HYPOCHONDROPLASIA:

Hypochondroplasia (HCH) is a disorder that resembles achondroplasia but is phenotypically less severe.  The classic features include rhizomelic shortening, megalocephaly, lumbar lordosis and other skeletal abnormalities.  Intelligence is unaffected.  Many cases of HCH are spontaneous; however, the remainder are inherited in an autosomal dominant manner.  In the inherited form, the disease is considered fully penetrant and on the average 50% of all children of the affected parent will have the disease.  A single mutation, (N540K) in the Fibroblast Growth Factor Receptor, Type 3 (FGFR3) gene, has been discovered to cause approximately  70% of HCH of both spontaneous and hereditary types.

• To confirm the nature of the dwarfism in an affected individual.
• To evaluate fetuses with unusually small stature by ultrasound for the possibility of spontaneous ACH.
• Individuals at risk who wish prenatal diagnosis.

• For ambiguous patients this test may be ordered as part of a Dwarfism Panel.

• Detection of a N540K mutation by PCR amplification followed by DNA sequencing or mutation specific restriction enzyme digestion.

• Blood EDTA (purple top) tubes:  

            Newborn: minimum 1-2 mL          

            Child/Adult: prefer 2 tubes of 3-5 mL

• Prenatal testing: Please contact the laboratory for instructions.

TURNAROUND TIME:     10 working days

CPT CODES: