Maternal cell-free DNA–based screening for fetal microdeletion and the importance of careful diagnostic follow-up

BackgroundNoninvasive prenatal screening (NIPS) by next-generation sequencing of cell-free DNA (cfDNA) in maternal plasma is used to screen for common aneuploidies such as trisomy 21 in high risk pregnancies. NIPS can identify fetal genomic microdeletions; however, sensitivity and specificity have not been systematically evaluated. Commercial companies have begun to offer expanded panels including screening for common microdeletion syndromes such as 22q11.2 deletion (DiGeorge syndrome) without reporting the genomic coordinates or whether the deletion is maternal or fetal. Here we describe a phenotypically normal mother and fetus who tested positive for atypical 22q deletion via maternal plasma cfDNA testing.MethodsWe performed cfDNA sequencing on saved maternal plasma obtained at 11 weeks of gestation from a phenotypically normal woman with a singleton pregnancy whose earlier screening at a commercial laboratory was reported to be positive for a 22q11.2 microdeletion. Fluorescence in situ hybridization and chromosomal microarray diagnostic genetic tests were done postnatally.ConclusionNIPS detected a 22q microdeletion that, upon diagnostic workup, did not include the DiGeorge critical region. Diagnostic prenatal or postnatal testing with chromosomal microarray and appropriate parental studies to determine precise genomic coordinates and inheritance should follow a positive microdeletion NIPS result.     

Teenage pregnancy and congenital anomalies: which system is vulnerable?

BACKGROUND: Teenage pregnancy may be associated with some forms of congenital anomalies. The objective of this study was to identify the types of congenital anomalies associated with teenage pregnancy. METHODS: We carried out a retrospective cohort study of 5 542 861 nulliparous pregnant women younger than 35 years of age with a live singleton birth between 1995 and 2000 in the USA. RESULTS: Compared with adult pregnancy (20-34 years old), and after adjustment for confounding variables, teenage pregnancy (13-19 years old) was associated with increased risk of central nervous system anomalies [odds ratio (OR) 1.08; 95% confidence interval (CI): 1.01, 1.16], gastrointestinal anomalies (OR: 1.39; 95% CI: 1.31, 1.49) and musculoskeletal/integumental anomalies (OR: 1.06; 95% CI: 1.03, 1.10). The teenage pregnancy associated increase in risk for central nervous system anomalies was mainly attributable to anomalies other than anencephalus, spina bifida/meningocele and hydrocephalus and microcephalus; for gastrointestinal anomalies the risk was mainly attributable to omphalocele/gastroschisis; and for musculoskeletal/integumental anomalies the risk was mainly attributable to cleft lip/palate and polydactyly/syndactyly/adactyly. No increased risk was found for circulatory/respiratory anomalies, urogenital anomalies, or Down's syndrome. CONCLUSIONS: Teenage pregnancy increases the risks of congenital anomalies in central nervous, gastrointestinal and musculoskeletal/integumental systems.     

Carrier screening panels for Ashkenazi Jews: is more better?

PURPOSE: To describe the characteristics of Ashkenazi Jewish carrier testing panels offered by US Laboratories, including what diseases are included, the labels used to describe the panels, and the prices of individual tests compared to the prices of panels for each laboratory. METHODS: GeneTests (http://www.genetests.org) was searched for laboratories that offered Tay-Sachs disease testing. Information was obtained from laboratory web sites, printed brochures, and telephone calls about tests/panels. RESULTS: Twenty-seven laboratories offered up to 10 tests. The tests included two diseases associated with death in childhood (Niemann-Pick type A and Tay-Sachs disease), five with moderate disability and a variably shortened life span (Bloom syndrome, Canavan disease, cystic fibrosis, familial dysautonomia, Fanconi anemia, and mucolipidosis type IV), and two diseases that are not necessarily disabling or routinely shorten the lifespan (Gaucher disease type I and DFNB1 sensorineural hearing loss). Twenty laboratories offered a total of 27 panels of tests for three to nine diseases, ranging in price from $200 to $2082. Of these, 15 panels cost less than tests ordered individually. The panels were described by 24 different labels; eight included the phrase Ashkenazi Jewish Disease or disorder and six included the phrase Ashkenazi Jewish Carrier. CONCLUSION: There is considerable variability in the diseases, prices, and labels of panels. Policy guidance for establishing appropriate criteria for inclusion in panels may be useful to the Ashkenazi Jewish community, clinicians, and payers. Pricing strategies that offer financial incentives for the use of "more tests" should be reexamined.     

Screening for fetal and neonatal alloimmune thrombocytopenia: is it possible and what are the potential outcomes?

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare but potentially very serious bleeding condition affecting the fetus/newborn. The vast majority (>80%) of FNAIT cases among Caucasians, and the most serious one, are caused by maternal antibodies to the human platelet antigen 1a (HPA‐1a). The clinical consequences of FNAIT span a continuum from no symptoms to intracranial haemorrhage (ICH) and intrauterine death. The incidence of FNAIT‐associated ICH has been estimated to be around 1 in 10 000 newborns. For many reasons, FNAIT has not been considered for prophylactic efforts similar to those that have been used for the prevention of HDFN, caused by antibodies against RhD: first, HPA‐1a typing kits are not well suited to the workflow in immunohaematology laboratories; secondly, the costs associated with HPA‐1a typing of all pregnant women have been a hindrance; thirdly, there is no international consensus regarding the optimal antenatal management of HPA‐1a‐immunized women identified in a screening programme; fourthly, it has generally been believed that immunization against HPA‐1a mostly takes place during the first incompatible pregnancy, and finally, there is yet no medicinal product available that can prevent HPA‐1a‐immunization in the same way as anti‐D can prevent RhD immunization. Implementation of HPA‐1a typing of all pregnant women has been discussed by the health authorities in several European countries. The abovementioned five hindrances for FNAIT screening and the Wilson and Jungner criteria for screening programmes will be discussed in the light of recent advances within FNAIT research.     

Is cervical swab an efficient method for developing a new noninvasive prenatal diagnostic test for numerical and structural chromosome anomalies?

Background/aim Prenatal diagnosis is vital to obtain healthy generation for risky pregnancies. There have been several approaches, some of which are routinely applied in clinics to evaluate the possible prenatal deficiencies and/or diseases. In the present study, we aimed to isolate the fetal cells from endocervical samples and try to identify possible anomalies which were proved by Amniocentesis (AS) and chorionic villus sampling (CVS) methods.Materials and methodsEndoservical specimens were collected from 100 pregnant women. Cells were separated in parallel by fluorescence-activated cell sorting (FACS) and magnetic-activated cell sorting (MACS) using human leukocyte antigen (HLA) G233 and placental alkaline phosphatase (PLAP) antibodies. CMA (comprehensive meta-analysis) were carried out and male fetuses were confirmed with Sex determining region Y (SRY) amplification.Results The percent of HLA G233 and placental and placental alkaline phosphatase (PLAP) positive cells were 4.55% and 84.59%, respectively. The percent of cells positive for both markers was 14.75%. CMA analyses were not informative. (SRY) was amplified in 67% of the samples.Conclusion However, the success rate of the both cell sorting and scanning of DNA anomalies by aCGH and/or RT-PCR was limited, preventing the applicability of this proposal in the clinics. Still, the success of the proposed method depends on the development of the novel fetal cell-specific antibodies and the improvements in the sorting systems.     

Paternal age and birth defects: how strong is the association?

