Achondroplasia accounts for about 75% of all dwarfism; however, it is nonetheless a rare condition, affecting only 1 out of 50,000 live births. Most achondroplastic children will grow up in communities without any peers sharing the same diagnosis. The gene for achondroplasia is a single mutation on a growth factor gene. Achondroplasia is transmitted as a dominant gene. Still, most cases (80%) are spontaneous mutations, and these patients are born of normal stature parents. Hypochondroplasia is genetically similar to achondroplasia but is phenotypically a much milder form of dwarfism.
In addition to the obvious limb deformities of short stature and bowing, children with achondroplasia typically have frontal bossing (prominent forehead), midface hypoplasia (upper jaw, cheekbones, and eye sockets have not grown as much as the rest of the face), hyperlordosis of the spine, delayed developmental milestones, and spinal stenosis (narrowing of the open spaces within the spine). Achondroplastic dwarfism presents with a rhizomelic disproportion (when the upper limbs are short relative to the lower limbs), short stature, and characteristic limb deformities. The primary defect is in the growth plates of the lower and upper extremities.
The stature of achondroplastic dwarfs falls significantly below the growth charts for most children. The average adult height for achondroplastic men at skeletal maturity is 131 cm and for women is 125 cm. In comparison, the low end of height at skeletal maturity for men without achondroplasia is 160 cm and for women is 151 cm. Tall parental heights is associated with relatively taller height in achondroplastic children. The short stature of patients with achondroplasia is not simply due to growth at a different rate than children without achondroplasia; they have a completely different growth pattern. The height multipliers for achondroplastic children are completely different.
At the Paley Institute, we offer our patients and families a comprehensive analysis of the myriad current and predicted limb manifestations of achondroplasia. We formulate a personalized reconstructive plan to normalize limb and joint alignment combined with extensive limb lengthening (ELL) for stature and for restoration of proportion of the limbs to the trunk. Our goals are to correct deformities, correct body proportion, and achieve a functional height.
The Paley Institute has a decades-long track record of safe, reliable, accurate limb lengthening and reconstruction. We have treated more patients with achondroplasia than any other center in the world. Our team, facility, and infrastructure are designed to help patients achieve their desired results.