Features include always present findings: Decreased activity of mitochondrial complex I; and common findings: Encephalopathy, Generalized hypotonia, Thickened heart muscle (hypertrophic cardiomyopathy), and Congestive heart failure and others. 36 total HPO annotations.

ACAD9 encodes acyl-CoA dehydrogenase family member 9 (621 aa). Together with NDUFAF1 and ECSIT, forms part of the mitochondrial complex I (MCIA),which is required for the biogenesis of respiratory Complex I (CI) and is therefore crucial for the activation of the oxidative phosphorylation system. Highest expression in Skin Not Sun Exposed Suprapubic (77.7 TPM) and Skin Sun Exposed Lower leg (65.6 TPM).

Acyl-CoA dehydrogenase 9 deficiency is caused by mutations in the ACAD9 gene on chromosome 3.

ACAD9 is classified as a druggable target with score 0.0.

135 pathogenic variants reported in ACAD9 in ClinVar, including hotspot variants NP_054768.2:p.Arg266Trp (2-star review) and NP_054768.2:p.Arg518Cys (2-star review).

Genetic testing for ACAD9 is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 1 always present feature, 22 common features.

Estimated prevalence: Unknown (Unknown prevalence).

No clinical trials have been registered for acyl-CoA dehydrogenase 9 deficiency.

5 publications have been identified in PubMed for acyl-CoA dehydrogenase 9 deficiency. Research spans Basic Science / Preclinical (60%), Review / Meta-Analysis (20%), and Case Report / Case Series (20%).

Recent Publications

• Wang M (2026). [PMID: 41888097](https://pubmed.ncbi.nlm.nih.gov/41888097/). *Cell Death Dis*. [Basic Science / Preclinical]

• Jian J (2026). [PMID: 41861636](https://pubmed.ncbi.nlm.nih.gov/41861636/). *Ecotoxicol Environ Saf*. [Basic Science / Preclinical]

• Giguet-Valard AG (2025). [PMID: 40806260](https://pubmed.ncbi.nlm.nih.gov/40806260/). *International journal of molecular sciences*. [Case Report / Case Series]

• Li J (2025). [PMID: 40618880](https://pubmed.ncbi.nlm.nih.gov/40618880/). *Cancer letters*. [Basic Science / Preclinical]

• Häberle J (2024). [PMID: 38837457](https://pubmed.ncbi.nlm.nih.gov/38837457/). *Journal of inherited metabolic disease*. [Review / Meta-Analysis]