic disease. Findings include hypotonia, seizures, developmental delay or regression, spasticity, leukodystrophy, hearing or vision impairment, feeding or respiratory difficulty, and hepatic or renal involvement. Frequencies cannot be estimated reliably from the small reported population. | Human clinical; PEX13-specific | Borgia et al., July 2022, [DOI](https://doi.org/10.1186/s13023-022-02415-5); Su et al., November 2024, [DOI](https://doi.org/10.1002/mgg3.2315) (pqac-00000001, pqac-00000004, pqac-00000006) |
| Diagnostics | Diagnosis combines plasma very-long-chain fatty acids, especially C26:0 and the C26:0/C22:0 ratio, with phytanic and pristanic acids, pipecolic acid, bile-acid intermediates, plasmalogens, and molecular confirmation by a PEX panel or exome or genome sequencing. Normal or mildly abnormal VLCFA does **not** exclude PEX13 disease. | PEX13 cases plus ZSD-wide diagnostic evidence | Borgia et al., July 2022, [DOI](https://doi.org/10.1186/s13023-022-02415-5); Bose et al., June 2022, [DOI](https://doi.org/10.3390/cells11121891); Su et al., November 2024, [DOI](https://doi.org/10.1002/mgg3.2315) (pqac-00000004, pqac-00000011, pqac-00000022) |
| Prognosis | PEX13-specific prognosis is genotype-dependent and incompletely quantified. Severe homozygous disease can cause early death; the 2024 p.Ala165Pro case died at **14 months**. Hypomorphic genotypes may permit survival into later childhood with progressive disability. ZSD-wide survival estimates are not PEX13-specific. | Human case reports with ZSD-wide contextual evidence | Su et al., November 2024, [DOI](https://doi.org/10.1002/mgg3.2315); Bose et al., June 2022, [DOI](https://doi.org/10.3390/cells11121891) (pqac-00000004, pqac-00000007, pqac-00000013) |
| Treatment and trials | No curative or established PEX13-specific disease-modifying therapy exists. Care is supportive and may include antiseizure treatment, feeding support, hearing and vision services, rehabilitation, liver and adrenal surveillance, and respiratory care. Current ZSD studies are not PEX13-specific; recruiting **NCT06190626** follows retinopathy in 30 participants, while evidence for cholic acid, betaine, and hydroxychloroquine remains limited or conflicting. | Clinical management and ZSD-wide trials; not PEX13-specific | ClinicalTrials.gov, 2023, [NCT06190626](https://clinicaltrials.gov/study/NCT06190626); Bose et al., June 2022, [DOI](https://doi.org/10.3390/cells11121891) (pqac-00000009, pqac-00000012) |


*Table: Compact evidence summary for PEX13-related peroxisome biogenesis disorder 11B. It distinguishes disease-specific observations from broader Zellweger spectrum disorder evidence and highlights recent mechanistic and clinical developments.*