Extended gene analysis can increase specificity of neonatal screening for cystic fibrosis.
OBJECTIVE
To assess whether carriers and patients can be accurately identified by extended gene analysis for cystic fibrosis (CF) in dried blood spots.


METHODS
A blinded analysis was performed in 10-mm2 blood spots on Guthrie cards, punched as if to remove material for the IRT test, from 10 CF patients and 10 carriers with known CF mutations. Genomic DNA was isolated. Aliquots of 1 microl dissolved DNA were used for subsequent PCRs. Analysis of the deltaF508 mutation was followed by an oligonucleotide ligation assay. Denaturing gradient gel electrophoresis of the whole CFTR gene was carried out in samples with only one identified mutation. Amplicons revealing an aberrant pattern were sequenced.


RESULTS
In all cases, the blood-spot genotype was identical to that previously determined from whole-blood analysis. Estimated time needed to complete the procedure in a series of Guthrie cards was 3-4 wk.


CONCLUSIONS
Extended gene analysis in dried blood spots can discriminate CF patients and carriers. If proven equally reliable in larger series, an approach to neonatal screening in which tests are only considered as screen positive when two CF mutations are found is possible. This can increase the specificity of the screening programme, and carrier detection can practically be avoided.
Mérelle
Marieke E
ME
Department of Paediatrics, Leiden University Medical Centre, Leiden, The Netherlands.
Scheffer
Hans
H
De Jong
Debora
D
Dankert-Roelse
Jeannette E
JE
D000465:Algorithms; D003550:Cystic Fibrosis / Q000097:blood* / Q000235:genetics*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000097:blood* / Q000235:genetics*; D004252:DNA Mutational Analysis; D003951:Diagnostic Errors / Q000517:prevention & control; D004586:Electrophoresis; D006580:Genetic Carrier Screening / Q000379:methods; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D009154:Mutation; D015997:Neonatal Screening / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator