RESUMO
Aims: To explore the feasibility of detecting sex chromosome aneuploidies (SCAs) by means of gene copy number quantification of short stature homeobox (SHOX), vesicle-associated membrane protein 7 (VAMP7), and SRY in newborns. Materials and Methods: Gene doses of SHOX, VAMP7, and SRY were determined by quantitative polymerase chain reaction (qPCR) using DNA obtained from dried blood samples from newborns. Relative quantification values were obtained. An aneuploidy profile was established according to cutoff values. Samples with ≥2 gene doses (out of range) were reanalyzed, and those with aneuploidy profiles were confirmed by karyotyping. Sensitivity, specificity, and positive and negative predictive values were obtained. Results: A total of 10,033 samples were collected (4945 females and 5088 males). Of 244 (2.43%) samples with ≥2 gene doses that were retested, 20 cases were confirmed. The overall incidence of SCAs was 1 in 500 live newborns. There were six cases of Turner syndrome (1/824), 3 cases of XXX (1/1648), 7 cases of Klinefelter syndrome (1/726), and 4 cases of of XYY (1/1272). The sensitivity was 0.952 (95.42%); the specificity was 0.975 (97.56%); the positive predictive value was 0.909 (90.91%) and the negative predictive value was 0.987 (98.77%). Conclusions: Gene copy number analyses of the VAMP7, SHOX, and SRY genes by qPCR from blood samples spotted onto filter paper is a highly reliable method for the early detection of male and female SCAs.
Assuntos
Triagem Neonatal/métodos , Transtornos do Cromossomo Sexual no Desenvolvimento Sexual/diagnóstico , Transtornos do Cromossomo Sexual no Desenvolvimento Sexual/genética , Aneuploidia , Cromossomos Humanos X , Variações do Número de Cópias de DNA/genética , Feminino , Dosagem de Genes , Humanos , Recém-Nascido , Cariotipagem/métodos , Síndrome de Klinefelter/diagnóstico , Masculino , México , Diagnóstico Pré-Natal/métodos , Proteínas R-SNARE/genética , Aberrações dos Cromossomos Sexuais , Cromossomos Sexuais/genética , Proteína da Região Y Determinante do Sexo/genética , Proteína de Homoeobox de Baixa Estatura/genética , Trissomia/diagnóstico , Síndrome de Turner/diagnósticoRESUMO
INTRODUCTION: Prenatal diagnosis of Down syndrome (DS) is based on the calculated risk of maternal age, biochemical and ultrasonographic markers and recently by cfDNA. Differences in proteomic profiles may give an opportunity to find new biomarkers. OBJECTIVE: Characterize proteome of serum of mothers carrying DS fetus. MATERIAL AND METHODS: Blood serum samples of three groups of women were obtained, (a) 10 non-pregnant, (b) 10 pregnant with healthy fetus by ultrasound evaluation, (c) nine pregnant with DS fetus. Sample preparation was as follows: Albumin/IgG depletion, desalting, and trypsin digestion; the process was performed in nanoUPLC MS/MS. Data analysis was made with Mass Lynx 4.1 and ProteinLynx Global Server 3.0, peptide and protein recognition by MASCOT algorithm and UNIPROT-Swissprot database. RESULTS: Each group showed different protein profiles. Some proteins were shared between groups. Only sera from pregnant women showed proteins related to immune and clot pathways. Mothers with DS fetus had 42 specific proteins. CONCLUSIONS: We found a different serum protein profile in mothers carrying DS fetuses that do not reflect expression of genes in the extra chromosome. Further studies will be necessary to establish the role of these proteins in aneuploid fetus and analyze their possible use as potential biomarkers.
