[Clinical implementation of non-invasive prenatal study for detecting aneuploidies by fetal DNA based on single nucleotide polymorphisms: two years in Mexico]. / Implementación clínica del estudio prenatal no invasivo para Ia detección de aneuplodías mediante ADN fetal con base en polimorfismos de nucleótido único: dos años en México.

BACKGROUND: Recent data have shown that non invasive prenatal test (NIPT) for the detection of fetal aneuploidies (chromosomes 13, 18, 21, X, Y, and triploidy) by cell free fetal DNA in maternal blood (cfDNA) is a clinical reality, with detection rates > 99% and false positive rates of 0.1%. Results that exceed the first trimester screening. OBJECTIVE: To describe our experience of 2 years integrating NIPT by cfADN in its variant of single nucleotide polymorphism (SNPs) as a screening method for the detection of common aneuploidies, since nine weeks of gestation. PATIENTS AND METHODS: Observational prospective study from March 2013 to February 2015. Women with a singleton pregnancy were offered conventional prenatal screening fetal aneuploidy and or new alternative NIPT-SNPs. RESULTS: 270 women were included,the mean maternal age was 35.3 years with a mean gestational age of 11.85 weeks. The result was obtained in 98.5%, with an average report time of 7.5 working days. Blood collection was repeated in fifteen patients, obtaining the result in eleven. The NIPT tested positive for ten cases, 8 for trisomy 21, one for trisomy 18 and one trisomy 13. CONCLUSIONS: We describe our first two years of integrating NIPT-SNPs to obstetric private practice, that is an alternative screening with the potential to be incorporated into theexisting algorithms in prenatal care, from the ninth week of gestation. We expect this information will motivate a debate on the issue of prenatal screening and get to improve obstetric care and genetic counseling in Mexico.

[Prevalence of chromosomal alterations in infertile patients studied in a clinic of assisted reproduction]. / Prevalencia de alteraciones cromosómicas en pacientes infértiles estudiadas en una clínica de reproducción asistida.

BACKGROUND: Chromosomal abnormalities are a frequent cause of infertility. There is not consensus if should be included in the work-up of infertile couple. OBJECTIVE: to evaluate the prevalence of chromosomal abnormalities in our population of infertile couple and support the cytogenetic exam in the initial protocol. PATIENTS AND METHODS: Retrospective study of 787 infertile patients divided in five groups, to whom a cytogenetic exam was performed between January 2004 and April 2007. RESULTS: The prevalence of general chromosomal abnormalities was 12.5% (98/787). We found a 14.8% (34/229) with severe male factor, 14.3% (2/14) with premature ovarian failure, 12.3% (20/162) with recurrent pregnancy loss, 8% (9/112) idiopathic infertility and 12.2% (33/270) associated with other causes. The major alterations correspond to trisomies, translocations, and 9 chromosome markers. CONCLUSIONS: The results of this study are consistent with those reported in the literature which are associated with a greater prevalence of chromosomal abnormalities in infertile couples compared with the general population, this findings show the importance of consider the cytogenetic study in the initial diagnosis protocol of infertile couple.