Severe combined immunodeficiency (SCID), the most severe form of T-cell immunodeficiency, can be screened at birth by quantifying T-cell receptor excision circles (TRECs) in dried blood spot (DBS) ...samples. Early detection of this condition speeds up the establishment of appropriate treatment and increases the patient's life expectancy. Newborn screening for SCID started in January 2017 in Catalonia, the first Spanish and European region to universally include this testing. The results obtained in the first 2 years of experience are evaluated here. All babies born between January 2017 and December 2018 were screened. TREC quantification in DBS (1.5 mm diameter) was performed with the Enlite Neonatal TREC kit from PerkinElmer (Turku, Finland). In 2018, the retest cutoff in the detection algorithm was updated based on the experience gained in the first year, and changed from 34 to 24 copies/μL. This decreased the retest rate from 3.34 to 1.4% (global retest rate, 2.4%), with a requested second sample rate of 0.23% and a positive detection rate of 0.02%. Lymphocyte phenotype (T, B, NK populations), expression of CD45RA/RO isoforms, percentage and intensity of TCR αβ and TCR γδ, presence of HLA-DR+ T lymphocytes, and
lymphocyte proliferation were studied in all patients by flow cytometry. Of 130,903 newborns screened, 30 tested positive, 15 of which were male. During the study period, one patient was diagnosed with SCID: incidence, 1 in 130,903 births in Catalonia. Thirteen patients had clinically significant T-cell lymphopenia (non-SCID) with an incidence of 1 in 10,069 newborns (43% of positive detections). Nine patients were considered false-positive cases because of an initially normal lymphocyte count with normalization of TRECs between 3 and 6 months of life, four infants had transient lymphopenia due to an initially low lymphocyte count with recovery in the following months, and three patients are still under study. The results obtained provide further evidence of the benefits of including this disease in newborn screening programs. Longer follow-up is needed to define the exact incidence of SCID in Catalonia.
The gold-standard diagnostic test for peroxisomal disorders (PDs) is plasma concentration analysis of very long-chain fatty acids (VLCFAs). However, this method’s time-consuming nature and ...limitations in cases which present normal VLCFA levels necessitates alternative approaches. The analysis of C26:0-lysophosphatydylcholine (C26:0-LPC) in dried blood spot samples by tandem-mass spectrometry (MS/MS) has successfully been implemented in certain newborn screening programs to diagnose X-linked adrenoleukodystrophy (ALD). However, the diagnostic potential of very long-chain LPCs concentrations in plasma remains poorly understood. This study sought to evaluate the diagnostic performance of C26:0-LPC and other very long-chain LPCs, comparing them to VLCFA analysis in plasma. The study, which included 330 individuals affected by a peroxisomal β-oxidation deficiency and 407 control individuals, revealed that C26:0- and C24:0-LPC concentrations demonstrated the highest diagnostic accuracy (98.8% and 98.4%, respectively), outperforming VLCFA when C26:0/C22:0 and C24:0/C22:0 ratios were combined (98.1%). Combining C24:0- and C26:0-LPC gave the highest sensitivity (99.7%), with ALD females exhibiting notably higher sensitivity compared with the VLCFA ratio combination (98.7% vs. 93.5%, respectively). In contrast, C22:0-LPC exhibited suboptimal performance, primarily due to its low sensitivity (75%), but we identified a potential use to help distinguish between ALD and Zellweger spectrum disorders. In summary, MS/MS analysis of plasma C24:0- and C26:0-LPC concentrations represents a rapid and straightforward approach to diagnose PDs, demonstrating superior diagnostic accuracy, particularly in ALD females, compared with conventional VLCFA biomarkers. We strongly recommend integrating very-long chain LPC plasma analysis in the diagnostic evaluation of individuals suspected of having a PD.
