Achondroplasia and Hypochondroplasia
Introduction
Achondroplasia (ACH) is the most common form of disproportionate short stature in adults and children with an estamated prevalance of 1:27,000. Hypochondroplasia (HCH) with prevalence of approximately 1: 33, 000) closely resembles achondroplasia but with milder clinical presentation (less pronounced short stature and skeletal disproportion compared to achondroplasia). Both conditions can be distinguished on clinical and radiographic grounds. Both are autosomal dominant disorders most commonly caused by sporadic mutations in the Fibroblast growth factor receptor 3 (FGFR3) gene located on chromosome 4 at 4p16.3.
Referral information
Molecular confirmation of a clinical diagnosis or preceding a potential prenatal diagnosis where one or both parents have either condition. Prenatal diagnosis is also offered following skeletal indications of achondroplasia/hypochondroplasia on antenatal ultrasound scanning.
Price & reporting times
NHS referrals to this service are paid for where there is an existing specialist commissioning contract for genetic testing. In other cases please contact the lab for prices.
| Test for Achondroplasia | NHS Price (£ ) | Non NHS Price (£) | TRT |
| Mutation screening | POA | POA | 28 cd |
| Prenatal diagnosis | POA | POA | 3 cd |
| Single mutation test | POA | POA | 28 cd |
| Test for Hypochondroplasia | NHS Price (£ ) | Non NHS Price (£) | TRT |
| Mutation screening | POA | POA | 56 cd |
| Prenatal diagnosis | POA | POA | 3 cd |
| Single mutation test | POA | POA | 28 cd |
Test validation & quality assurance - information for users
More than 98% of achondroplasia cases are due to a mutation p.Gly380Arg caused by one of two substitutions (c.1138G>A or G>C) in FGFR3 exon 10. Approximately 60-70% of hypochondroplasia cases are due to p.Asn540Lys caused by either c.1620C>A or C>G in exon 13 of FGFR3 and rare mutations have also been identified in exons 3, 5, 7 and 10 of FGFR3.
Sample requirements
4ml EDTA blood sample
Referral guidelines
Please see our referral guidelines for more information.
OMIM Number(s) - 100800 (Achondroplasia) and 146000 (Hypochondroplasia)
Gene(s) - Fibroblast Growth Factor Receptor 3 (FGFR3)