Sikkelcelziekte in de hielprikscreening. II

OBJECTIVE: Evaluation of the reporting of sickle cell trait during the first year (2007) in which sickle cell disease has been included in heel prick screening in the Netherlands. DESIGN: Descriptive. METHOD: Reporting of the number of children identified as having sickle cell trait and the number of subsequent referrals by general practitioners to 2 clinical genetics centres (CGC), at the Academic Medical Center in Amsterdam and the Erasmus MC in Rotterdam. RESULTS: In the first year sickle cell trait was found in 806 children. Only 20 couples were referred to the 2 CGCs, and these did not include any at-risk couples i.e. couples in which both partners have sickle cell trait. CONCLUSION: There is still a lack of clarity among primary care providers concerning the role of the general practitioner and of the midwife in the reportage procedure for sickle cell trai

Establishing New Cut-Off Limits for Galactose 1-Phosphate-Uridyltransferase Deficiency for the Dutch Newborn Screening Programme

Newborn screening for classical galactosemia in the Netherlands is performed by five laboratories and is based on the measurement of galactose 1-phosphate-uridyltransferase (GALT) activity and total galactose (TGAL) in heel prick blood spots. Unexpected problems with the GALT assay posed a challenge to switch to a new assay. The aim of this study was to make an analytical and clinical evaluation of GALT assays to replace the current assay and to establish new cut-off values (COVs).First, the manual assay from PerkinElmer (NG-1100) and the GSP assay were compared by analyzing 626 anonymous heel prick samples in parallel. Secondly, a manual GSP method was evaluated and 2,052 samples were compared with the automated GSP assay. Finally, a clinical evaluation was performed by collecting data from 93 referred newborns.No satisfactory correlation was observed between GALT activity measured with the manual NG-1100 assay and the automated GSP assay. An acceptable correlation was found between the manual and automated GSP assay. Intra- and inter-assay variation of the automated GSP were 1.8-10.0% and 3.1-13.9%, respectively. Evaluation of clinical data demonstrated that adjusting the COVs for GALT to 2.0 U/dl and TGAL to 1,100 μmol/l improved specificity of screening for classical galactosemia.An assay designed for automated processing to measure GALT activity in heel prick samples works equally well when processed manually. We therefore adopted both methods in the Dutch screening laboratories. As a result of this evaluation new COVs for GALT and TGAL have been introduced and are valid from July 2015

Recommendations for newborn screening for galactokinase deficiency: A systematic review and evaluation of Dutch newborn screening data.

Galactokinase (GALK) deficiency causes cataract leading to severe developmental consequences unless treated early. Because of the easy prevention and rapid reversibility of cataract with treatment, the Dutch Health Council advised to include GALK deficiency in the Dutch newborn screening program. The aim of this study is to establish the optimal screening method and cut-off value (COV) for GALK deficiency screening by performing a systematic review of the literature of screening strategies and total galactose (TGAL) values and by evaluating TGAL values in the first week of life in a cohort of screened newborns in the Netherlands

Optimization of performance of Dutch newborn screening for cystic fibrosis.

Dutch protocol consists of four steps: determination of immunoreactive trypsinogen (IRT) and pancreatitis-associated protein (PAP), DNA analysis by INNO-LiPA and extended gene analysis (EGA). For the optimization phase we used results of 556,952 newborns screened between April 2011 and June 2014 to calculate effects of 13 alternative protocols on sensitivity, specificity, PPV, ratios of CF to other diagnoses, and costs. One alternative protocol was selected based on calculated sensitivity, PPV and costs and was implemented on 1st July 2016. In this modified protocol DNA analysis is performed in samples with a combination of IRT ≥60 µg/l and PAP ≥3.0 µg/l, IRT ≥100 µg/l and PAP ≥1.2 µg/l or IRT ≥124 µg/l and PAP not relevant. Results of 599,137 newborns screened between 1st July 2016 and 31st December 2019 were similarly evaluated as in the optimization phase

Newborn blood spot screening for cystic fibrosis with a four-step screening strategy in the Netherlands.

Newborn screening for cystic fibrosis (NBSCF) was introduced in the Dutch NBS program in 2011 with a novel strategy

Newborn blood spot screening for cystic fibrosis with a four-step screening strategy in the Netherlands.

Newborn screening for cystic fibrosis (NBSCF) was introduced in the Dutch NBS program in 2011 with a novel strategy

Critical evaluation of the newborn screening for congenital hypothyroidism in the Netherlands

Objective: Congenital hypothyroidism (CH) is defined as thyroid hormone deficiency at birth due to disorders of the thyroid gland (thyroidal CH, CH-T), or the hypothalamus or pituitary (central CH, CH-C). The Dutch Newborn Screening (NBS) strategy is primarily based on determination of thyroxine (T4) concentrations in dried blood spots followed, if necessary, by thyroid-stimulating hormone (TSH) and thyroxine-binding globulin (TBG) measurement enabling detection of both CH-T and CH-C. A calculated T4/TBG ratio serves as an indirect measure for free T4. A T4/TBG ratio ≤ 17 in a second heel puncture is suggestive of CH-C. Design and methods: In the present study, we evaluated 11 years of Dutch CH NBS using a database of referred cases by assessing the contribution of each criterion in the unique stepwise T4-TSH-TBG NBS algorithm. Results: Between 2007 and the end of 2017, 1 963 465 newborns were screened in the Netherlands. Use of the stepwise algorithm led to 3044 referrals and the identification of 612 CH cases, consisting of 496 CH-T, 86 CH-C, and 30 CH of unknown origin diagnoses. We detected 62.8% of CH-C cases by the T4/TBG ratio in the second heel puncture. The positive predictive value (PPV) of the stepwise T4-TSH-TBG NBS algorithm was 21.0%. Conclusion: This evaluation shows that the Dutch stepwise T4-TSH-TBG NBS algorithm with a calculated T4/TBG ratio is of great value for the detection of both CH-T and CH-C in the Netherlands, at the cost of a lower PPV compared to TSH-based NBS strategies

Maleic acid is a biomarker for maleylacetoacetate isomerase deficiency; implications for newborn screening of tyrosinemia type 1.

