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insufficiency. The incidence of CF varies markedly among different populations, as does the mutation
detection rate for the mutation screening assay. To date, over 1,500 mutations have been described within
the CF gene, named cystic fibrosis transmembrane conductance regulator (CFTR). The most common
mutation, deltaF508, accounts for approximately 67% of the mutations worldwide and approximately
70% to 75% in a North American Caucasian population. Most of the remaining mutations are rather rare,
although some show a relatively higher prevalence in certain ethnic groups or in some atypical
presentations of CF such as congenital bilateral absence of the vas deferens (CBAVD). Mutations
detected by the assay performed in the Mayo Clinic Molecular Genetics Laboratory include the 23
mutations recommended by the American College of Medical Genetics as well as 83 other mutations. Of
note, CFTR potentiator therapies may improve clinical outcomes for patients with a clinical diagnosis of
CF and at least 1 copy of the G551D mutation. These 106 mutations account for approximately 91% of
CF chromosomes in a Northern European Caucasian population. Detection rates for several ethnic and
racial groups are listed in the table below. Note that interpretation of test results and risk calculations are
also dependent on clinical information and family history. Racial or Ethnic Group Carrier Frequency
Mutation Detection Rate* African American 1/65 81% Ashkenazi Jewish 1/25 97% Asian American
(excluding individuals of Japanese ancestry) 1/90 54% Mixed European 1/25 82% Eastern European 1/25
77% French Canadian 1/25 91% Hispanic American 1/46 82% Northern European 1/25 91% Southern
European 1/25 79% *Rates are for classical CF. Rates are lower for atypical forms of CF and for
CBAVD. CFTR mutations listed below are included in this panel. Deletion exons 2-3 Exon 11: R553X
Intron 2: 296+2 T->A Exon 11: A559T Exon 3: E60X Exon 11: R560T Exon 3: R75X Intron 11:
1811+1.6kb A->G Exon 3: G85E Intron 11: 1812-1 G->A Exon 3: 394delTT Intron 12: 1898+1 G->A
Intron 3: 405+1 G->A Intron 12: 1898+1 G->T Intron 3: 406-1 G->A Intron 12: 1898+1 G->C Exon 4:
E92X Intron 12: 1898+5 G->T Exon 4: 444delA Exon 12: P574H Exon 4: 457TAT->G Exon 13:
1949del84 Exon 4: R117H Exon 13: 2043delG Exon 4: R117C Exon 13: 2055del9->A Exon 4: Y122X
Exon 13: 2105del13ins5 Exon 4: 574delA Exon 13: 2108delA Intron 4: 621+1 G->T Exon 13: 2143delT
Exon 5: 663delT Exon 13: 2183AA->G Exon 5: G178R Exon 13: 2184delA Intron 5: 711+1 G->T Exon
13: 2184insA Intron 5: 711+5 G->A Exon 13: R709X Intron 5: 712-1 G->T Exon 13: K710X Exon 6a:
H199Y Exon 13: 2307insA Exon 6a: P205S Exon 13: R764X Exon 6a: L206W Intron 14b: 2789+5 G->A
Exon 6a: 852del22 Exon 15: 2869insG Exon 6b: 935delA Exon 15: Q890X Exon 6b: 936delTA Intron
16: 3120+1 G->A Exon 7: deltaF311 Exon 17a: 3171delC Exon 7: 1078delT Exon 17a: 3199del6 Exon 7:
G330X Exon 17b: R1066C Exon 7: R334W Exon 17b: W1089X Exon 7: T338I Exon 17b: Y1092X
(C->G) Exon 7: R347P Exon 17b: Y1092X (C->A) Exon 7: R347H Exon 17b: M1101K Exon 7: R352Q
Exon 17b: M1101R Exon 7: Q359K Exon 18: D1152H Exon 7: T360K Exon 19: R1158X Exon 8:
1288insTA Exon 19: R1162X Exon 9: A455E Exon 19: 3659delC Exon 10: S466X (C->A) Exon 19:
3667del4 Exon 10: S466X (C->G) Exon 19: S1196X Exon 10: G480C Exon 19: W1204X Exon 10:
Q493X Exon 19: 3791delC Exon 10: deltaI507 Exon 19: Q1238X Exon 10: deltaF508 Intron 19:
3849+10kb C->T Exon 10: 1677delTA Exon 20: 3876delA Exon 10: C524X Exon 20: S1251N Intron 10:
1717-1 G->A Exon 20: S1255X Exon 11: G542X Exon 20: 3905insT Exon 11: S549N Exon 20: W1282X
Exon 11: S549R Exon 21: 4016insT Exon 11: G551D Exon 21: N1303K (C->A) Exon 11:Q552X Exon
21: N1303K (C->G) See Cystic Fibrosis Molecular Diagnostic Testing Algorithm in Special Instructions
for additional information.
Useful For: Confirmation of a clinical diagnosis of cystic fibrosis Risk refinement via carrier screening
for individuals in the general population Prenatal diagnosis or familial mutation testing when the familial
mutations are included in the 106-mutation panel listed above (if familial mutations are not included in
the 106-mutation panel, order CFTRK/88880 CFTR Gene, Known Mutation) Risk refinement via carrier
screening for individuals with a family history when familial mutations are not available Identification of
patients who may respond to CFTR potentiator therapy
Interpretation: An interpretive report will be provided.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Quint A, Lerer I, Sagi M, Abeliovich D: Mutation spectrum in Jewish cystic
fibrosis patients in Israel: implication to carrier screening. Am J Med Genet A 2005;136(3):246-248 2.
Bobadilla JL, Macek M, Fine FP, Farrell PM: Cystic fibrosis: a worldwide analysis of CFTR
mutations-correlation with incidence data and application to screening. Hum Mutat 2002;19(6):575-606 3.
Sugarman EA, Rohlfs EM, Silverman LM, Alitto BA: CFTR mutation distribution among U.S. Hispanic
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