Anti-Kell alloimmunisation is a potentially severe minor blood group type incompatibility, not only as a cause of haemolytic disease of the foetus and newborn, but also due to the destruction of red ...blood cells (RBC) and mature form in the bone marrow with the subsequent hyporegenerative anaemia. In severe cases and when the foetus shows signs of anaemia, an intrauterine transfusion (IUT) may be necessary. When repeated, this treatment can suppress erythropoiesis and worsen the anaemia. We report the case of a newborn who required four IUTs plus an additional RBC transfusion at one month of life due to late onset anaemia. The identification of an adult haemoglobin profile with a complete absence of foetal haemoglobin in the patient's newborn screening samples at 2 and 10 days of life warned us of a possible late anaemia. The newborn was successfully treated with transfusion, oral supplements and subcutaneous erythropoietin. A blood sample taken at 4 months of life showed the expected haemoglobin profile for that age with a foetal haemoglobin of 17.7%. This case illustrates the importance of a close follow-up of these patients, as well as the usefulness of the haemoglobin profile screening as a tool for anaemia assessment.
Purine nucleoside phosphorylase (PNP) deficiency is a rare inherited disorder, resulting in severe combined immunodeficiency. To date, PNP deficiency has been detected in newborn screening only ...through the use of liquid chromatography tandem mass spectrometry. We report the first case in which PNP deficiency was detected by TREC analysis.
Newborn Screening for SCID: Experience in Spain (Catalonia) Argudo-Ramírez, Ana; Martín-Nalda, Andrea; González de Aledo-Castillo, Jose Manuel ...
International journal of neonatal screening,
07/2021, Letnik:
7, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Newborn screening (NBS) for severe combined immunodeficiency (SCID) started in Catalonia in January-2017, being the first Spanish and European region to universally include this testing. In Spain, a ...pilot study with 5000 samples was carried out in Seville in 2014; also, a research project with about 35,000 newborns will be carried out in 2021–2022 in the NBS laboratory of Eastern Andalusia. At present, the inclusion of SCID is being evaluated in Spain. The results obtained in the first three and a half years of experience in Catalonia are presented here. All babies born between January-2017 and June-2020 were screened through TREC-quantification in DBS with the Enlite Neonatal TREC-kit from PerkinElmer. A total of 222,857 newborns were screened, of which 48 tested positive. During the study period, three patients were diagnosed with SCID: an incidence of 1 in 74,187 newborns; 17 patients had clinically significant T-cell lymphopenia (non-SCID) with an incidence of 1 in 13,109 newborns who also benefited from the NBS program. The results obtained provide further evidence of the benefits of early diagnosis and curative treatment to justify the inclusion of this disease in NBS programs. A national NBS program is needed, also to define the exact SCID incidence in Spain.
Acylcarnitine and amino acid analyses of dried blood spot (DBS) samples using tandem mass spectrometry in newborn screening (NBS) programmes can generate false positive (FP) results. Therefore, ...implementation of second-tier tests (2TTs) using DBS samples has become increasingly important to avoid FPs. The most widely used 2TT metabolites include methylmalonic acid, 3-hydroxypropionic acid, methylcitric acid, and homocysteine.
We simultaneously measured 46 underivatised metabolites, including organic acids, acylglycine and acylcarnitine isomers, homocysteine, and orotic acid, in DBS samples using tandem mass spectrometry. To validate this method, we analysed samples from 147 healthy newborns, 160 patients with genetic disorders diagnosed via NBS, 20 patients with acquired vitamin B12 deficiency, 10 newborns receiving antibiotic treatment, and nine external quality control samples.
The validation study revealed that 31 metabolites showed good analytical performance. Furthermore, this method detected key metabolites for all diseases associated with increased levels of the following acylcarnitines: C3, C4, C5, C4DC/C5OH, and C5DC. The sensitivity of this method to detect all diseases was 100 %, and the specificity was 74-99 %, except for glutaric aciduria type 1. This method can also be used to diagnose mitochondrial fatty acid β-oxidation disorders (FAODs) and urea cycle defects (UCDs).
