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A L Harris - One of the best experts on this subject based on the ideXlab platform.
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Increased Sensitivity to the prodrug 5 deoxy 5 fluorouridine and modulation of 5 fluoro 2 deoxyuridine Sensitivity in mcf 7 cells transfected with thymidine phosphorylase
1995Co-Authors: Adam V Patterson, H Zhang, Amir Moghaddam, R Bicknell, D C Talbot, I J Stratford, A L HarrisAbstract:Platelet-derived endothelial cell growth factor (PD-ECGF) is identical to human thymidine phosphorylase (dThdPase). The human MCF-7 breast cancer cell line was transfected with the dThdPase cDNA and expressed a 45 kDa protein that was detected with anti-dThdPase antibody. Cell lysates possessed elevated dThdPase activity and cells had up to 165-fold Increased Sensitivity to the prodrug 5'-deoxy-5-fluorouridine (5'-DFUR) in vitro. Sensitivity to 5-fluorouracil (5-FU) and 5-fluoro-2'-deoxyuridine (5-FUdR) was unchanged. Recombinant dThdPase was shown to catalyse directly the phosphorolytic cleavage of 5'-DFUR to 5-FU. Exogenous thymidine (dThd) reversed the toxicity of 5-FUdR on the parental line (1 microM dThd Increased the IC50 value 1000-fold), but the dThd rescue was substantially modulated in the dThdPase-expressing clone 4 (1 microM dThd raised the IC50 value 3-fold). We observed a substantial 'bystander' killing effect when small proportions of dThdPase-expressing cells were mixed with parental MCF-7 cells. dThdPase activity was on average 27-fold higher in breast tumours than in normal breast. The levels of wild-type MCF-7 are similar to the low end of the tumour expression. Thus, in some tumours resistance to 5'-DFUR therapy could be due to low dThdPase activity, and transfection to raise the dThdPase levels within the broad tumour range or above it should markedly enhance Sensitivity to the prodrug. These results confirm that dThdPase is a major pathway in the metabolic activation of 5'-DFUR, and the bystander effect suggests that this may be a suitable enzyme for gene therapy-directed enzyme/prodrug activation therapy.
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Increased Sensitivity to the prodrug 5 deoxy 5 fluorouridine and modulation of 5 fluoro 2 deoxyuridine Sensitivity in mcf 7 cells transfected with thymidine phosphorylase
1995Co-Authors: Adam V Patterson, H Zhang, Amir Moghaddam, R Bicknell, D C Talbot, I J Stratford, A L HarrisAbstract:Platelet-derived endothelial cell growth factor (PD-ECGF) is identical to human thymidine phosphorylase (dThdPase). The human MCF-7 breast cancer cell line was transfected with the dThdPase cDNA and expressed a 45 kDa protein that was detected with anti-dThdPase antibody. Cell lysates possessed elevated dThdPase activity and cells had up to 165-fold Increased Sensitivity to the prodrug 5'-deoxy-5-fluorouridine (5'-DFUR) in vitro. Sensitivity to 5-fluorouracil (5-FU) and 5-fluoro-2'-deoxyuridine (5-FUdR) was unchanged. Recombinant dThdPase was shown to catalyse directly the phosphorolytic cleavage of 5'-DFUR to 5-FU. Exogenous thymidine (dThd) reversed the toxicity of 5-FUdR on the parental line (1 microM dThd Increased the IC50 value 1000-fold), but the dThd rescue was substantially modulated in the dThdPase-expressing clone 4 (1 microM dThd raised the IC50 value 3-fold). We observed a substantial 'bystander' killing effect when small proportions of dThdPase-expressing cells were mixed with parental MCF-7 cells. dThdPase activity was on average 27-fold higher in breast tumours than in normal breast. The levels of wild-type MCF-7 are similar to the low end of the tumour expression. Thus, in some tumours resistance to 5'-DFUR therapy could be due to low dThdPase activity, and transfection to raise the dThdPase levels within the broad tumour range or above it should markedly enhance Sensitivity to the prodrug. These results confirm that dThdPase is a major pathway in the metabolic activation of 5'-DFUR, and the bystander effect suggests that this may be a suitable enzyme for gene therapy-directed enzyme/prodrug activation therapy.
David A Waltz - One of the best experts on this subject based on the ideXlab platform.
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population based newborn screening for genetic disorders when multiple mutation dna testing is incorporated a cystic fibrosis newborn screening model demonstrating Increased Sensitivity but more carrier detections
2004Co-Authors: Anne Marie Comeau, Richard B Parad, Henry L Dorkin, Mark Dovey, Robert S Gerstle, Kenan Haver, Allen Lapey, Brian Osullivan, David A WaltzAbstract:Objectives. Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (ΔF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing). Methods. We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at ∼2 days of age was studied. Results. A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely “genetic diagnosis” was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with ΔF508 alone. Increased Sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with ΔF508 alone. Conclusions. Use of multiple-CFTR-mutation testing improved Sensitivity and postscreening prediction of CF at the cost of Increased referrals and carrier identification.
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population based newborn screening for genetic disorders when multiple mutation dna testing is incorporated a cystic fibrosis newborn screening model demonstrating Increased Sensitivity but more carrier detections
2004Co-Authors: Anne Marie Comeau, Richard B Parad, Henry L Dorkin, Mark Dovey, Robert S Gerstle, Kenan Haver, Allen Lapey, Brian Osullivan, David A WaltzAbstract:OBJECTIVES: Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (DeltaF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing). METHODS: We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at approximately 2 days of age was studied. RESULTS: A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely "genetic diagnosis" was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with DeltaF508 alone. Increased Sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with DeltaF508 alone. CONCLUSIONS: Use of multiple-CFTR-mutation testing improved Sensitivity and postscreening prediction of CF at the cost of Increased referrals and carrier identification.
Richard B Parad - One of the best experts on this subject based on the ideXlab platform.
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population based newborn screening for genetic disorders when multiple mutation dna testing is incorporated a cystic fibrosis newborn screening model demonstrating Increased Sensitivity but more carrier detections
2004Co-Authors: Anne Marie Comeau, Richard B Parad, Henry L Dorkin, Mark Dovey, Robert S Gerstle, Kenan Haver, Allen Lapey, Brian Osullivan, David A WaltzAbstract:Objectives. Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (ΔF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing). Methods. We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at ∼2 days of age was studied. Results. A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely “genetic diagnosis” was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with ΔF508 alone. Increased Sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with ΔF508 alone. Conclusions. Use of multiple-CFTR-mutation testing improved Sensitivity and postscreening prediction of CF at the cost of Increased referrals and carrier identification.
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population based newborn screening for genetic disorders when multiple mutation dna testing is incorporated a cystic fibrosis newborn screening model demonstrating Increased Sensitivity but more carrier detections
2004Co-Authors: Anne Marie Comeau, Richard B Parad, Henry L Dorkin, Mark Dovey, Robert S Gerstle, Kenan Haver, Allen Lapey, Brian Osullivan, David A WaltzAbstract:OBJECTIVES: Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (DeltaF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing). METHODS: We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at approximately 2 days of age was studied. RESULTS: A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely "genetic diagnosis" was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with DeltaF508 alone. Increased Sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with DeltaF508 alone. CONCLUSIONS: Use of multiple-CFTR-mutation testing improved Sensitivity and postscreening prediction of CF at the cost of Increased referrals and carrier identification.
Adam V Patterson - One of the best experts on this subject based on the ideXlab platform.
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Increased Sensitivity to the prodrug 5 deoxy 5 fluorouridine and modulation of 5 fluoro 2 deoxyuridine Sensitivity in mcf 7 cells transfected with thymidine phosphorylase
1995Co-Authors: Adam V Patterson, H Zhang, Amir Moghaddam, R Bicknell, D C Talbot, I J Stratford, A L HarrisAbstract:Platelet-derived endothelial cell growth factor (PD-ECGF) is identical to human thymidine phosphorylase (dThdPase). The human MCF-7 breast cancer cell line was transfected with the dThdPase cDNA and expressed a 45 kDa protein that was detected with anti-dThdPase antibody. Cell lysates possessed elevated dThdPase activity and cells had up to 165-fold Increased Sensitivity to the prodrug 5'-deoxy-5-fluorouridine (5'-DFUR) in vitro. Sensitivity to 5-fluorouracil (5-FU) and 5-fluoro-2'-deoxyuridine (5-FUdR) was unchanged. Recombinant dThdPase was shown to catalyse directly the phosphorolytic cleavage of 5'-DFUR to 5-FU. Exogenous thymidine (dThd) reversed the toxicity of 5-FUdR on the parental line (1 microM dThd Increased the IC50 value 1000-fold), but the dThd rescue was substantially modulated in the dThdPase-expressing clone 4 (1 microM dThd raised the IC50 value 3-fold). We observed a substantial 'bystander' killing effect when small proportions of dThdPase-expressing cells were mixed with parental MCF-7 cells. dThdPase activity was on average 27-fold higher in breast tumours than in normal breast. The levels of wild-type MCF-7 are similar to the low end of the tumour expression. Thus, in some tumours resistance to 5'-DFUR therapy could be due to low dThdPase activity, and transfection to raise the dThdPase levels within the broad tumour range or above it should markedly enhance Sensitivity to the prodrug. These results confirm that dThdPase is a major pathway in the metabolic activation of 5'-DFUR, and the bystander effect suggests that this may be a suitable enzyme for gene therapy-directed enzyme/prodrug activation therapy.
