ABSTRACT
OBJECTIVE: To analyze the fetal fraction, fetal sex, and chromosomal aneuploidy in multiple pregnancies using noninvasive prenatal testing (NIPT). METHOD: A total of 362 pregnant women including 203 singleton pregnancies, 69 twins, and 90 higher-order multiple pregnancies were recruited. Fetal fractions estimated by size ratio-based and Y chromosome-based approaches in singleton pregnancies with male fetus were used as source data to establish the model. The model was then applied to multiple pregnancies for fetal fraction estimation. By comparing the fetal fractions estimated by size ratio to those estimated by Y chromosome or autosomal chromosomes, fetal sex and chromosomal aneuploidy can be analyzed. RESULTS: The size ratio-based approach has been well established in estimating fetal fractions for twin and higher-order multiple pregnancies. Fetal fraction had a positive correlation with gestational age in twin and triplet pregnancies. Fetal sex was determined with accuracies of 98.6% (95% CI, 92.19%-99.96%) in twins and 97.6% (95% CI, 91.76%-99.71%) in triplet pregnancies. Four trisomy 21, one trisomy 18, and one trisomy 13 cases were detected by NIPT. Two trisomy 21 singleton pregnancies and one trisomy 21 twin pregnancy were confirmed by karyotyping. CONCLUSION: Fetal sex and chromosomal aneuploidy in multiple pregnancies can be determined using NIPT.
Subject(s)
Aneuploidy , Cell-Free Nucleic Acids/analysis , Noninvasive Prenatal Testing , Pregnancy, Multiple , Adolescent , Adult , Female , Gestational Age , Humans , Middle Aged , Pregnancy , Sex Determination Analysis , Young AdultABSTRACT
A novel Ebola virus (EBOV) first identified in March 2014 has infected more than 25,000 people in West Africa, resulting in more than 10,000 deaths. Preliminary analyses of genome sequences of 81 EBOV collected from March to June 2014 from Guinea and Sierra Leone suggest that the 2014 EBOV originated from an independent transmission event from its natural reservoir followed by sustained human-to-human infections. It has been reported that the EBOV genome variation might have an effect on the efficacy of sequence-based virus detection and candidate therapeutics. However, only limited viral information has been available since July 2014, when the outbreak entered a rapid growth phase. Here we describe 175 full-length EBOV genome sequences from five severely stricken districts in Sierra Leone from 28 September to 11 November 2014. We found that the 2014 EBOV has become more phylogenetically and genetically diverse from July to November 2014, characterized by the emergence of multiple novel lineages. The substitution rate for the 2014 EBOV was estimated to be 1.23 × 10(-3) substitutions per site per year (95% highest posterior density interval, 1.04 × 10(-3) to 1.41 × 10(-3) substitutions per site per year), approximating to that observed between previous EBOV outbreaks. The sharp increase in genetic diversity of the 2014 EBOV warrants extensive EBOV surveillance in Sierra Leone, Guinea and Liberia to better understand the viral evolution and transmission dynamics of the ongoing outbreak. These data will facilitate the international efforts to develop vaccines and therapeutics.
Subject(s)
Ebolavirus/genetics , Evolution, Molecular , Genetic Variation/genetics , Hemorrhagic Fever, Ebola/epidemiology , Hemorrhagic Fever, Ebola/virology , Base Sequence , Disease Outbreaks/statistics & numerical data , Ebolavirus/isolation & purification , Epidemiological Monitoring , Genome, Viral/genetics , Hemorrhagic Fever, Ebola/transmission , Humans , Molecular Epidemiology , Mutation Rate , Phylogeny , Phylogeography , Sierra Leone/epidemiologyABSTRACT
Human leukocyte antigen (HLA) DNA typing is an essential part to identify a donor who may be a good match for the patients who need haematopoietic stem cells from bone marrow. Thus, fetching quickly high-resolution genotype is very important at present. However, current HLA DNA typing methods especially for HLA-DRB1 generally yielded ambiguous typing results because of high degree of heterozygosity on exome region and primer pairs design limitations, which generally amplified only exon2 of HLA-DRB1 and the position of its primer pairs is on exome region. To solve this problem, we developed a reliable, high-resolution and high-throughput (RHH) sequence based typing approach for HLA-DRB1 through massively parallel paired-end sequencing. Several primer pairs were designed to amplify three exon regions, which are part of exon1, the whole region of exon2 and exon3 of HLA-DRB1, to genotyping for HLA-DRB1 by synthesis. 94 samples were included to analyze and the highly successful genotyping ratio (98.94%) and no ambiguous genotyping result demonstrated the accurate performance of our method for HLA-DRB1 genotyping.
