Achondroplasia is a hereditary, congenital autosomal dominant disorder that produces abnormalities in the growth and/or remodeling of cartilage and bone affecting the skull, spine, and extremities. The disorder, commonly known as dwarfism, frequently causes a person to be disproportionately short.

The recent estimate for the incidence of achondroplasia in the United States is approximately 1:29,000; internationally, the estimate is approximately 1:40,000.

Achondroplasia is an autosomal dominant inherited trait. The defect occurs on the short arm of chromosome 4—specifically, band 4p16.3.