BACKGROUND: Although the association between maternal age and the risks of birth defects has been well studied, the evidence from population data linking paternal age with birth defects was limited and inconsistent. METHODS: We conducted a population-based retrospective cohort study of 5,213,248 subjects from the 1999-2000 birth registration data of the USA. Multiple logistic regressions were used to estimate the independent effect of paternal age on all birth defects and 21 specific defects groups after adjusting for potential confounding of maternal age, race, education, marital status, parity, prenatal care initiation, maternal smoking and alcohol drinking during pregnancy. RESULTS: A total of 77,514 (1.5%) birth defects were recorded in the study cohort. The adjusted odds ratios were 1.04 (1.01, 1.06), 1.08 (1.04, 1.12), 1.08 (1.02, 1.14) and 1.15 (1.06, 1.24), respectively, for infants born to fathers 30-35, 40-44, 45-49 and over 50 years (test for trend, P = 0.0155), when compared with those infants born to fathers aged 25-29 for any birth defect. Advanced paternal age was associated with increased risks of heart defects, tracheo-oesophageal fistulaoesophageal atresia, other musculoskeletal/integumental anomalies, Down's syndrome and other chromosomal anomalies. Fathers under 25 years of age were also at increased risks of spina bifida/meningocele, microcephalus, omphalocele/gastroschisis and other musculoskeletal/integumental anomalies. CONCLUSIONS: Infants born to older fathers have a slightly increased risk of birth defects. Young paternal age is also associated with slightly increased risk of several selected birth defects in their offspring. However, given the weak association, paternal age appears to play a small role in the aetiology of birth defects.     

Hepatitis C: is there a case for universal screening in pregnancy?

Hepatitis C (HCV) is not routinely screened for antenatally in all maternity hospitals. Most hospitals adopt a policy of targeted screening. The policy in the Coombe Women and Infants University Hospital in Dublin changed from targeted screening in 2006 to universal screening in 2007. We audited the two consecutive years. The prevalence of HCV in our antenatal population was 1.4% for 2006 (67/4666) when targeted screening applied and in 2007--0.71% (66/9222) when universal screening came into affect. One woman in 2007 would not have been detected by targeted screening--1.49% (1/67). Fifty five percent (37/67) of women were HCV-RNA positive in 2006 and 57.5% (38/66) were positive in 2007. We conclude that there were similar detection rates for HCV in 2006 and 2007 and that universal screening is not required if inclusive criteria for selective screening are employed but is of use in research context.     

The effects of advanced maternal age on T-cell subsets at the maternal–fetal interface prior to term labor and in the offspring: a mouse study

Women who conceive at 35 years of age or older, commonly known as advanced maternal age, have a higher risk of facing parturition complications and their children have an increased risk of developing diseases later in life. However, the immunological mechanisms underlying these pathological processes have yet to be established. To fill this gap in knowledge, using a murine model and immunophenotyping, we determined the effect of advanced maternal age on the main cellular branch of adaptive immunity, T cells, at the maternal–fetal interface and in the offspring. We report that advanced maternal age impaired the process of labor at term, inducing dystocia and delaying the timing of delivery. Advanced maternal age diminished the number of specific proinflammatory T-cell subsets [T helper type 1 (Th1): CD4⁺IFN-γ⁺, CD8⁺IFN-γ⁺ and Th9: CD4⁺IL-9⁺], as well as CD4⁺ regulatory T cells (CD4⁺CD25⁺FoxP3⁺ T cells), at the maternal–fetal interface prior to term labor. Advanced maternal age also altered fetal growth and survival of the offspring in early life. In addition, infants born to advanced-age mothers had alterations in the T-cell repertoire but not in CD71⁺ erythroid cells (CD3⁻CD71⁺TER119⁺ cells). This study provides insight into the immune alterations observed at the maternal–fetal interface of advanced-age mothers and their offspring.     

Informed consent documents for BRCA1 and BRCA2 screening: how large is the readability gap?

The decision to undergo testing for the BRCA1 and BRCA2 mutations, which are associated with an increased risk of breast and ovarian cancer, can have long-term consequences on women's lives. Women who decide to undergo such testing are required to sign informed consent documents, which indicate that they understand the test and its risks and benefits. These documents are generally written for advanced-level readers. However, the reading abilities of many women are substantially lower than the level of the consent forms, resulting in a 'readability gap'. This disparity suggests that women may not fully understand the documents they are asked to sign. The 'readability gap' poses the serious issues about informed consent, raising questions about institutional review boards and the effectiveness of the documents that are currently in use.     

The Othmer and DeSouza test for screening of somatisation disorder: is it useful in general practice?