We have described a 2TT panel of 31 metabolites in DBS samples based on an easy and rapid method without derivatisation. Its implementation allowed us to distinguish between different organic acidurias, some FAODs, and UCDs. This new strategy has increased the efficiency of our NBS programme by reducing FP and false negative results, second sample requests, and the time required for diagnosis.
Background
The current scenario of newborn screening is changing as DNA studies are being included in the programs of several countries. Severe combined immunodeficiency (SCID) disorders can be ...detected using quantitative PCR assays to measure T‐cell receptor excision circles (TRECs), a byproduct of correct T‐cell development. However, in addition to SCID, other T‐cell‐deficient phenotypes such as 22q11.2 deletion syndrome 22q11.2 duplication syndrome, CHARGE syndrome, and trisomy 21 are detected.
Methods
We present our experience with the detection of 22q11.2 deletion syndrome and 22q11.2 duplication syndrome in a series of 103,903 newborns included in the newborn screening program of Catalonia (Spain).
Results
Thirty newborns tested were positive (low TREC levels) and five were found to have copy number variations at the 22q11 region (4 deletions and 1 duplication) when investigated with array comparative genomic hybridization technology and MLPA.
Conclusion
Newborn screening for SCID enables detection of several conditions, such as 22q syndromes, which should be managed by prompt, proactive approaches with adequate counseling for families by a multidisciplinary team.
Newborn screening (NBS) using T‐cell receptor excision circle (TREC) assays to detect severe combined immunodeficiency (SCID) has been established in several geographic areas. In addition to SCID, other T‐cell deficient conditions, such as 22q11.2 deletion syndrome (DS), CHARGE syndrome, and trisomy 21, can also be detected through NBS. An early diagnosis of 22q11.2 DS is associated with a better clinical outcome, mainly because of the possibility of early protocolled care, including rehabilitation and adapted school programs, an appropriate vaccination schedule, and adequate genetic counseling.
To ensure the quality of the new-born screening (NBS), our laboratory reviewed the analytical procedure to detect subjective steps that may represent a risk to the patient. Two subjective activities ...were identified in the extra-analytical phases: the classification of dried blood spots (DBS) according to their quality and the assignment of haemoglobin patterns. To keep these activities under control, inter-rater studies were implemented. This study aimed to evaluate the inter-rater reliability and the effectiveness of the measures taken to improve the agreement between observers, to assure NBS results' quality.
Dried blood spots specimens were used for the inter-rater studies. Ten studies were performed to assess DBS quality classification, and four to assess the assignment of haemoglobin patterns. Krippendorff's alpha test was used to estimate inter-rater reliability. Causes were investigated when alpha values were below 0.80.
For both activities, the reliability obtained in the first studies was inadequate. After investigation, we detected that the criterion to classify a DBS as scant was not consolidated, and also a lack of consensus on whether or not to report Bart's haemoglobin depending on its percentage. Alpha estimates became higher once the training was reinforced and a consensus about the appropriate criteria to be applied was reached.
Inter-rater reliability assessment helped us to ensure the quality of subjective activities that could add variability to NBS results. Furthermore, the evolution of the alpha value over time allowed us to verify the effectiveness of the measures adopted.
