CausesBy Mayo Clinic staff
Most dwarfism-related conditions are genetic disorders, but the causes of some disorders are unknown. Most occurrences of dwarfism result from a random genetic mutation in either the father's sperm or the mother's egg rather than being in either parent's complete genetic makeup.
About 80 percent of people with achondroplasia are born to parents of average height. A person with achondroplasia and with two average-size parents received one mutated copy of the gene associated with the disorder and one normal copy of the gene. A person with the disorder may pass along either a mutated or normal copy to his or her own children.
Turner syndrome occurs because of a random deletion or severe alteration of an X chromosome either in the sperm or egg. The X chromosome is one of two chromosomes that determine the sex of a person. A female inherits an X chromosome from each parent, and a male inherits a Y chromosome from his father and an X chromosome from his mother. A girl with Turner syndrome has only one fully functioning copy of the female sex chromosome rather than two.
Growth hormone deficiency
The cause of growth hormone deficiency can sometimes be traced to a genetic mutation or injury, but for most people with the disorder, no cause can be identified.
Other causes of dwarfism include deficiencies in other hormones and poor nutrition.
- Dwarfism: Frequently asked questions. Little People of America. http://www.lpaonline.org/mc/page.do?sitePageId=84634. Accessed July 3, 2011.
- Wright MJ, et al. Clinical management of achondroplasia. Archives of Diseases in Childhood. In press. Accessed July 3, 2011.
- Canale ST. Osteochondrosis or Epiphysitis and Other Miscellaneous Affections. In: Canale ST, et al. Campbell's Operative Orthopaedics. 11th ed. Philadelphia, Pa.:Mosby Elsevier; 2007. http://www.mdconsult.com/books/page.do?eid=4-u1.0-B978-0-323-03329-9..50032-5--cesec54&isbn=978-0-323-03329-9&sid=1176248236&uniqId=263706808-3#4-u1.0-B978-0-323-03329-9..50032-5--cesec59. Accessed July 3, 2011.
- Hypochondroplasia. Genetics Home Reference. http://ghr.nlm.nih.gov/condition=hypochondroplasia. Accessed July 3, 2011.
- Spondyloepiphyseal dysplasia congenita. Genetics Home Reference. http://ghr.nlm.nih.gov/condition=spondyloepiphysealdysplasiacongenita. Accessed July 3, 2011.
- Diastrophic dysplasia. Genetics Home Reference. http://ghr.nlm.nih.gov/condition=diastrophicdysplasia. Accessed July 3, 2011.
- Hypopituitarism in children resulting in short stature. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/print/sec13/ch161/ch161d.html. Accessed July 3, 2011.
- Learning about Turner syndrome. National Human Genome Research Institute. http://www.genome.gov/pfv.cfm?pageID=19519119. Accessed July 3, 2011.
- Achondroplasia. Genetics Home Reference. http://ghr.nlm.nih.gov/condition=achondroplasia. Accessed July 3, 2011.
- Richmond EJ. Diagnosis of growth hormone deficiency in children. http://www.uptodate.com/home/index.html. Accessed July 3, 2011.
- Horton WA, et al. Achondroplasia. The Lancet. 2007;370:162.