Features include always present findings: Mesomelia, Rhizomelia, Barrel-shaped chest, and Joint hypermobility and others; and very common findings: Abnormal nail morphology. 24 total HPO annotations.

ACAN encodes aggrecan (2,530 aa). This proteoglycan is a major component of extracellular matrix of cartilagenous tissues. A major function of this protein is to resist compression in cartilage. Highest expression in Artery Tibial (34.4 TPM) and Artery Aorta (21.7 TPM).

Spondyloepimetaphyseal dysplasia, aggrecan type is associated with mutations in the ACAN gene on chromosome 15.

ACAN is classified as a druggable target (Druggable Genome category) with score 0.0.

74 pathogenic variants reported in ACAN in ClinVar.

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

Phenotype severity distribution: 14 always present features, 1 very common feature, 2 common features.

Estimated prevalence: <1 in 1,000,000 (VERY_RARE).