Background Continued dietary treatment since early diagnosis through newborn screening programs usually prevents brain-related complications in phenylketonuria (PKU). However, subtle neurocognitive ...and brain alterations may be observed in some adult patients despite early treatment. Nevertheless, neuropsychological and neuroimaging studies in the field remain scarce. Objectives This work aimed to determine possible neuropsychological and structural brain alterations in treated adult patients with PKU. Methods Thirty-five patients with PKU and 22 healthy controls (HC) underwent neuropsychological assessment and T1-weighted magnetic resonance imaging on a 3 T scanner. FreeSurfer (v.7.1) was used to obtain volumetric measures and SPSS (v27.0.1.0) was used to analyze sociodemographic, neuropsychological, volumetric, and clinical data (p < 0.05). Results Adult patients with PKU showed significantly lower performance than HC in Full Scale IQ (t = 2.67; p = .010) from the WAIS-IV. The PKU group also showed significantly lower volumes than HC in the pallidum (U = 224.000; p = .008), hippocampus (U = 243.000; p = .020), amygdala (U = 200.000; p = .002), and brainstem (t = 3.17; p = .006) as well as in total cerebral white matter volume (U = 175.000; p = .001). Blood phenylalanine (Phe) levels in PKU patients were negatively correlated with the pallidum (r = -0.417; p = .013) and brainstem (r = -0.455, p = .006) volumes. Conclusions Adult patients with early-treated PKU showed significantly lower global intelligence than HC. Moreover, these patients showed reduced global white matter volume as well as reductions in the volume of several subcortical grey matter structures, which might be related to the existence of underlying neurodevelopmental alterations. Higher blood Phe levels were also negatively correlated with pallidum and brainstem, suggesting a higher vulnerability of these structures to Phe toxicity. Keywords: Phenylketonuria, Adult early-treated patients, Blood phenylalanine levels, Neuroimaging, Volumetry, Neuropsychological assessment
Background: Newborn screening programmes
(NBSP) have experienced a qualitative breakthrough
due to the implementation of tandem mass spectrometry.
However, the tests used give rise to false positives ...(FP)
generating an excessive request for second samples with
the consequent anxiety of the families. In order to avoid this
problem several programmes have developed second-tier
tests (2TT).
Methods: This article presents our experience in the
implementation of 2TT in the NBSP of Catalonia, as well
as in other international programmes.
Results: From 2004 to the present, 2TT tests have been
developed for more than 30 diseases. The use of 2TT helps
to decrease the FP rate and increase the positive predictive
value (PPV). In the NBSP of Catalonia, the implementation
of 2TT for the detection of methylmalonic and propionic
acidemias, homocystinurias, maple syrup disease and citrulinaemia,
has managed to increase the PPV to 95% and decrease
the PF rate to less than 0.01%. In cystic fibrosis, the
application of 2TT slightly increases PPV but with a significant
decrease in the request for second samples and in the
number of cases referred to clinical units.
Conclusions: The introduction of 2TT in the NBSP
allows to reduce considerably the FP, decreases the number
of requested samples, as well as both anxiety and stress
of the families, at the same time that the hospital costs are
reduced and the PPV is increased, improving notably the
efficiency of the NBSP.
Fundamentos: Los programas de cribado neonatal
(PCN) han experimentado un gran avance cualitativo debido
a la implementación de la espectrometría de masas en
tándem. Sin embargo, las pruebas utilizadas dan lugar a falsos
positivos (FP) generando una excesiva solicitud de segundas
muestras con la consiguiente ansiedad de las familias.
Con el fin de evitar este problema diversos programas
han desarrollado pruebas de segundo nivel (2TT).
Métodos: En este artículo se presenta nuestra experiencia
en la implementación de 2TT en el PCN de
Cataluña, así como en otros programas internacionales.
Resultados: Desde el año 2004 hasta la actualidad
se han desarrollado pruebas de 2TT para más de 30 enfermedades.
La utilización de 2TT ayuda a disminuir la tasa
de FP y aumentar el valor predictivo positivo (VPP). En el
PCN de Cataluña, la implementación de 2TT para la detección
de acidemias metilmalónicas y propiónica, homocistinurias,
jarabe de arce y citrulinemia, ha conseguido aumentar
el VPP a un 95% y disminuir la tasa de FP a menos del
0,01%. En la fibrosis quística la aplicación de 2TT aumenta
ligeramente el VPP pero con disminución significativa de
la solicitud de segundas muestras y de los casos referidos a
las unidades clínicas.
Conclusiones: La introducción de los 2TT en los
PCN permite reducir considerablemente los FP, disminuye
el número de muestras solicitadas, así como la ansiedad y
el estrés de las familias, a la vez que se reducen los costes
hospitalarios y se aumenta el VPP, mejorando notablemente
la eficiencia de los PCN.
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