Features include always present findings: Split hand; and very common findings: Inner ear hearing loss (sensorineural hearing impairment) and Split foot. 6 total HPO annotations.

MAP3K20 encodes mitogen-activated protein kinase kinase kinase 20 (800 aa). Stress-activated component of a protein kinase signal transduction cascade that promotes programmed cell death in response to various stress, such as ribosomal stress, osmotic shock and ionizing radiation. Highest expression in Esophagus Muscularis (113.8 TPM) and Muscle Skeletal (111.2 TPM).

Split-foot malformation-mesoaxial polydactyly syndrome is associated with mutations in the MAP3K20 gene on chromosome 2.

MAP3K20 is classified as a druggable target (Druggable Genome, Enzyme, Kinase, and Serine Threonine Kinase categories) with score 2.2.

Genetic testing for MAP3K20 is available. Testing is considered confirmatory for diagnosis.

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

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