State-wide utilization and performance of traditional and cell-free DNA-based prenatal testing pathways: the Victorian Perinatal Record Linkage (PeRL) study

OBJECTIVES

To perform individual record linkage of women undergoing screening with cell-free DNA (cfDNA), combined first-trimester screening (CFTS), second-trimester serum screening (STSS), and/or prenatal and postnatal cytogenetic testing with the aim to (1) obtain population-based estimates of utilization of prenatal screening and invasive diagnosis, (2) analyze the performance of different prenatal screening strategies, and (3) report the residual risk of any major chromosomal abnormality following a low-risk aneuploidy screening result.

METHODS

This was a retrospective study of women residing in the state of Victoria, Australia, who underwent prenatal screening or invasive prenatal diagnosis in 2015. Patient-funded cfDNA referrals from multiple providers were merged with state-wide results for government-subsidized CFTS, STSS and invasive diagnostic procedures. Postnatal cytogenetic results from products of conception and infants up to 12 months of age were obtained to ascertain cases of false-negative screening results and atypical chromosomal abnormalities. Individual record linkage was performed using LinkageWiz^TM .

RESULTS

During the study period, there were 79 140 births and 66 166 (83.6%) women underwent at least one form of aneuploidy screening. Linkage data were complete for 93.5% (n = 61 877) of women who underwent screening, and of these, 73.2% (n = 45 275) had CFTS alone, 20.2% (n = 12 486) had cfDNA alone; 5.3% (n = 3268) had STSS alone, 1.3% (n = 813) had both CFTS and cfDNA, and < 0.1% (n = 35) had both STSS and cfDNA. CFTS had a combined sensitivity for trisomies 21 (T21), 18 (T18) and 13 (T13) of 89.57% (95% CI, 82.64-93.93%) for a screen-positive rate (SPR) of 2.94%. There were 12 false-negative results in the CFTS pathway, comprising 10 cases of T21, one of T18 and one of T13. cfDNA had a combined sensitivity for T21, T18 and T13 of 100% (95% CI, 95.00-100%) for a SPR of 1.21%. When high-risk cfDNA results for any chromosome (including the sex chromosomes) and failed cfDNA tests were treated as screen positives, the SPR for cfDNA increased to 2.42%. The risk of any major chromosomal abnormality (including atypical abnormalities) detected on prenatal or postnatal diagnostic testing after a low-risk screening result was 1 in 1188 for CFTS (n = 37) and 1 in 762 for cfDNA (n = 16) (P = 0.13). The range of chromosomal abnormalities detected after a low-risk cfDNA result included pathogenic copy-number variants (n = 6), triploidy (n = 3), rare autosomal trisomies (n = 3) and monosomy X (n = 2).

CONCLUSIONS

Our state-wide record-linkage analysis delineated the utilization and clinical performance of the multitude of prenatal screening pathways available to pregnant women. The sensitivity of cfDNA for T21, T18 and T13 was clearly superior to that of CFTS. While there was no statistically significant difference in the residual risk of any major chromosomal abnormality after a low-risk CFTS or cfDNA result, there were fewer live infants diagnosed with a major chromosomal abnormality in the cfDNA cohort. These data provide valuable population-based evidence to inform practice recommendations and health policies. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Population-based trends in invasive prenatal diagnosis for ultrasound-based indications: two decades of change from 1994 to 2016

OBJECTIVE

To assess trends in ultrasound-indicated prenatal diagnostic testing performed over the past two decades in the Australian state of Victoria, in the context of rapidly changing practices in aneuploidy screening and chromosome analysis.

METHODS

This was a retrospective analysis of all ultrasound-indicated prenatal diagnostic testing (amniocentesis and chorionic villus sampling) performed in the state of Victoria between 1994 and 2016. Ultrasound indications for testing included: fetal structural abnormality, fetal death, fetal growth restriction, abnormal amniotic fluid volume, genetic 'soft marker' and unspecified ultrasound abnormality. Maternal age, indication for testing, type of diagnostic procedure, gestational age, type of chromosome analysis (G-banded karyotyping or chromosomal microarray (CMA)) and test results were obtained. Diagnostic yield (i.e. percentage of tests yielding a major abnormality) was analyzed by year, maternal age and gestational age. Statistical analysis was performed using the χ² tests for trend or difference in proportions, as appropriate.

RESULTS

During the 23-year study period, 1 533 317 births were recorded and 16 152 diagnostic procedures were performed for the primary indication of ultrasound abnormality. In recent years, ultrasound abnormality became the most common indication for prenatal invasive testing (29.4% of diagnostic tests between 2013 and 2016) due to a steep decline in testing for other indications such as positive result on combined first-trimester screening or advanced maternal age alone. In 2016, over 95% of ultrasound-indicated procedures were performed with CMA; among these, pathogenic copy number variant (CNV) was the most common (3.5%) abnormality detected, followed by trisomy 21 (2.8%). The diagnostic yield of ultrasound-indicated tests performed < 16 weeks was significantly higher than that of tests performed after 20 weeks (31.5% vs 9.0%).

