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Lab Dept:
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Anatomic Pathology
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Test Name:
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ACHONDROPLASIA OR HYPOCHONDROPLASIA (FGR3) REFLEX TO REST OF GENE SEQUENCING
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General Information
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Lab Order Codes:
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ACHRF
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Synonyms:
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FRFR3 Gene Sequencing (reflex to remaining exons)
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CPT Codes:
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81479 – Unlisted molecular pathology procedure
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Test Includes:
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Sequencing of the FGFR3 gene for remaining gene specific exons not previously tested in first level testing. First level testing previously performed included exons 3, 5, 7, 9, 10, 13, 15.
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Logistics
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Test Indications:
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Investigation of symptoms characterized by Achondroplasia (ACH)/Hydrochondroplasia (HCH).
ACH respresents the most common skeletal dypslasia in humans. It is characterized by rhizomelic dwarfism, trident hands an short fingers, midface hypoplasia with macrocephaly and fontal bossing. A small foramen magnum may cause generalized hypotonia, hyperrelexia or clonus in newborns. HCH is similar but milder than ACH. Patients are still rhizomelic dwarfs but are not as short, do not have trident hands and the facial manifestations are not as severe. Neurological complications in HCH are not constant findings. HCH is genetically heterogeneous. Not all patients diagnosed clinically with HCH have demonstrable mutations in FGFR3.
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Lab Testing Sections:
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Anatomic Pathology - Sendouts
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Referred to:
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CTGT
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Phone Numbers:
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MIN Lab: 612-813-6280
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STP Lab: 651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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Approximately 2 weeks
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Special Instructions:
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See Patient Preparation. Request special forms for patient consent, physician signature and clinical history from Children’s Laboratory or print Request form here. Select (FGFR3 Reflex to remaining exons) under Achondroplasia (ACH)/Hypochondroplasia (HCH).
Note: These completed forms must accompany the specimen or come with the patient when they present at the lab to be drawn.
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Specimen
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Specimen Type:
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Whole blood
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Container:
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Lavender top (EDTA) tube
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Draw Volume:
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6 mL (Minimum: 4 mL) blood
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Processed Volume:
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Same as Draw Volume
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Collection:
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Routine venipuncture
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Special Processing:
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Lab Staff: Do Not process. Specimen should remain as whole blood in original collection container. Send Monday – Thursday via overnight shipping at refrigerated temperatures. Include patient consent and physician signature forms with the specimen. Forward promptly.
Note: For specimens collected Friday – Sunday (or on a holiday), they should be held in Children’s Laboratories at refrigerated temperatures and shipped on Monday (or the next business day Monday – Thursday).
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Patient Preparation:
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None
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Sample Rejection:
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Frozen specimens; mislabeled or unlabeled specimens
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Interpretive
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Reference Range:
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No mutations detected
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Critical Values:
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N/A
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Limitations:
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Not all patients diagnosed clinically with HCH have demonstrable mutations in FGFR3.
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Methodology:
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DNA Sequencing
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References:
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CTGT Web Page January 2013
Phone: 484-244-2900 Fax: 484-244-2904
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