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hyperekplexia 4 (HKPX4) - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

hyperekplexia 4

MONDO:0044330

Also known as:HKPX4

Overview

Hyperekplexia-4 is an autosomal recessive severe neurologic disorder apparent at birth. Affected infants have extreme hypertonia and appear stiff and rigid. They have little if any development, poor or absent visual contact, and no spontaneous movement, consistent with an encephalopathy. Some patients have early-onset refractory seizures, and many have inguinal or umbilical hernia. Most patients die in the first months of life due to respiratory failure or other complications (summary by {2:Piard et al., 2018}).nnFor a general description and a discussion of genetic heterogeneity of hyperekplexia, see HKPX1 (OMIM:149400).

GeneticsAutosomal recessive · ATAD1 (chr 10)

ResearchLimited published research (7 articles)

Clinical Presentation

Built from Human Phenotype Ontology (HPO) phenotype annotations and GeneReviews clinical descriptions. Features represent findings documented across known cases — not an exhaustive list of possible symptoms.

Features include always present findings: Hypertonia, Inguinal hernia, Seizure, and Respiratory failure; and common findings: Hypsarrhythmia and Overactive reflexes (hyperreflexia). 20 total HPO annotations.

Organ System	Phenotype Count	Example Features
Brain and nerves	6	Encephalopathy, Brain shrinkage (cerebral atrophy), Seizure

Genetic Landscape

Assembled from HGNC gene records, ClinGen gene-disease validity evidence, and ClinVar pathogenic variant data. Validity classifications reflect the strength of published evidence linking each gene to this disease.

ATAD1 encodes ATPase family AAA domain containing 1 (361 aa). Outer mitochondrial translocase required to remove mislocalized tail-anchored transmembrane proteins on mitochondria. Highest expression in Testis (55.9 TPM) and Cells EBV-transformed lymphocytes (46.8 TPM).

Hyperekplexia 4 is associated with mutations in the ATAD1 gene on chromosome 10.

ATAD1 is classified as a druggable target with score 0.0.

Diagnosis

Genetic testing for ATAD1 is available. Testing is considered confirmatory for diagnosis.

Prognosis

Phenotype severity distribution: 4 always present features, 2 common features.

Research Landscape

Sourced from ClinicalTrials.gov and PubMed. Publication types are classified using NLM-curated article metadata; research type breakdowns reflect the nature of published work for this disease.

No clinical trials have been registered for hyperekplexia 4.

7 publications have been identified in PubMed for hyperekplexia 4. Research spans Case Report / Case Series (57%), Review / Meta-Analysis (29%), and Basic Science / Preclinical (14%).

Recent Publications

Lin SZ (2026). [PMID: 41578547](https://pubmed.ncbi.nlm.nih.gov/41578547/). *Medicine*. [Case Report / Case Series]
Sarigecili E (2026). [PMID: 42013565](https://pubmed.ncbi.nlm.nih.gov/42013565/). *Pediatr Neurol*. [Review / Meta-Analysis]
Li EC (2025). [PMID: 39693598](https://pubmed.ncbi.nlm.nih.gov/39693598/). *Neurology(R) neuroimmunology & neuroinflammation*. [Review / Meta-Analysis]
Kollia E (2025). [PMID: 40068485](https://pubmed.ncbi.nlm.nih.gov/40068485/). *European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society*. [Case Report / Case Series]
Yılmaz FH (2025). [PMID: 41064056](https://pubmed.ncbi.nlm.nih.gov/41064056/). *Molecular syndromology*. [Case Report / Case Series]

Data assembled from 5 of 12 sources · Last updated Sep 19, 2026, 12:58 PM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:618011

GARD

Genetic and Rare Diseases Info Center

GARD:16284

Questions for Your Care Team

→Should my partner and I meet with a genetic counselor to discuss carrier status and family planning?
→Are there specialists or centers of excellence for this condition in my area?
→Is there a patient registry I should consider joining?

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hyperekplexia 4

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Prognosis

Research Landscape

Recent Publications

Medical References

External Resources

OMIM

GARD

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Questions for Your Care Team

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