Symptoms of Hypochondroplasia
Hypochondroplasia is primarily characterized by small stature, disproportionately short arms and legs (limbs), mild to moderate shortness of the fingers and toes (brachydactyly), and broad, short hands and feet (i.e., short-limbed dwarfism). Slow growth often is not apparent at birth; as noted above, it may not be recognized until about two to three years of age, later during childhood, or as late as adulthood.

In those with hypochondroplasia, shortening of the limbs may be relatively mild or moderate. During early childhood, outward bowing of the legs (i.e., bowlegs [genu varum]) typically appears that is pronounced during weight bearing. This condition often improves spontaneously later during childhood. Many affected individuals also have limited extension and rotation of the elbows. In addition, beginning in childhood, exercise may result in minor aching or discomfort of the elbows, knees, and/or ankles. In affected adults, such joint pain may extend to involve the lower back. Approximately one third may also have abnormally pronounced inward curvature of the spine of the lower back (lordosis).

Some individuals with hypochondroplasia also have an abnormally large head (macrocephaly). In addition, the skull may be relatively broad and short (brachycephaly) or rectangular in shape with a slightly prominent forehead. However, the facial appearance is typically normal. Reports indicate that mild mental retardation may also be present in approximately 10 percent of affected individuals.