Hypochondroplasia: A type of short-limb dwarfism, with shortening especially of the ends of the limbs. A child with hypochondroplasia usually has a prominent forehead, mildly shortened extremities and digits, limited range of motion at the elbows, and inward curvature of the lower back. Diagnosis is made through physical examination and X-rays. Hypochondroplasia is inherited in an autosomal dominant manner. Hypochondroplasia can also occur spontaneously. The gene for hypochondroplasia is the same gene that causes achondroplastic dwarfism: the fibroblast growth factor receptor 3 (FGFR3). However, the two forms of dwarfism are caused by different mutations in FGFR3.