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Scott D. Grosse - One of the best experts on this subject based on the ideXlab platform.
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observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in africa and the middle east deviations from hardy weinberg equilibrium
Genetics in Medicine, 2016Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index FIS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance (P < 0.05) in 24. High FIS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on FIS, was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East). Genet Med 18 3, 265–274.
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Observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in Africa and the Middle East: deviations from Hardy-Weinberg equilibrium
Genetics in Medicine, 2016Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Genet Med 18 3, 265–274. Purpose: Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. Methods: We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index F _ IS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Results: Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance ( P < 0.05) in 24. High F _ IS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on F _ IS , was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Conclusion: Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East).
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Observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in Africa and the Middle East: deviations from Hardy-Weinberg equilibrium
Genetics in Medicine, 2015Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index FIS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance (P < 0.05) in 24. High FIS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on FIS, was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East). Genet Med 18 3, 265–274.
Frédéric B. Piel - One of the best experts on this subject based on the ideXlab platform.
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observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in africa and the middle east deviations from hardy weinberg equilibrium
Genetics in Medicine, 2016Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index FIS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance (P < 0.05) in 24. High FIS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on FIS, was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East). Genet Med 18 3, 265–274.
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Observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in Africa and the Middle East: deviations from Hardy-Weinberg equilibrium
Genetics in Medicine, 2016Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Genet Med 18 3, 265–274. Purpose: Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. Methods: We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index F _ IS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Results: Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance ( P < 0.05) in 24. High F _ IS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on F _ IS , was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Conclusion: Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East).
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Observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in Africa and the Middle East: deviations from Hardy-Weinberg equilibrium
Genetics in Medicine, 2015Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index FIS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance (P < 0.05) in 24. High FIS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on FIS, was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East). Genet Med 18 3, 265–274.
Wolfgang J. Schnedl - One of the best experts on this subject based on the ideXlab platform.
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silent Hemoglobin Variants and determination of hba1c with the high resolution program of the hplc ha 8160 Hemoglobin analyzer
Clinical Biochemistry, 2005Co-Authors: Wolfgang J. Schnedl, Theresa Lahousen, Sandra J Wallner, Robert Krause, Rainer W. LippAbstract:Objectives: Evaluation of HbA1c determination with an automated ion-exchange high-performance liquid chromatography (HPLC) method in patients with clinically silent Hemoglobin (Hb) Variants. Design and methods: HbA1c values were determined with the Arkray HA-8160 ion-exchange HPLC using the high-resolution, 4.2-min h-thalassemia screening mode in patients with silent Hemoglobin (Hb) Variants, namely, Hb Graz, Hb Sherwood Forest, Hb O Padova, and HbD. Results: All of these Hemoglobin Variants caused additional peaks in the chromatograms, without HbA1c results in patients with Hb Graz and Hb Sherwood Forest, and demonstrated extra peaks with HbA1c results that were clinically too low for patients with Hb O Padova and in the patient with HbD. Conclusions: The development of this automated HPLC method modification with high-resolution h-thalassemia screening mode aids identification of interference due to some clinically silent Hb Variants in HbA1c determination. D 2004 The Canadian Society of Clinical Chemists. All rights reserved.
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Determination of glycated Hemoglobin in clinically silent Hemoglobin Variants.
Diabetes metabolism research and reviews, 2004Co-Authors: Wolfgang J. Schnedl, Rainer W. Lipp, Theresa Lahousen, Thomas Lang, Satoshi Yonehara, Satoshi Fukunaga, Toshihiro Imai, Randie R. LittleAbstract:Background Evaluation of glycated Hemoglobin determination methods in patients with clinically silent Hemoglobin Variants. Methods HbA1c results were determined with various methods, including a new enzymatic assay, a boronate affinity HPLC, immunoassays and ion-exchange HPLC in patients with the clinically silent Hemoglobin Variants Hb Graz, Hb Sherwood Forest, Hb D and Hb O Padova. Results The effect of Hemoglobin Variants on glycated Hemoglobin determination was method-dependent. The enzymatic and boronate affinity HPLC method did not interfere with any of the Variants evaluated. In contrast, Hb Graz interfered with all immunoassay and ion-exchange HPLC methods evaluated. The Tosoh ion-exchange HPLC method HLC-723 did not detect the late migrating Hb O Padova in the chromatogram, but this Hemoglobin variant still interfered causing artificially low HbA1c results. Conclusions Our study underscores the need for clinical laboratories and physicians to be aware of the limitations of their HbA1c assay methods as well as the importance of visual inspection of ion-exchange chromatograms to detect abnormalities caused by the Hemoglobin Variants. Samples with clinically silent Hb Variants should be analyzed by a second method with a different assay principle, preferably a boronate affinity HPLC or an enzymatic assay. Copyright © 2004 John Wiley & Sons, Ltd.
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Hemoglobin Variants recently detected in Austria.
Annals of hematology, 1995Co-Authors: Wolfgang J. Schnedl, E. C. Reisinger, Rainer W. Lipp, Guenter J. Krejs, P. HopmeierAbstract:Measurement of glycated Hemoglobin (HbA1c) is used for routine management of diabetic patients. Glucose linkage to HbA1c reflects mean blood glucose levels during the last 3 months before examination. Various methods for HbA1c determination show abnormal values with Hemoglobin Variants. In some diabetic patients excessively high HbA1c values with high-performance liquid chromatography (HPLC) led to the detection of Hb Graz. In addition to Hb Graz, other silent Hemoglobin Variants have been found in Austria. Here we review Hb Graz, Hb Sherwood Forest, and Hb Okayama detected while using HPLC for the measurement of HbA1c in diabetic patients.
