Hypochondroplasia
Last updated 29 May 2023
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Hypochondroplasia is a form of short-limbed dwarfism. This condition affects the conversion of cartilage into bone (a process called ossification), particularly in the long bones of the arms and legs. Hypochondroplasia is similar to another skeletal disorder called achondroplasia, but the features tend to be milder.
Description
Hypochondroplasia is a form of short-limbed dwarfism. This condition affects the conversion of cartilage into bone (a process called ossification), particularly in the long bones of the arms and legs. Hypochondroplasia is similar to another skeletal disorder called achondroplasia, but the features tend to be milder.
All people with hypochondroplasia have short stature. The adult height for men with this condition ranges from 138 centimeters to 165 centimeters (4 feet, 6 inches to 5 feet, 5 inches). The height range for adult women is 128 centimeters to 151 centimeters (4 feet, 2 inches to 4 feet, 11 inches).
People with hypochondroplasia have short arms and legs and broad, short hands and feet. Other characteristic features include a a large head (macrocephaly), limited range of motion at the elbows, a sway of the lower back (lordosis), and bowed legs. These signs are generally less pronounced than those seen in people with achondroplasia and may not be noticeable until early or middle childhood. Affected individuals have a small increased risk of a seizure disorder known as temporal lobe epilepsy. Some studies have reported that a small percentage of people with hypochondroplasia have mild to moderate intellectual disability or learning problems, but other studies have produced conflicting results.
Inheritance patterns
The source lists the following possible inheritance patterns: Autosomal dominant. More than one pattern can apply in different cases.
Related genes
Other names
HCH
Hypochondrodysplasia
Further reading and references
- Hypochondroplasia; MedlinePlus, National Library of Medicine.
- Bober MB, Bellus GA, Cheung MS, Jain M, Nikkel SM, Tiller GE. Hypochondroplasia. 1999 Jul 15 [updated 2025 Sep 25]. In: Adam MP, Bick S, Mirzaa GM, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2026. Available from http://www.ncbi.nlm.nih.gov/books/NBK1477/
- Cohen MM Jr. Some chondrodysplasias with short limbs: molecular perspectives. Am J Med Genet. 2002 Oct 15;112(3):304-13. doi: 10.1002/ajmg.10780.
- Foldynova-Trantirkova S, Wilcox WR, Krejci P. Sixteen years and counting: the current understanding of fibroblast growth factor receptor 3 (FGFR3) signaling in skeletal dysplasias. Hum Mutat. 2012 Jan;33(1):29-41. doi: 10.1002/humu.21636. Epub 2011 Nov 16.
- Horton WA, Lunstrum GP. Fibroblast growth factor receptor 3 mutations in achondroplasia and related forms of dwarfism. Rev Endocr Metab Disord. 2002 Dec;3(4):381-5. doi: 10.1023/a:1020914026829. No abstract available.
- Vajo Z, Francomano CA, Wilkin DJ. The molecular and genetic basis of fibroblast growth factor receptor 3 disorders: the achondroplasia family of skeletal dysplasias, Muenke craniosynostosis, and Crouzon syndrome with acanthosis nigricans. Endocr Rev. 2000 Feb;21(1):23-39. doi: 10.1210/edrv.21.1.0387.
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