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Increased Sensitivity to the prodrug 5 deoxy 5 fluorouridine and modulation of 5 fluoro 2 deoxyuridine Sensitivity in mcf 7 cells transfected with thymidine phosphorylase
1995Co-Authors: Adam V Patterson, H Zhang, Amir Moghaddam, R Bicknell, D C Talbot, I J Stratford, A L HarrisAbstract:Platelet-derived endothelial cell growth factor (PD-ECGF) is identical to human thymidine phosphorylase (dThdPase). The human MCF-7 breast cancer cell line was transfected with the dThdPase cDNA and expressed a 45 kDa protein that was detected with anti-dThdPase antibody. Cell lysates possessed elevated dThdPase activity and cells had up to 165-fold Increased Sensitivity to the prodrug 5'-deoxy-5-fluorouridine (5'-DFUR) in vitro. Sensitivity to 5-fluorouracil (5-FU) and 5-fluoro-2'-deoxyuridine (5-FUdR) was unchanged. Recombinant dThdPase was shown to catalyse directly the phosphorolytic cleavage of 5'-DFUR to 5-FU. Exogenous thymidine (dThd) reversed the toxicity of 5-FUdR on the parental line (1 microM dThd Increased the IC50 value 1000-fold), but the dThd rescue was substantially modulated in the dThdPase-expressing clone 4 (1 microM dThd raised the IC50 value 3-fold). We observed a substantial 'bystander' killing effect when small proportions of dThdPase-expressing cells were mixed with parental MCF-7 cells. dThdPase activity was on average 27-fold higher in breast tumours than in normal breast. The levels of wild-type MCF-7 are similar to the low end of the tumour expression. Thus, in some tumours resistance to 5'-DFUR therapy could be due to low dThdPase activity, and transfection to raise the dThdPase levels within the broad tumour range or above it should markedly enhance Sensitivity to the prodrug. These results confirm that dThdPase is a major pathway in the metabolic activation of 5'-DFUR, and the bystander effect suggests that this may be a suitable enzyme for gene therapy-directed enzyme/prodrug activation therapy.
Anne Marie Comeau - One of the best experts on this subject based on the ideXlab platform.
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population based newborn screening for genetic disorders when multiple mutation dna testing is incorporated a cystic fibrosis newborn screening model demonstrating Increased Sensitivity but more carrier detections
2004Co-Authors: Anne Marie Comeau, Richard B Parad, Henry L Dorkin, Mark Dovey, Robert S Gerstle, Kenan Haver, Allen Lapey, Brian Osullivan, David A WaltzAbstract:Objectives. Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (ΔF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing). Methods. We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at ∼2 days of age was studied. Results. A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely “genetic diagnosis” was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with ΔF508 alone. Increased Sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with ΔF508 alone. Conclusions. Use of multiple-CFTR-mutation testing improved Sensitivity and postscreening prediction of CF at the cost of Increased referrals and carrier identification.
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population based newborn screening for genetic disorders when multiple mutation dna testing is incorporated a cystic fibrosis newborn screening model demonstrating Increased Sensitivity but more carrier detections
2004Co-Authors: Anne Marie Comeau, Richard B Parad, Henry L Dorkin, Mark Dovey, Robert S Gerstle, Kenan Haver, Allen Lapey, Brian Osullivan, David A WaltzAbstract:OBJECTIVES: Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (DeltaF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing). METHODS: We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at approximately 2 days of age was studied. RESULTS: A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely "genetic diagnosis" was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with DeltaF508 alone. Increased Sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with DeltaF508 alone. CONCLUSIONS: Use of multiple-CFTR-mutation testing improved Sensitivity and postscreening prediction of CF at the cost of Increased referrals and carrier identification.
