This is the genetic variation that produces small bodied people whose
bodies differ in proportion to large bodied individuals. The main feature is
disproportionate shortening of arms and legs.
There are other causes of short stature which are not principally genetic in origin - i.e. do not relate to the FGFR3 site on Human Chromosome 4.
A single gene variation produces this condition.
In 1994 Dr. John Wasmuth and his colleagues found that a variation in the fibroblast growth factor receptor-3 (FGFR3) on Human Chromosome 4 causes achondroplasia. (ref. Human Growth Foundation documentation)
85% of occurrences are by a spontaneous mutation of genetic material. It is inherited as a dominant transferable characteristic, and requires a variant gene from only one parent (heterozygous dominant?).
Other sources of information.
The Achondroplasia UK has excellent pages of information on Achondroplasia; some are in layman's language others are very detailed (updated 2007).
Genetics Home Reference has good documentation of this condition. It is
detailed information in accessible language; this page is a good starting point.
For genetic information try looking up FGFR3 on Human Chromosome 4
The Human Growth Foundation has some information of growth disorders, and a brief section on Anchondroplasia specifically.
This is a page from
www.genefaith.org created by A. J. Palmer.
This page was updated on 18th August 2011.