CONCLUSIONS

Ultrasound-indicated invasive testing is contributing to prenatal diagnosis in new ways in the genomic era. A pathogenic CNV is now the most likely diagnosis after ultrasound-indicated testing, rather than trisomy 21 or other whole-chromosome aneuploidy. Despite steady improvements in first-trimester screening for aneuploidy, the diagnostic yield of ultrasound-indicated tests > 20 weeks has remained stable due to increased utilization of CMA. Procedures performed for structural abnormalities < 16 weeks continue to have the highest diagnostic yield, supporting the benefits of early fetal structural assessment at 11-13 weeks. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal diagnostic testing and atypical chromosome abnormalities following combined first-trimester screening: implications for contingent models of non-invasive prenatal testing

OBJECTIVES

To investigate by means of a population-based analysis of a cohort of women who underwent combined first-trimester screening (CFTS), changes in uptake of invasive prenatal diagnosis according to risk of trisomy 21 (T21) on CFTS, and prevalence and methods for ascertainment of atypical chromosome abnormalities.

METHODS

This was a retrospective cohort study using state-wide prenatal datasets from Victoria, Australia. A three-step approach was taken to analyze the data: (1) linkage of records between serum screening and diagnostic results; (2) comparison of rates of diagnostic testing according to CFTS T21 risk result category in a 2014-2015 cohort with those of a historical 2002-2004 cohort; (3) detailed analysis of atypical abnormalities in the 2014-2015 group according to CFTS T21 risk result, individual serum analyte level and other indications for invasive diagnostic testing.

RESULTS

In 2014-2015, there were 100 418 CFTS results issued for 146 776 births (68.4%). The overall prevalence of atypical chromosome abnormalities in the entire CFTS cohort was 0.10% and was highest in those with CFTS T21 risk > 1 in 10 (4.6%), or serum analyte levels < 0.2 multiples of the median (MoM) (6.9% for pregnancy-associated plasma protein-A (PAPP-A) and 5.2% for beta-human chorionic gonadotropin (β-hCG)). Almost half (49.2%) of women with PAPP-A < 0.2 MoM had a risk for T21 on CFTS of less than 1 in 100. The majority (55%) of atypical abnormalities occurred in women with CFTS T21 risk below 1 in 300, and were most commonly detected on ultrasound examination (47.1%).

CONCLUSION

Concerns regarding missed diagnoses of atypical chromosome abnormalities when non-invasive prenatal testing is offered after a result of high risk on CFTS can be mitigated if invasive diagnostic testing is offered to those women with CFTS T21 risk of > 1 in 100, serum PAPP-A or β-hCG < 0.2 MoM, or ultrasound-detected abnormality. This has implications for contingent models of screening. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Growth on stimulant medication; clarifying the confusion: a review

AIMS

To get an overview of the studies of growth in height in children with attention deficit hyperactivity disorder (ADHD) treated with stimulant medication, to establish the consistencies and to try to resolve the discrepancies.

METHODS

Twenty nine studies were reviewed following a Medline search: 22 related to children, six to late adolescents or adults, and one to children and adults.

RESULTS

Children: Eleven studies gave results consistent with height attenuation on stimulant medication: eight were longitudinal, one was cross-sectional, and two showed growth rebound on ceasing medication. Studies with negative findings were inadequately powered (n = 3), lacked controls or statistical analysis (n = 3), measured height velocity without reference to treatment duration (n = 2), or used inappropriate growth parameters (n = 1), controls (n = 1), or normative data (n = 1). Late adolescents/adults treated with stimulant medication in childhood: Two studies associated childhood gastrointestinal side effects with attenuated late adolescent or adult height; all six cross-sectional studies had negative findings. The methodologies varied widely but there was some consistency in the degree of attenuation shown in studies with positive findings. The most sensitive methods analysed the changes in z-scores (standard deviation scores) or calculated the height deficits from paired measurements taken before and after an initial period of treatment with stimulant medication. The height deficit amounted to approximately 1 cm/year during the first 1-3 years of treatment.

CONCLUSIONS

Further research is needed into the causal mechanisms, the rate of physical maturation, and the long term implications for final stature.

Slowing of growth in height and weight on stimulants: a characteristic pattern

OBJECTIVE

The aims of the present study were to describe the growth pattern of children starting stimulant medication and to analyse the changes over time in height, weight and height velocity in a cohort of treated patients.

