Background:
Cystic Fibrosis (CF) is the most common autosomal recessive genetic disease in the Caucasian population appearing in approximately one in every 2,500 newborns. In the Caucasian and Ashkenazi Jewish populations, about one in every 25 individuals carries one copy of a mutation in the CFTR gene at 7q31.2.
Reasons for Referral:
- Confirmation of clinical diagnosis
- Carrier identification in persons with a positive or negative family history
- Reflex testing for newborn screening
- Testing of Sperm & egg donors
- Abnormal fetal ultrasound
- Preconception and carrier screening
Methodology:
Direct Mutation Analysis: Bead-based array methodology tests for 60 CFTR variants including all of the variants in the ACMG/ACOG-recommended mutation panel:
ACMG/ACOG panel
ΔF508 |
R553X |
R117H |
1898+1G>A |
R1162X |
711+1G>T |
ΔI507 |
G542X |
621+1G→T |
R334W |
2184delA |
3659delC |
2789+5G>A |
G551D |
N1303K |
R347P |
1717-1G→A |
W1282X |
A455E |
R560T |
G85E |
3120+1G→A |
3849+10kbC→T |
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Additional variants:
1078delT |
394delTT |
Y122X |
R347H |
V520F |
A559T |
S549N |
S549R(T>G) |
1898+5G>T |
2183AA>G |
2307insA |
Y1092X |
M1101K |
S1255X |
3876delA |
3905insT |
E60X |
R75X |
406-1G>A |
G178R |
L206W |
935delA |
G330X |
Q493X |
1677delTA |
2055del9>A |
2143delT |
K710X |
3791delC |
Q890X |
3199del6 |
R1066C |
W1089X |
D1152H |
R1158X |
CFTRdele2,3 |
S1196X |
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Additionally, 5T/7T/9T tract is reported for R117H carriers. Reflex testing for I506V and I507V is performed only when indicated.
Mutation Analysis:
91% detection in the Caucasian/non-Ashkenazic population
96% detection in the Ashkenazic population
73% detection in the African-American population
84% detection in the Hispanic-American population
55% detection in the Asian-American population
Test reporting follows the American College of Medical Genetics (ACMG) guidelines.
Specimen Requirements:
Blood: Lavender tube (EDTA) or yellow (ACD)
- Adult: 6.0 mL
- Child: 6.0 mL
- Infant: 2.0 mL
Saliva: 2 ORAgene Saliva Kit(s) (OGR-500) used according to manufacturer instructions. Please contact KDL Client Services for a Saliva Collection Kit for patients that cannot provide a blood sample.
Assisted Saliva: 4 ORAgene™ Assisted Saliva Collection Kits (OGR-575) used according to manufacturer instructions. Please contact KDL Client Services for an Assisted Saliva Collection Kit for patients that cannot provide a blood sample.
Buccal Swab: Please contact KDL Client Services for Buccal Swab Collection Kit(s) for patients that cannot provide a blood sample.
DNA: 50ng at a minimum of 10ng/µL
Prenatal:
- Direct Amniotic Fluid (10-20mL)
- Direct CVS
- Direct POC
- Cultured Amnio (2-T25 flasks)
- Cultured CVS (2-T25 flasks)
- Cultured Fetal Tissue: Product of Conception (2 T-25 flasks)
- Cord blood
Notice Regarding Molecular Genetic Testing on CVS or Amniotic Fluid Specimens:
- Maternal cell rule-out testing will be performed on all prenatal specimens received. Pease provide maternal blood in addition to the fetal specimen. Additional charges apply for the maternal cell rule-out test.
For routine testing of blood, saliva and buccal swabs, KDL does NOT accept samples from patients within two (2) weeks of a packed cell/platelet transfusion or within four (4) weeks of a whole blood transfusion. For extraordinary circumstances, where testing must be performed outside of the above windows, please contact our lab.
A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES. Please include detailed clinical information, including ethnicity, clinical history, and family history.
Test Performed (Days):
Weekly
Turn Around Time:
7-10 days
Shipment Sensitivity Requirements:
- Keep specimen cool during transit, but do not ship on dry ice.
- Please use the cold pack provided in the KDL shipping kit.
- Ship the specimen overnight express, using the FedEx priority overnight label provided.
- Please contact Client Services at (855) 535-1522 for shipping kits and instructions.
References:
- Schneider M. et al, 2007 Clin Genet 72:30-38.
Additional Info:
Full CFTR Sanger sequencing and MLPA for large deletions and duplications tests are also available.
Prior to any genetic testing we recommend genetic counseling. To receive forms and information about prenatal diagnostic testing, please contact Client Services at (855) 535-1522.