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Objective: Cell-free DNA (cfDNA) screening assesses both maternal and placental cfDNA. Fibroids are common and release cfDNA into maternal serum. Genetic abnormality is seen in 50% of fibroids. We aimed to assess the impact of fibroids on the accuracy of genome-wide cfDNA screening.Methods: This was a prospective cohort study of singleton pregnancies examined at one of two centers in Melbourne and Sydney, Australia, between 1 November 2019 and 31 December 2020. All cases underwent pretest ultrasound examination to confirm an ongoing pregnancy of at least 10 weeks' gestation, and, at this stage, the number and volume of any uterine fibroid were documented. Genome-wide cfDNA screening was performed to detect all copy-number variants (CNV) > 7 megabases. The incidence of a false-positive result was compared between cases with and those without fibroids.Results: Over the 14-month study period, 13 184 patients underwent cfDNA screening, of whom 1017 (7.7%) had fibroids. Fibroids were not identified in any of the 17 participants who had a false-positive result for chromosomes 13, 18, 21, X or Y. Ninety-five (0.7%) cases were screen-positive for subchromosomal aberration (SA), rare autosomal trisomy (RAT) or multiple abnormalities (MA), with 10 of these cases having a fetal genetic abnormality. The incidence of a false-positive RAT, MA or SA result was significantly higher in participants with fibroids (20/1017 (2.0%)) than in those without fibroids (64/12 167 (0.5%)). Women with fibroids were approximately six times as likely to have a false-positive result for SA, and this was associated positively with both fibroid number and volume.Conclusions: Most women with fibroids do not have an abnormal result on genome-wide cfDNA screening. However, CNVs due to fibroids are associated with false-positive SA findings, although fibroids do not appear to influence cfDNA screening accuracy for the common autosomal trisomies or sex-chromosomal abnormalities. © 2021 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Despite the prevalence of sclerophyllous vegetation in Australia, there are few phylogeographic studies with continent-wide sampling addressing questions about the expansion of this vegetation post-aridification, and what physical barriers are associated with breaks in distribution or patterns of genetic structure. We used amplicon sequencing of plastid and nuclear DNA to investigate phylogeography of Xanthorrhoea. Despite extremely low genetic variation and widespread sharing of identical DNA sequence among multiple species and across significant geographic distance, haplotype analyses showed phylogeographic structure. Network analysis of six plastid loci and 137 samples identified 54 haplotypes (two common, 35 unique to single samples) in three geographic groups, south west and central Australia, northern–eastern Australia, and southern–eastern Australia, indicating restricted gene flow among regions. A nrDNA haplotype network of 152 samples showed less variation, with one haplotype being widespread, found in all three plastid geographic groups and 70% of species. nrDNA indicated four groups in a pattern, suggestive of at least two east–west divergences. A geographic area of a high haplotype diversity and divergence was identified in southern New South Wales, near the Southern Transition Zone. Our results showed the value of targeted amplicon sequencing and using multiple samples per species to identify both broad-scale and fine-scale biogeographic patterns. Amplicon sequencing of plastid and nuclear DNA showed phylogeographic structure in Xanthorrhoea , despite extremely low genetic variation and widespread sharing of identical DNA sequence among multiple species (sometimes across significant geographic distance). Plastid loci identified three geographic groups, South West + Central Australia, North East Australia, and South East Australia, indicating restricted gene flow among regions. nrDNA sequence showed less variation, with one haplotype being widespread, found in all three plastid geographic groups and 70% of species, and a pattern suggesting at least two east–west divergences. [ABSTRACT FROM AUTHOR]

Invasive sambar deer (Rusa unicolor) are having significant detrimental impacts on natural environments in south-eastern Australia. Little, however, is known about their ecology, limiting evidence-based management strategies directed at reducing deer impacts. Genetic data, generated from DNA isolated from deer scats, can be used to fill ecological knowledge gaps. This study outlines a non-invasive genetic sampling strategy by which good-quality DNA from a single deer scat can be used to determine (1) species of origin, (2) sex and (3) a unique DNA profile. DNA from deer tissue and sambar deer scat samples were used to develop and optimise molecular methods to collect reliable genetic information. A DNA toolbox is presented that describes how to find, collect and store scat samples, isolate DNA and use molecular markers to generate informative genetic data. Generating genetic data using this approach will support studies aimed at acquiring ecological knowledge about sambar deer. Such knowledge will be critical for developing evidence-based recommendations to improve on-ground management decisions for sambar deer. [ABSTRACT FROM AUTHOR]

Cell‐free DNA screening has quickly become established in Australia as an accurate – albeit costly – prenatal screening test for trisomy 21, 18 and 13. It is also commonly used for the detection of sex chromosome abnormalities. The increasing number of prenatal screening pathways available to women has increased the complexity of pretest counselling. Concurrent advances in diagnostic testing with the widespread use of chromosomal microarrays create further challenges for the continuing education of clinicians and health consumers. This article aims to answer common clinical questions in this rapidly evolving field and complements the recently updated Royal Australian and New Zealand College of Obstetricians and Gynaecologists Statement on Prenatal Screening for Fetal Chromosome and Genetic Conditions. [ABSTRACT FROM AUTHOR]

Background There are limited data regarding noninvasive prenatal testing ( NIPT) in low-risk populations, and the ideal aneuploidy screening model for a pregnant population has yet to be established. Aims To assess the implementation of NIPT into clinical practice utilising both first- and second-line screening models. Materials and Methods Three private practices specialising in obstetric ultrasound and prenatal diagnosis in Australia offered NIPT as a first-line test, ideally followed by combined first-trimester screening ( cFTS), or as a second-line test following cFTS, particularly in those with a calculated risk between 1:50 and 1:1000. Results NIPT screening was performed in 5267 women and as a first-line screening method in 3359 (63.8%). Trisomies 21 and 13 detection was 100% and 88% for trisomy 18. Of cases with known karyotypes, the positive predictive value ( PPV) of the test was highest for trisomy 21 (97.7%) and lowest for monosomy X (25%). Ultrasound detection of fetal structural abnormality resulted in the detection of five additional chromosome abnormalities, two of which had high-risk cFTS results. For all chromosomal abnormalities, NIPT alone detected 93.4%, a contingent model detected 81.8% ( P = 0.097), and cFTS alone detected 65.9% ( P < 0.005). Conclusions NIPT achieved 100% T21 detection and had a higher DR of all aneuploidy when used as a first-line test. Given the false-positive rate for all aneuploidies, NIPT is an advanced screening test, rather than a diagnostic test. The benefit of additional cFTS was the detection of fetal structural abnormalities and some unusual chromosomal abnormalities. [ABSTRACT FROM AUTHOR]

In late 2012, a new screening test for fetal aneuploidy based on circulating cell-free DNA (cfDNA) became available to Australian women. The introduction of this technology in the United States has led to a reduction in invasive diagnostic procedures. Analysis of the number of amniocentesis and chorionic villus sampling (CVS) procedures performed in Australia from 1994 to 2014 shows that the introduction of cfDNA testing has been associated with the most rapid decline in invasive procedures in the last 20 years. This change has important implications for training in, and maintenance of, the procedural skills of amniocentesis and CVS., (© 2015 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)