Prevalence of FLG loss-of-function mutations R501X, 2282del4, and R2447X in Spanish children with atopic dermatitis.

BACKGROUND/OBJECTIVES: Atopic dermatitis (AD) is the most prevalent inflammatory skin disorder, and is often associated with a personal or family history of atopic disease. The presence of loss-of-function mutations in the filaggrin gene (FLG) is the main predisposing factor for AD FLG mutations show ethnic and geographical variations, even between European populations. We sought to determine the frequency of the 3 most common FLG null mutations in a population of Spanish children consisting of healthy controls and AD patients. We also investigated the association between these 3 FLG mutations and AD. METHODS: A total of 214 participants (111 AD patients and 103 healthy controls) were enrolled in this study. Genotyping for 3 FLG null mutations (R501X, 2282del4, and R2447X) was performed by conventional Sanger sequencing. RESULTS: The combined mutation frequency was 1.9% in the control group and 12.6% in the AD group. The most common FLG mutation in AD patients was R501X (9.9%), followed by R2447X (2.7%) and 2282del4 (1.8%). CONCLUSION: These findings further our understanding of the prevalence of FLG null mutations in the Spanish population, and suggest that the frequency of FLG mutations in AD patients in Spain is slightly higher than that of other Mediterranean countries.

Detecting paraprotein interference on a direct bilirubin assay by reviewing the photometric reaction data.

BACKGROUND: The direct bilirubin (D-Bil) assay on the AU Beckman Coulter instrumentation can be interfered by paraproteins, which may result in spurious D-Bil results. In a previous work, we took advantage of this fact to detect this interference, thus helping with the identification of patients with unsuspected monoclonal gammopathies. In this work, we investigate the possibility to detect interference based on the review of the photometric reactions, regardless of the D-Bil result. METHODS: The D-Bil assay was carried out in a set of 2164 samples. It included a group of 164 samples with paraproteins (67 of which caused interference on the assay), as well as different groups of samples for which high absorbance background readings could also be expected (i.e. hemolyzed, lipemic, or icteric samples). Photometric reaction data were reviewed and receiver operating characteristics (ROC) curves were used to establish a cut-off for absorbance that best discriminates interference. RESULTS: The best cut-off was 0.0100 for the absorbance at the first photometric point of the complementary wavelength in the blank cuvette. Once the optimal cut-off for probable interference was selected, all samples analyzed in our laboratory that provided absorbance values above this cut-off were further investigated to try to discover paraproteins. During a period of 6 months, we detected 44 samples containing paraproteins, five of which belonged to patients with non-diagnosed monoclonal gammopathies. CONCLUSIONS: Review of the photometric reaction data permits the systematic detection of paraprotein interference on the D-Bil AU assay, even for samples for which reasonable results are obtained.

Analytical interference by monoclonal immunoglobulins on the direct bilirubin AU Beckman Coulter assay: the benefit of unsuspected diagnosis from spurious results.

BACKGROUND: Monoclonal (M) components can interfere with the direct bilirubin (D-Bil) assay on the AU Beckman Coulter instrumentation and produce spurious results, such as D-Bil values greater than total bilirubin (T-Bil) or very low/negative D-Bil values. If properly detected, this interference may uncover undiagnosed patients with monoclonal gammopathy (MG). METHODS: We investigated the interference rate on the D-Bil AU assay in serum samples known to contain M proteins along with their isotype and described the protocol set up in our laboratory to help with the diagnosis of MG based on D-Bil spurious results as first indication. RESULTS: During a period of 4 years, 15.4% (345 of 2235) of serum samples containing M immunoglobulins produced erroneous D-Bil results, although no clear relationship between the magnitude or isotype of the M component and interference could be found. In total 22 new patients were diagnosed with MG based on the analytical artefact with the D-Bil as first indication. CONCLUSIONS: The D-Bil interference from MG on the Beckman AU analysers needs to be made known to laboratories in order to prevent clinical confusion and/or additional workup to explain the origin of anomalous results. Although this information may not add to the management of existing patients with serum paraproteins, it can benefit patients that have not been diagnosed with MG by triggering follow up testing to determine if M components are present.

Direct trace-elemental analysis of urine samples by laser ablation-inductively coupled plasma mass spectrometry after sample deposition on clinical filter papers.

