When bigger isn’t always better
Dwarfism is rare, but not that rare. Is it something to be treated or just part of life’s rich tapestry?
Human height follows a normal distribution, typical of a trait influenced by many genes. At the extremes, though, the effects of single genes are seen in the genetic conditions of dwarfism and giganticism.
The term dwarfism applies to people with an adult height of 4'10" (147 cm) or less. There are about 200 types of dwarfism. The most common form (accounting for around 70 per cent of all cases) is achondroplasia, which occurs once in every 26,000–40,000 births. People with achondroplasia have disproportionately short arms and legs, and large heads with prominent foreheads.
Achondroplasia is caused by variations in the gene for fibroblast growth factor receptor 3 (FGFR3), which lead to abnormal bone development. Most cases (75–90 per cent) arise spontaneously, without any family history.
Although such conditions are associated with medical complications, people with achondroplasia can expect to live long and fulfilling lives. While certain routine activities, such as driving or turning lights on and off, may present problems, social attitudes often present a greater barrier to normal life. (See our two Real Voices interviews below for more.)