Unidentified woman, American Civil war, Photographer unknown
Achondroplasia, the most common form of dwarfism, accounts for approximately half of all known cases of profound short stature. Achondroplastic dwarfism is characterized by an average-size trunk, short arms and legs, and a slightly enlarged head and prominent forehead. Most achondroplastic dwarfs are born to average-size parents, and account for somewhere between one in 26,000 and one in 40,000 births. Adults, on average, are four feet tall.
Little People of America Online - Resources
The three most common causes of profound short stature are:
1.Achondroplasia (one per 14,000 births).
2.SED (one per 95,000 births).
3.Diastrophic dysplasia (one per 110,000 births).