Objectives This paper reports early screening results from the newborn sickle cell disease screening programme recently implemented in England. Setting England. Screening is offered at 5-8 days of age as part of the existing bloodspot test and offered to all babies irrespective of ethnicity. Methods The laboratory methods recommended are high performance liquid chromatography (HPLC) and iso-electric focusing (IEF). 15 Two methods of analysis must be applied to all screen positive results. The conditions screened for are:- Sickle cell anaemia (Hb SS), Hb SC disease, Hb S/β-thalassaemia, Hb S/DPunjab, Hb S/OArab, Hb S/HPFH. Carriers identified for the common haemoglobin variants are reported to parents and follow-up counselling is offered. A bespoke laboratory quality assurance programme has been established which has defined standards of satifactory performance. Results Provisional figures from the first seven months of screening (up to March 2004) 108,255 infants were screened gave a screen positive rate of 1:900 for these high prevalence areas and a carrier rate of 2.7%. Figures for 2004-2005 show about 250 significant screen positive results for sickle cell disorders and about 6,500 carriers were identified. The birth prevalence for screen positive results from 2004-05 is 1:1500. We estimate that when there is countrywide data, the national birth prevalence will be about 1:2000-1:2,500. Conclusion The results from the national newborn sickle cell screening programme in England - show that the sickle cell disorders are as common as cystic fibrosis (CF) in England, although the distribution of cases is concentrated in London and other urban areas. The findings and approach to implementation adopted in England may be of interest to other Western European countries with increasing rates of sickle cell disease who are considering such programmes and also to other developed countries.
Aim: There are limited published data on the performance of the percentage of haemoglobin A (Hb A) as a screening test for beta thalassaemia major in the newborn period. This paper aims to analyse data derived from a national newborn bloodspot screening programme for sickle cell disease on the performance of haemoglobin A (Hb A) as a screening test for beta thalassaemia major in the newborn period. Methods: Newborn bloodspot sickle cell screening data from 2,288,008 babies were analysed. Data reported to the NHS Sickle Cell and Thalassaemia Screening Programme in England for the period 2005 to 2012 were also reviewed to identify any missed cases (4,599,849 babies). Results: Within the cohort of 2,288,008 births, 170 babies were identified as screen positive for beta thalassaemia major using a cut-point of 1.5% HbA. There were 51 identified through look-back methods and 119 prospectively identified from 4 screening laboratories. Among 119 babies with prospective data, 7 were lost to follow up and 15 were false positive results. Using a cutoff value of 1.5% Hb A as a percentage of the total haemoglobin as a screening test for beta thalassaemia major in the newborn provides an estimated sensitivity of 99% (from the look back arm of the study) with a positive predictive value of 87% (from the prospective arm of the study). Excluding infants born before 32 weeks gestation, the positive predictive value rose to 95%. Conclusion: A haemoglobin A value of less than 1.5% is a reliable screening test for beta thalassaemia major in the newborn period.
Splenectomy was not clearly beneficial and may have contributed to the development of pulmonary hypertension. The case favors a cautious approach when considering splenectomy for patients with Hb Taybe.
A novel beta chain variant found in combination with beta(0)-thalassemia (thal) was identified in a male infant by electrospray ionization mass spectrometry (ESI-MS). Analysis of the infant's denatured blood and a 30 min. tryptic digest of his blood identified the mutation as beta56(D7)Gly-->Cys, which was confirmed by tandem mass spectrometry (MS/MS). We have named this new variant Hb Leeds. The infant's parents, resident in Yorkshire, UK, but originally from Pakistan, were found to have beta(0)-thalassemia (thal) trait (mother) and Hb Leeds trait (father). Hematological data on the infant's parents and siblings are given. Hb Leeds trait was also found in three unrelated Pakistani adults living in the same area of Yorkshire. Hb Leeds trait in adults appears to have few clinical manifestations, but when combined with beta(0)-thal it led to a more severe anemia in the infant than in the corresponding thalassemic trait in his mother.
Currently, newborn haemoglobinopathy screening is carried out using HPLC or isoelectric focusing (IEF). We have previously described a rapid and specific electrospray mass spectrometry–mass spectrometry (MSMS) technique, using multiple reaction monitoring (MRM) based peptide analysis, for simultaneous detection of the clinically significant haemoglobinpathies; haemoglobin (Hb)S, HbC, HbE, HbDPunjab and HbOArab. Here we report the results of a comparison of 40,000 newborn blood spots screened by both IEF and MSMS. For both IEF and MSMS analysis, blood spots (3.2mm) were punched into separate 96 well plates. IEF was performed using the Resolve haemoglobin test kit (PerkinElmer Life Sciences, Waltham, USA) and Isoscan imaging system. For MSMS analysis, the blood spots were digested for 30min at 37°C with a trypsin reagent, and diluted in mobile phase (acetonitrile: water, 50:50, with 0.025% formic acid. Sample, 2μl, was injected directly into the mobile phase (flow rate 80μl/min) and analysed, in positive ion mode, using a Sciex API4000 (Applied Biosystems, Warrington, UK). Specific MRM transitions for HbS, HbC, HbE, HbDPunjab, HbOArab, normal beta, alpha, gamma and delta chains were acquired; total acquisition time per sample was 60 sec. This enabled identification of sickling disorders and thalassaemia major, as well as assessment of transfusion state and potential identification of HbLepore and HbBarts. 40,000 blood spot samples for routine newborn haemoglobinopathy screening were analysed in parallel. HbS was detected in 199 samples; 8 were HbS/HbF only and 3 HbSC. HbC was detected in 39 samples, HbDPunjab in 52, HbE in 48. No HbOArab or HbLepore mutations were detected by either method. There have been no discrepancies between the analytical techniques. Using MSMS, mutation positive samples can be re-run in product ion scan mode to provide peptide sequence and hence unequivocal confirmation of the haemoglobin variant. In addition, 5,000 samples were analysed on a Sciex API4000 Q trap; using the information dependent acquisition facility provided “real time” peptide sequencing thus removing the requirement for re-injection. Sample preparation is very quick and simple for both methods, but the consumable costs associated with the MSMS technique are <10% of those for IEF. The capital cost of MSMS can be offset by high throughput and/or integration with current inherited metabolic disease screening by MSMS. The specificity of the MSMS analysis implies that haemoglobinopathy detection can be limited to specified conditions, based on agreed screening policy, and can eliminate the need for costly and time consuming second line testing. This study demonstrates that newborn haemoglobinopathy screening can be carried out rapidly, easily, and cost effectively using MSMS technology. It enables rationalisation of technology platforms in newborn screening by consolidating screening for haemoglobinopathies and inherited metabolic diseases onto MSMS.
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