ICD10 code of Hypochondroplasia and ICD9 code

Hypochondroplasia is classified under the ICD-10-CM code Q77.4, which specifically denotes achondroplasia and hypochondroplasia. In the older ICD-9-CM classification system, the condition was identified by the code 756.4.

What is the clinical significance of Hypochondroplasia?

Hypochondroplasia is a form of short-limbed dwarfism characterized by a milder clinical phenotype compared to achondroplasia. While Hypochondroplasia is often diagnosed later in childhood due to its subtle presentation, individuals typically experience disproportionate short stature, lumbar lordosis, and sometimes mild intellectual disability or learning difficulties. At DiseaseMaps.org, 22 members have connected to share their experiences with Hypochondroplasia, highlighting the importance of community support for this rare condition.

How is Hypochondroplasia diagnosed?

Diagnosis of Hypochondroplasia is confirmed through a combination of clinical assessment, radiographic skeletal surveys, and molecular genetic testing. Most cases of Hypochondroplasia are caused by mutations in the FGFR3 gene. Clinicians look for specific skeletal markers to differentiate it from other skeletal dysplasias.

What are the key diagnostic features of Hypochondroplasia?

• Mild to moderate short stature with rhizomelic (proximal) shortening of limbs.


• Characteristic radiographic findings such as elongated femoral necks and mild lumbar vertebral changes.


• Molecular confirmation of an FGFR3 mutation, typically identified in approximately 70% of clinical cases.


• A generally normal-appearing skull, which helps distinguish Hypochondroplasia from more severe forms of dwarfism.

Is Hypochondroplasia hereditary?

Yes, Hypochondroplasia follows an autosomal dominant inheritance pattern. This means that an affected individual has a 50% chance of passing the condition to each offspring. However, many cases of Hypochondroplasia occur as a result of a *de novo* (new) mutation in the affected individual, meaning there is no family history of the condition.

Next steps

• Consult with a clinical geneticist to discuss inheritance risks and diagnostic testing.


• Seek evaluation from a pediatric endocrinologist to monitor growth and manage potential orthopedic complications.


• Connect with the 22 members currently on DiseaseMaps.org who share your experience with Hypochondroplasia.


• Review the latest research on FGFR3-related disorders via the NIH GARD portal.

Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Hypochondroplasia.


• Orphanet: Hypochondroplasia (ORPHA:408).


• OMIM (Online Mendelian Inheritance in Man): Hypochondroplasia (#146000).


• Little People of America (LPA): Medical resources for skeletal dysplasias.