Fibroblast Growth Factor Receptor 3 (FGFR3)-related Skeletal Dysplasias
| Disorders | Thanatophoric dysplasia, Types I and II Achondroplasia Hypochondroplasia Non-syndromic craniosynostosis (NSC) |
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| Gene Name | FGFR3 | |
| Clinical info | Thanatophoric dysplasia, types I and II both display micromelia, short ribs, small thorax and are usually lethal. Type I will display bowed femurs while type II will display straight femurs and a clover-leaf skull. Achondroplasia patients will have short stature with disproportionately short limbs, frontal bossing and midface hypoplasia Hypochondroplasia also causes short stature with disproportionately short limbs, short hands and feet and macrocephaly. It is similar in phenotype to achondroplasia, though milder. |
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| Special Instructions | FGFR3 testing is not offered as a panel. You must specify which condition is clinically suspected. Testing for each condition must be ordered individually and will be billed separately. If you request more than one test, please specify the order in which they should be run or if they should be run simultaneously. | |
| Indications | Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutation within a family to allow for prenatal diagnosis. | |
| Detection | FGFR3 mutations will be identified in 99% of patients with thanatophoric dysplasia, types I and II, as well as achondroplasia. Approximately 70% of individuals with hypochondroplasia will have an identified FGFR3 mutation. | |
| Associated Tests | The FGFR3 gene is also included in the Next Generation Sequencing Skeletal Dysplasia Panel. | |
| Specimen Requirements | 5 to 10 ml of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred. The minimal blood needed for reliable DNA isolation is 3 ml | |
| Transport | The specimen should be kept at room temperature and delivered via overnight shipping. FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery. | |
| Turnaround time | 2 weeks | |
| Prenatal testing | Prenatal diagnosis is available if the familial mutation is known. Prenatal diagnosis can also be requested when there are ultrasound findings suggestive of an FGFR3-related disorder. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen. | |
| CPT Codes | Thanatophoric dysplasia, Type I - 81404 Thanatophoric dysplasia, Type II - 81403 Achondroplasia - 81404 Hypochondroplasia - 81404 Non-syndromic craniosynostosis - 81400 |
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| Cost | Thanatophoric dysplasia, Type I - $500 Thanatophoric dysplasia, Type II - $300 Achondroplasia – $300 Hypochondroplasia - $300 Non-syndromic craniosynostosis - $300 |
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| Contact | For further information contact This email address is being protected from spambots. You need JavaScript enabled to view it. , MS, Lab Counselor at 1-800-473-9411. | |
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Kellie King, MS, CGC
Molecular Diagnostic Lab
The Molecular Diagnostic Lab offers DNA analysis for many genetic disorders via gene sequencing, targeted mutation analysis, MLPA deletion/duplication testing, trinucleotide repeat analysis and next generation sequencing panels.