engleski

NEONATAL SCREENING FOR CYSTIC FIBROSIS USING IMMUNOREACTIVE TRYPSINOGEN AND DIRECT GENE ANALYSIS IN SLOVENIA

Subjects. 28 472 neonates born in Slovenia between October 1994 and March 1996. No selection criteria were applied. Material and methods. Guthrie cards routinely collected as part of a wider neonatal screening programme. Immunoreactive trypsinogen (IRT) analysis (Delfia) followed by Direct gene study was performed on dried blood specimens of newborns with IRT test  70 g/l). Molecular analysis was done by DGGE followed by direct DNA sequencing, if necessary. Systematic scanning of exons 10, 11, 19 and 20 of the CFTR gene was used in order to screen most frequent mutations in Slovene population. Results. 328 blood spot samples (1, 15 %) with IRT concentrations  70 g/l were selected for direct gene analysis. Four were from affected neonates. Three compound heterozygotes:  F508/Q552X ;  F508/R1162X ; G542X/N were immediately directed for management of CF. Parents were given genetic counseling. The fourth, negative for four analysed exons, deceased at age of one month had meconium ileus and bronchopneumonia. 16 infants were heterozygous:  F508(10), G542X(2) and by one had: R1162X, R553X, A559T and 3905 ins T. All heterozygotes were recalled for second IRT, sweat testing and clinical examination. Families were offered genetic counseling and cascade testing ( 47 persons). Conclusion. According to the original strategy combining IRT screening at the fifth day of life with the search for mutations in the four exons of the gene that allows the identification of 78.5% of the mutated alleles (Audrezet et al. Hum Genet 1994 ; 93:659-62), the incidence of CF patients in Slovenia is 1:7118. Therefore the couples in which one partner is a carrier and the other one is negative for four tested exons, the risk of having an affected child decreases from 1:168 to 1:800. 15 months after last screening, no false negative results were reported. Only 77 (0, 27%) children and their families have been recalled. The sensibility of the test during this period was 100% and the percentage of false positive was 0.28%. Reevaluation of these results, 12 years after, should determine more exact sensibility of the test. Supported by grants EEC N°BMH1CT 921391 and Ministry of Science and Technology Republic of Slovenia N° P3-5261-0312-93-96.

IMMUNOREACTIVE TRYPSINOGEN; CFTR ANALYSIS; NEONATA SCREENING; SLOVENIA

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