Collection of biological fluids on clinical filter papers shows important advantages from a logistic point of view, although analysis of these specimens is far from straightforward. Concerning urine analysis, and particularly when direct trace elemental analysis by laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is aimed at, several problems arise, such as lack of sensitivity or different distribution of the analytes on the filter paper, rendering obtaining reliable quantitative results quite difficult. In this paper, a novel approach for urine collection is proposed, which circumvents many of these problems. This methodology consists on the use of precut filter paper discs where large amounts of sample can be retained upon a single deposition. This provides higher amounts of the target analytes and, thus, sufficient sensitivity, and allows addition of an adequate internal standard at the clinical lab prior to analysis, therefore making it suitable for a strategy based on unsupervised sample collection and ulterior analysis at referral centers. On the basis of this sampling methodology, an analytical method was developed for the direct determination of several elements in urine (Be, Bi, Cd, Co, Cu, Ni, Sb, Sn, Tl, Pb, and V) at the low µg L(-1) level by means of LA-ICPMS. The method developed provides good results in terms of accuracy and LODs (≤1 µg L(-1) for most of the analytes tested), with a precision in the range of 15%, fit-for-purpose for clinical control analysis.

Experience with Cutaneous Manifestations in COVID-19 Patients during the Pandemic.

After the beginning of the SARS-CoV-2 pandemic, our dermatology department created a multidisciplinary unit to manage patients with cutaneous manifestations associated with COVID-19. With the objective of identifying skin lesions in patients with suspected COVID-19 and evaluating possible associations with systemic involvement, other infectious agents and coagulation disorders, we carried out a prospective observational study that included all patients that attended our COVID-19 dermatology clinic with a multidisciplinary protocol. A total of 63 patients (mean 34.6 years) were enrolled between May 2020 and February 2021. Overall, 27 patients (42.9%) had a positive COVID-19 test, and 74.6% had COVID-19 clinical signs. The most common skin lesion was maculopapular rash (36.5%), predominantly seen in male (54.2%) and older patients (42 vs. 30 years), followed by chilblain-like lesions (20.6%) in younger patients (13.9 vs. 20.9 years) who were predominantly barefoot at home (69.2%); these patients exhibited a tendency towards a negative COVID-19 test. A total of 12 patients (19.1%) had positive serology for herpesvirus 6 (IgM or IgG). We conclude that the COVID-19-associated skin lesions we observed were similar to those previously described. Questions as to the underlying mechanisms remain. Interferon, possibly aided by cold exposure, may cause perniosis-like lesions. Other cutaneous manifestations were similar to those caused by other viruses, suggesting that SARS-CoV-2 may reactivate or facilitate other viral infections.

Serum copper concentrations in hospitalized newborns.

BACKGROUND: Low serum Cu and ceruloplasmin (Cp) concentrations in newborns can be the first indication of a severe Cu deficient intake or, alternatively, of genetic diseases affecting Cu metabolism. However, Cu and Cp concentrations can also be influenced by other variables that render their quantitative results difficult to interpret. Therefore, it is necessary to identify these variables and stratify Cu and Cp concentrations according to these altering factors. METHODS: Serum Cu and Cp concentrations for 564 hospitalized newborns (0-12days of life) are stratified according to their age, prematurity (birth weight or gestational age), type of feeding and inflammatory state (assessed by the serum high sensitivity C-reactive protein (hs-CRP) level) to identify potential correlations. RESULTS: Serum Cu and Cp concentrations are influenced by all four variables analyzed, although inflammation is the most significant: the greater the hs-CRP concentration, the greater the serum Cu and Cp concentrations. Prematurity is also an important factor and preterm infants often show very low Cu and Cp concentrations. Age of life and type of feeding have in turn a more modest effect on these magnitudes, being slightly greater at 3-5days of age in breastfed newborns. CONCLUSIONS: Inflammation and prematurity are the main variables affecting serum Cu and Cp concentrations in newborns. Therefore, hs-CRP should always be assayed in parallel to Cu status. When there is an inflammatory state proper interpretation of these concentrations can be challenging.

Serum sample containing endogenous antibodies interfering with multiple hormone immunoassays. Laboratory strategies to detect interference.