Rainer W. Lipp - One of the best experts on this subject based on the ideXlab platform.
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silent Hemoglobin Variants and determination of hba1c with the high resolution program of the hplc ha 8160 Hemoglobin analyzer
Clinical Biochemistry, 2005Co-Authors: Wolfgang J. Schnedl, Theresa Lahousen, Sandra J Wallner, Robert Krause, Rainer W. LippAbstract:Objectives: Evaluation of HbA1c determination with an automated ion-exchange high-performance liquid chromatography (HPLC) method in patients with clinically silent Hemoglobin (Hb) Variants. Design and methods: HbA1c values were determined with the Arkray HA-8160 ion-exchange HPLC using the high-resolution, 4.2-min h-thalassemia screening mode in patients with silent Hemoglobin (Hb) Variants, namely, Hb Graz, Hb Sherwood Forest, Hb O Padova, and HbD. Results: All of these Hemoglobin Variants caused additional peaks in the chromatograms, without HbA1c results in patients with Hb Graz and Hb Sherwood Forest, and demonstrated extra peaks with HbA1c results that were clinically too low for patients with Hb O Padova and in the patient with HbD. Conclusions: The development of this automated HPLC method modification with high-resolution h-thalassemia screening mode aids identification of interference due to some clinically silent Hb Variants in HbA1c determination. D 2004 The Canadian Society of Clinical Chemists. All rights reserved.
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Determination of glycated Hemoglobin in clinically silent Hemoglobin Variants.
Diabetes metabolism research and reviews, 2004Co-Authors: Wolfgang J. Schnedl, Rainer W. Lipp, Theresa Lahousen, Thomas Lang, Satoshi Yonehara, Satoshi Fukunaga, Toshihiro Imai, Randie R. LittleAbstract:Background Evaluation of glycated Hemoglobin determination methods in patients with clinically silent Hemoglobin Variants. Methods HbA1c results were determined with various methods, including a new enzymatic assay, a boronate affinity HPLC, immunoassays and ion-exchange HPLC in patients with the clinically silent Hemoglobin Variants Hb Graz, Hb Sherwood Forest, Hb D and Hb O Padova. Results The effect of Hemoglobin Variants on glycated Hemoglobin determination was method-dependent. The enzymatic and boronate affinity HPLC method did not interfere with any of the Variants evaluated. In contrast, Hb Graz interfered with all immunoassay and ion-exchange HPLC methods evaluated. The Tosoh ion-exchange HPLC method HLC-723 did not detect the late migrating Hb O Padova in the chromatogram, but this Hemoglobin variant still interfered causing artificially low HbA1c results. Conclusions Our study underscores the need for clinical laboratories and physicians to be aware of the limitations of their HbA1c assay methods as well as the importance of visual inspection of ion-exchange chromatograms to detect abnormalities caused by the Hemoglobin Variants. Samples with clinically silent Hb Variants should be analyzed by a second method with a different assay principle, preferably a boronate affinity HPLC or an enzymatic assay. Copyright © 2004 John Wiley & Sons, Ltd.
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Hemoglobin Variants recently detected in Austria.
Annals of hematology, 1995Co-Authors: Wolfgang J. Schnedl, E. C. Reisinger, Rainer W. Lipp, Guenter J. Krejs, P. HopmeierAbstract:Measurement of glycated Hemoglobin (HbA1c) is used for routine management of diabetic patients. Glucose linkage to HbA1c reflects mean blood glucose levels during the last 3 months before examination. Various methods for HbA1c determination show abnormal values with Hemoglobin Variants. In some diabetic patients excessively high HbA1c values with high-performance liquid chromatography (HPLC) led to the detection of Hb Graz. In addition to Hb Graz, other silent Hemoglobin Variants have been found in Austria. Here we review Hb Graz, Hb Sherwood Forest, and Hb Okayama detected while using HPLC for the measurement of HbA1c in diabetic patients.
Thomas N. Williams - One of the best experts on this subject based on the ideXlab platform.
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observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in africa and the middle east deviations from hardy weinberg equilibrium
Genetics in Medicine, 2016Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index FIS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance (P < 0.05) in 24. High FIS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on FIS, was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East). Genet Med 18 3, 265–274.
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Observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in Africa and the Middle East: deviations from Hardy-Weinberg equilibrium
Genetics in Medicine, 2016Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Genet Med 18 3, 265–274. Purpose: Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. Methods: We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index F _ IS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Results: Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance ( P < 0.05) in 24. High F _ IS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on F _ IS , was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Conclusion: Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East).
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Observed and expected frequencies of structural Hemoglobin Variants in newborn screening surveys in Africa and the Middle East: deviations from Hardy-Weinberg equilibrium
Genetics in Medicine, 2015Co-Authors: Frédéric B. Piel, Thomas V. Adamkiewicz, Djesika D. Amendah, Thomas N. Williams, Sunetra Gupta, Scott D. GrosseAbstract:Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural Hemoglobin Variants. We conducted a systematic review of newborn screening surveys of Hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index FIS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Sixty samples reported genotype counts for Hemoglobin Variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance (P < 0.05) in 24. High FIS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on FIS, was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East. Differences between observed and expected genotype frequencies are common in surveys of Hemoglobin Variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East). Genet Med 18 3, 265–274.