Hypochondroplasia

Last Modified: 11/5/2014 12:27:57 PM


Client Notes: Please contact the laboratory at 266-1500 (Option 1) if this is prenatal testing or for payment requirements of this test
Specimen Requirements:

3.0 mL Whole Blood in a Lavender Top Tube - EDTA 

Pediatric requirements: 1.0 to 2.0 mL Whole Blood in a Lavender Top Tube - EDTA
Minimum Volume: 1.0 mL
Transport & Storage: Temperature/Stability: 48 to 72 hours Ambient
Reference Range: Refer to Interpretive Results
Test Comments: Detection of a N540K mutation by PCR amplification followed by DNA sequencing or mutation specific restriction enzyme digestion
Methodology: PCR amplification
Clinical Significance: 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. 

REASONS FOR REFERRAL: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.
Custom Panel: No

PRODUCTION SCHEDULE

Turn Around Time: 10 days
Other Testing Facility: Saint Francis
PHL Test Code: HCPX
EPIC Test Code:
Alternate Test Names: HCH
CPT Coding: 83890, 83894, 83898, 83904, 83912

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