A three-step molecular protocol employing DNA obtained from dried blood spots for neonatal screening for 45,X Turner syndrome.
Turner syndrome (TS) is one of the most common human chromosomal abnormalities; it is characterized by the presence of one normal X chromosome and the complete or partial loss of the second X chromosome. The early recognition of TS patients allows for adequate therapy for short stature and pubertal sex steroid substitution. We developed a cost-effective molecular diagnostic tool that can be used to identify 45,X TS patients from dried blood spots, for possible use in neonatal screening for TS. We used a three-step method for 45,X TS detection: i) DNA extraction from dried blood spot samples, ii) pre-PCR HpaII digestion (methylation-sensitive enzyme) and iii) GeneScan analysis of selected cases. DAX-1 gene amplification was used to recognize DNA integrity, and the androgen receptor gene (Xq11-12), which is both a highly polymorphic and methylated gene, was used to determine the number of X chromosome alleles. Using this three-step diagnostic procedure, we detected apparent TS in 1/304 (0.33%) samples; such individuals should be submitted to clinical examination and karyotype confirmation. The three-step 45,X TS neonatal screening protocol is a simple, reliable, fast (under 30 h) and cost-effective diagnostic tool, useful for the neonatal detection of TS.
Laboratório de Medicina Molecular, Departamento de Ciências Fisiológicas e Puericultura, Faculdade de Ciências Médicas da Santa Casa de São Paulo, São Paulo, SP, Brasil. mylene.rocha@fcmscsp.edu.br
Mylene Neves
MN
Rocha
Murilo Rezende
MR
Melo
Carlos Alberto
CA
Longui
Daniela Vilariço Alves
DV
de Oliveira
Carolina Costa
CC
Figueiredo
Paulo Roberto
PR
Pacchi
D001800:Blood Specimen Collection; D003362:Cost-Benefit Analysis; D004247:DNA / Q000032:analysis* / Q000097:blood; D019175:DNA Methylation; D005260:Female; D005820:Genetic Testing / Q000191:economics / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening / Q000191:economics / Q000379:methods*; D016133:Polymerase Chain Reaction; D011944:Receptors, Androgen / Q000235:genetics; D014424:Turner Syndrome / Q000175:diagnosis* / Q000235:genetics
D011944:Receptors, Androgen; D004247:DNA