Overview
Achondroplasia is an autosomal dominant condition resulting in disproportionate short stature (‘dwarfism’). It occurs due to a mutation in the fibroblast growth factor receptor 3 (FGFR3) gene, which is involved in the development of bone from cartilage.
Inheriting two copies of the affected gene is incompatible with life.
Epidemiology
- Achondroplasia has a prevalence of up to 1 in 20,000 live births
- Although achondroplasia is autosomal dominant, most cases occur sporadically
- Increasing paternal age is a risk factor
Presentation
- Large skull, normal trunk length, but short arms and legs (rhizomelia)
- Trident-like hands with short fingers (brachydactyly)
- Marked lumbar lordosis
- Forehead frontal bossing and a flat nasal bridge
Prognosis
- In most cases, life expectancy is normal
- The average adult height is around 4 feet (~120 cm)