METHODS

Retrospective review of growth data from files of all newly treated patients with attention-deficit/hyperactivity disorder in one paediatric practice. Forty-four boys and seven girls were treated for 6-42 months with either dexam-phetamine (n = 32) or methylphenidate (n = 19).

RESULTS

During the first 6 months on stimulant medication 44 children (86%) had a height velocity below the age-corrected mean and there was weight loss in 39 (76%). The height and weight standard deviation score (SDS) showed a progressive decline that was statistically significant after 6 and 18 months (P < 0.001, paired t-test). The height velocity was significantly attenuated for the first 30 months (P < 0.01), being lowest during the first 6 months. The mean height deficit during the first 2 years was approximately 1 cm/year. The change in weight SDS was 2.4 times the change in height SDS after 30 months on treatment with a significant correlation (Pearson's correlation coefficient r = 0.88, P < 0.001).

CONCLUSIONS

Stimulant medication is associated with a decrease in height and weight SDS during the first 6-30 months with a characteristic pattern on the growth chart.

A wireless telemetry system for training users of upper limb prostheses

Telemetry from prosthetic systems is useful in aiding the users and clinical team in setting up and training and monitoring in the use of a prosthesis. The different forms are discussed and a new radio frequency based telemetry system is described. This system uses a computer to display the data and a video mixer to place the information on the same screen as the image of the user so that their actions and control signals can be simultaneously recorded for later study.

Open spina bifida: a complete cohort reviewed 25 years after closure

This study summarises the long-term results of non-selective treatment of open spina bifida. Every member of a consecutive series of 117 cases was ascertained 22 to 28 years after closure of the back. 56 of the cohort had died. The condition of the 61 survivors ranged from normal to severe disability. Only 33 of the survivors were capable of living independently, 11 required supervision and some help, and 17 needed daily care which was generally provided by the parents. The two main determinants of disability and dependency were the extent of the neurological deficit and IQ. Improvements in the management of patients with open spina bifida have greatly reduced mortality, but they are less likely to influence long-term disability since that is dependent on the severity of the neurological deficit.

Retrospective study of children with renal scarring associated with reflux and urinary infection

OBJECTIVE

To review the histories of children with bilateral renal scarring and severe vesicoureteric reflux to determine whether an improvement in early management might reduce the risk of scarring.

DESIGN

Retrospective study of medical records and discussion with parents.

SETTING

Outpatient departments of two teaching hospitals.

PATIENTS

52 children aged 1-12 years participating in a randomised comparison of medical and surgical management. All had a history of symptomatic urinary tract infection. Two thirds presented with fever and two with hypertension or renal failure. In only one out of 32 children examined by antenatal ultrasonography was an abnormality suspected.

RESULTS

There was delay in diagnosis or appropriate imaging or effective treatment of urinary infection in 50 of the 52 children. In 41 there was delay in diagnosis; there was delay in treating a confirmed infection in 45; no antibacterial prophylaxis was prescribed before imaging in 28; and investigation of the urinary tract was delayed in 33. The severity of scarring was significantly related to delay in diagnosis (chi 2 for trend 7.43, P = 0.01). Four children of mothers known to have reflux nephropathy were not investigated until they developed urinary tract infection.

CONCLUSIONS

Efforts to reduce the incidence and severity of renal scarring should be directed towards rapid diagnosis and effective early management of urinary tract infection in infancy and childhood. Siblings and offspring of known patients with severe reflux nephropathy should be investigated for reflux.

Oral mannitol in control of fluid balance

Oral mannitol 40 g/m2 was given as 5.5% and 20% solutions to six dialysed children. Both solutions caused diarrhoea. Body weight showed no significant change after the 5.5% solution, which may be used as 'free drink', but fell by 19.8 g/g mannitol after the 20% solution.

Short-term variations of circulating melatonin in the ewe

Melatonin levels have been studied in venous blood sampled at different frequencies (0.5-, 2-, and 60-min intervals) form intact ewes. All samples were taken during the dark phase of either natural or artificial photoperiods. In one experiment samples were taken simultaneously from both jugular veins to investigate the possible effects of "streaming" on the levels measured. Plasma cortisol was measured to ascertain whether or not the frequent removal of blood activated the ACTH stress axis. Plasma melatonin levels showed considerable variation with peaks of up to 365 pg/ml on a baseline of between 30 and 60 pg/ml. There was consistent evidence of intermittent peaks, the frequency of which increased with an increase in sampling frequency. Plasma cortisol showed no correlation with either the frequency or the amplitude of the melatonin peaks. When plasma samples were taken from both jugular veins a similar melatonin pattern was seen in the samples from both sides, but samples taken from the left jugular vein invariably showed higher levels than those taken from the right vein. This may be due to differential vascular drainage of the pineal to the two sides.