: Dried blood spot succinylacetone (SA) is often used as a biomarker for newborn screening (NBS) for tyrosinemia type 1 (TT1). However, false-positive SA results are often observed. Elevated SA may also be due to maleylacetoacetate isomerase deficiency (MAAI-D), which appears to be clinically insignificant. This study investigated whether urine organic acid (uOA) and quantitative urine maleic acid (Q-uMA) analyses can distinguish between TT1 and MAAI-D. We reevaluated/measured uOA (GC-MS) and/or Q-uMA (LC-MS/MS) in available urine samples of nine referred newborns (2 TT1, 7 false-positive), eight genetically confirmed MAAI-D children, and 66 controls. Maleic acid was elevated in uOA of 5/7 false-positive newborns and in the three available samples of confirmed MAAI-D children, but not in TT1 patients. Q-uMA ranged from not detectable to 1.16 mmol/mol creatinine in controls (n = 66) and from 0.95 to 192.06 mmol/mol creatinine in false-positive newborns and MAAI-D children (n = 10). MAAI-D was genetically confirmed in 4/7 false-positive newborns, all with elevated Q-uMA, and rejected in the two newborns with normal Q-uMA. No sample was available for genetic analysis of the last false-positive infant with elevated Q-uMA. Our study shows that MAAI-D is a recognizable cause of false-positive TT1 NBS results. Elevated urine maleic acid excretion seems highly effective in discriminating MAAI-D from TT1

Critical evaluation of the newborn screening for congenital hypothyroidism in the Netherlands.

Objective: Congenital hypothyroidism (CH) is defined as thyroid hormone de ficiency at birth due to disorders of the thyroid gland (thyroidal CH, CH-T), or the hypothalamus or pitu itary (central CH, CH-C). The Dutch Newborn Screening (NBS) strategy is primarily based on determination of thyroxine (T4) concentrations in dried blood spots followed, if necessary, by thyroid-stimulating hormone (TSH) and thyroxin e-binding globulin (TBG) measurement enabling detection of both CH-T and CH-C. A calculated T4/TBG ratio serv es as an indirect measure for free T4. A T4/TBG ratio . 17 in a second heel puncture is suggestive of CH-C. Design and methods: In the present study, we evaluated 11 years of Dutch CH NBS us ing a database of referred cases by assessing the contribution of each criterion in the unique s tepwise T4-TSH-TBG NBS algorithm. Results: Between 2007 and the end of 2017, 1 963 465 newborns were scre ened in the Netherlands. Use of the stepwise algorithm led to 3044 referrals and the identification of 612 CH cases, consisting of 496 CH-T, 86 CH-C, and 30 CH of unknown origin diagnoses. We detected 62.8% of CH-C ca ses by the T4/TBG ratio in the second heel puncture. The positive predictive value (PPV) of the stepwise T 4-TSH-TBG NBS algorithm was 21.0%. Conclusion: This evaluation shows that the Dutch stepwise T4-TSH-TBG NBS a lgorithm with a calculated T4/TBG ratio is of great value for the detection of both CH-T and CH-C in the N etherlands, at the cost of a lower PPV compared to TSHbased NBS strategies

Critical evaluation of the newborn screening for congenital hypothyroidism in the Netherlands

Objective: Congenital hypothyroidism (CH) is defined as thyroid hormone de ficiency at birth due to disorders of the thyroid gland (thyroidal CH, CH-T), or the hypothalamus or pitu itary (central CH, CH-C). The Dutch Newborn Screening (NBS) strategy is primarily based on determination of thyroxine (T4) concentrations in dried blood spots followed, if necessary, by thyroid-stimulating hormone (TSH) and thyroxin e-binding globulin (TBG) measurement enabling detection of both CH-T and CH-C. A calculated T4/TBG ratio serv es as an indirect measure for free T4. A T4/TBG ratio . 17 in a second heel puncture is suggestive of CH-C. Design and methods: In the present study, we evaluated 11 years of Dutch CH NBS us ing a database of referred cases by assessing the contribution of each criterion in the unique s tepwise T4-TSH-TBG NBS algorithm. Results: Between 2007 and the end of 2017, 1 963 465 newborns were scre ened in the Netherlands. Use of the stepwise algorithm led to 3044 referrals and the identification of 612 CH cases, consisting of 496 CH-T, 86 CH-C, and 30 CH of unknown origin diagnoses. We detected 62.8% of CH-C ca ses by the T4/TBG ratio in the second heel puncture. The positive predictive value (PPV) of the stepwise T 4-TSH-TBG NBS algorithm was 21.0%. Conclusion: This evaluation shows that the Dutch stepwise T4-TSH-TBG NBS a lgorithm with a calculated T4/TBG ratio is of great value for the detection of both CH-T and CH-C in the N etherlands, at the cost of a lower PPV compared to TSHbased NBS strategies