OBJECTIVES: Endogenous antibodies (EA) may interfere with immunoassays, causing erroneous results for hormone analyses. As (in most cases) this interference arises from the assay format and most immunoassays, even from different manufacturers, are constructed in a similar way, it is possible for a single type of EA to interfere with different immunoassays. Here we describe the case of a patient whose serum sample contains EA that interfere several hormones tests. We also discuss the strategies deployed to detect interference. SUBJECTS AND METHODS: Over a period of four years, a 30-year-old man was subjected to a plethora of laboratory and imaging diagnostic procedures as a consequence of elevated hormone results, mainly of pituitary origin, which did not correlate with the overall clinical picture. RESULTS: Once analytical interference was suspected, the best laboratory approaches to investigate it were sample reanalysis on an alternative platform and sample incubation with antibody blocking tubes. Construction of an in-house 'nonsense' sandwich assay was also a valuable strategy to confirm interference. In contrast, serial sample dilutions were of no value in our case, while polyethylene glycol (PEG) precipitation gave inconclusive results, probably due to the use of inappropriate PEG concentrations for several of the tests assayed. CONCLUSIONS: Clinicians and laboratorians must be aware of the drawbacks of immunometric assays, and alert to the possibility of EA interference when results do not fit the clinical pattern.

Lead screening in DBS by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry: application to newborns and pregnant women.

BACKGROUND: DBS have become a clinical specimen especially adequate for establishing home-based collection protocols. In this work, high-resolution continuum source graphite furnace atomic absorption spectrometry is evaluated for the direct monitoring of Pb in DBS, both as a quantitative tool and a screening method. METHODOLOGY: The development of the screening model is based on the establishment of the unreliability region around the threshold limits, 100 or 50 µg l(-1). More than 500 samples were analyzed to validate the model. CONCLUSION: The screening method demonstrated high sensitivity (the rate of true positives detected was always higher than 95%), an excellent LOD (1 µg l(-1)) and high throughput (10 min per sample).

Birth Prevalence of Fatty Acid ß-Oxidation Disorders in Iberia.

Mitochondrial fatty acid ß-oxidation disorders (FAOD) are main targets for newborn screening (NBS) programs, which are excellent data sources for accurate estimations of disease birth prevalence. Epidemiological data is of key importance for the understanding of the natural history of the disorders as well as to define more effective public health strategies. In order to estimate FAOD birth prevalence in Iberia, the authors collected data from six NBS programs from Portugal and Spain, encompassing the screening of more than 1.6 million newborns by tandem mass spectrometry (MS/MS), and compared it with available data from other populations. The participating NBS programs are responsible for the screening of about 46% of all Iberian newborns. Data reveals that Iberia has one of the highest FAOD prevalence in Europe (1:7,914) and that Portugal has the highest birth prevalence of FAOD reported so far (1:6,351), strongly influenced by the high prevalence of medium-chain acyl-CoA dehydrogenase deficiency (MCADD; 1:8,380), one of the highest ever reported. This is justified by the fact that more than 90% of Portuguese MCADD patients are of Gypsy origin, a community characterized by a high degree of consanguinity. From the comparative analysis of various populations with comparable data other differences emerge, which points to the existence of significant variations in FAOD prevalences among different populations, but without any clear European variation pattern. Considering that FAOD are one of the justifications for MS/MS NBS, the now estimated birth prevalences stress the need to screen all Iberian newborns for this group of inherited metabolic disorders.

Utilidad de la determinación de cobre en periodo neonatal. Enfermedad de Menkes / Usefulness of Cu determination in the neonatal period. Menkes disease

Bajas concentraciones séricas de Cu en neonatos pueden ser la primera señal de una ingesta deficiente de este elemento o, alternativamente, de enfermedades genéticas que afectan su metabolismo. Desgraciadamente, es difícil la interpretación de las concentraciones de Cu en esta población, ya que están influenciadas por distintos factores, entre ellos la prematuridad, el tipo de alimentación y la presencia de un estado inflamatorio. Sin embargo, en el caso que aquí se describe fue la baja concentración sérica de Cu la primera pista para el diagnóstico de enfermedad de Menkes. Se demuestra así la utilidad de la determinación de Cu dentro de protocolos neurometabólicos y de retraso psicomotor en población neonatal y lactante (AU)

Low serum Cu concentrations in newborns can be the first indication of a severe Cu deficient intake or, alternatively, of genetic diseases affecting Cu metabolism. Unfortunately, interpretation of serum Cu concentrations in this population is difficult because they also influenced by several variables, such as, prematurity, type of feeding and inflammatory conditions. However, in the case described in this paper was a low serum Cu concentration the first clue for diagnosing Menkes disease. It is so demonstrated the usefulness of Cu determination within neurometabolic or psychomotor retardation protocols for newborn and infant populations (AU)