HSD17B4 encodes hydroxysteroid 17-beta dehydrogenase 4 (736 aa). Bifunctional enzyme acting on the peroxisomal fatty acid beta-oxidation pathway. Highest expression in Thyroid (203.8 TPM) and Adrenal Gland (129.8 TPM).

D-bifunctional protein deficiency is caused by mutations in the HSD17B4 gene on chromosome 5.

The HSD17B4 protein participates in HSD17B4 dehydrogenates 3-hydroxyhexacosanoyl-CoA, HSD17B4 hydrates trans-2,3-dehydrohexacosanoyl-CoA, and Hydration of delta2-tetracosaheptaenoyl-CoA to 3-hydroxy tetracosahexaenoyl-CoA pathways.

HSD17B4 is classified as a druggable target (Druggable Genome, Enzyme, and Short Chain Dehydrogenase Reductase categories) with score 0.0.

Genetic testing for HSD17B4 is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 7 always present features, 3 very common features, 30 common features.

2 clinical trials registered, 1 recruiting. Interventions under study include drug therapy, other interventions, and biologic therapy. Pipeline includes 1 PHASE2. Research is primarily sponsored by academic and government institutions.

23 publications have been identified in PubMed for d-bifunctional protein deficiency. Research spans Case Report / Case Series (48%), Basic Science / Preclinical (35%), and Review / Meta-Analysis (13%).

Recent Publications

• Wang J (2026). [PMID: 42219416](https://pubmed.ncbi.nlm.nih.gov/42219416/). *Cell Mol Life Sci*. [Basic Science / Preclinical]

• Erdal AE (2026). [PMID: 40416444](https://pubmed.ncbi.nlm.nih.gov/40416444/). *Molecular syndromology*. [Case Report / Case Series]

• Wang W (2026). [PMID: 41765062](https://pubmed.ncbi.nlm.nih.gov/41765062/). *Mitochondrion*. [Basic Science / Preclinical]

• Shokouhian E (2026). [PMID: 39847269](https://pubmed.ncbi.nlm.nih.gov/39847269/). *J Appl Genet*. [Review / Meta-Analysis]

• Diaz-Moreno U (2026). [PMID: 41367148](https://pubmed.ncbi.nlm.nih.gov/41367148/). *Journal of inherited metabolic disease*. [Case Report / Case Series]

• Ahmad N (2026). [PMID: 41525964](https://pubmed.ncbi.nlm.nih.gov/41525964/). *Clinica chimica acta; international journal of clinical chemistry*. [Case Report / Case Series]

• Liu H (2025). [PMID: 41282484](https://pubmed.ncbi.nlm.nih.gov/41282484/). *Frontiers in genetics*. [Case Report / Case Series]

• Thomas HB (2025). [PMID: 40043708](https://pubmed.ncbi.nlm.nih.gov/40043708/). *American journal of human genetics*. [Basic Science / Preclinical]

• Bae JE (2025). [PMID: 40102401](https://pubmed.ncbi.nlm.nih.gov/40102401/). *Nature communications*. [Basic Science / Preclinical]

• Long X (2025). [PMID: 40410890](https://pubmed.ncbi.nlm.nih.gov/40410890/). *Human genomics*. [Review / Meta-Analysis]