BACKGROUND: Somatisation disorder is an underdiagnosed and difficult problem for family physicians. Early diagnosis of somatisers is a very important factor in improving health outcomes. AIM: To assess the validity of the Othmer and DeSouza test (a seven-item questionnaire) used by general practitioners as a screening instrument for the diagnosis of somatisation disorder in primary care. DESIGN OF STUDY: A cross-sectional study of patients presenting with unexplained multiple chronic physical symptoms. SETTING: A total of 149 patients were selected for the study by 29 family physicians in the primary health care centres of the Basque Health Service in the metropolitan area of Bilbao, Bizkaia, Spain. METHODS: Participating patients completed the Othmer and DeSouza test, carried out by family physicians. Their answers were compared with the results of the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). This psychiatric interview was administered blind to 144 patients by trained psychiatrists. RESULTS: A total of 19% of patients were diagnosed as having somatisation disorder by the SCAN psychiatric interview. The discriminating capacity of the Othmer and DeSouza test for all possible screening thresholds (> or = 1, > or = 2, ... > or = 6 symptoms) was very low and positive predictive values ranged between 19% and 33%. With respect to negative predictive values, even in the absence of affirmative responses to all seven questions, the pretest probability of being a non-somatiser case remained unchanged. CONCLUSION: Our data indicate that the Othmer and DeSouza test does not present clinically useful predictive values in primary care patients with suggestive symptoms of somatisation disorder.     

Genetic screening for reproductive purposes at school: is it a good strategy?

Thalassemia and Tay-Sachs disease were the first diseases in which the criteria for heterozygote genetic screening were met and successful programs for reproductive purposes were initiated in populations at risk. However, many of the couples first discover the possibility of genetic screening during pregnancy and efforts are made to bring couples to consider screening tests before the first pregnancy. In this context, high school offers a convenient setting and several pilot programs have been very successful. All evaluations of these programs found that education plays a critical role in allowing informed decisions and minimizing the possible harms. While it has been suggested that high school may be the best setting for reproductive screening programs, guidelines of several societies of human genetics recommend the use of carrier screening only in individuals older than 18 years. There are several other problems related to genetic screening programs at school and some are discussed in the review. Our opinion is that school should be a place to provide the tools for decisions by education only; while the option to have the genetic tests later in life or in another setting should be offered to the students as part of the education session. This may allow the students to decide when and where to have a genetic test.     

Informed decision-making in prenatal screening for Down's syndrome: What knowledge is relevant?

Objective

To determine the content of decision-relevant knowledge needed for informed decision-making about (non-) participation in prenatal screening for Down's syndrome (DS), in order to develop a knowledge questionnaire for routine application in large-scale programme evaluations.

Methods

A generic list of content domains for knowledge about screening was extracted from the literature. Items reflecting specific knowledge domains were constructed. An expert group of professionals and pregnant women expressed whether domains and items represented decision-relevant information.

Results

All presented domains were scored as (very) important. Options when receiving an ‘increased probability for DS’ test result, the meaning of this result, the aim of the screening, and voluntary nature of the test were scored as most important. The condition being screened for, prevalence, and the screening procedure were scored as relatively less important, with a high amount of expert consensus.

Conclusion

A knowledge measure for prenatal screening for DS was developed, based on domains and items acquired by expert consensus.

Practice implications

This measure of decision-relevant knowledge can be used in routine, large-scale evaluations of the procedure for offering information about prenatal screening for DS.     

Histopathological screening for prostate carcinoma: is a benign biopsy a negative biopsy?

In case of clinical suspicion of a prostate malignancy, a prostate biopsy is the most widely used approach to confirm prostate cancer. Unfortunately, exclusion of prostate cancer is not feasible by means of biopsy and also the negative rate remains consistently high. Here, we review the information the surgical pathologist can still gain from a prostate biopsy in absence of overt carcinoma.     

Maternal nutrition: how is Eastern and Southern Africa faring and what needs to be done?

Background

The progress in key maternal health indicators in the Eastern and Southern Africa Region (ESAR) over the past two decades has been slow.

Objective

This paper analyzed available information on nutrition programs and nutrition-specific interventions targeting maternal nutrition in the ESAR and proposes steps to improve maternal nutrition in this region.

Methods

Search was conducted in relevant databases. Meta-analysis was done where there was sufficient data, while data from the nutrition programs was abstracted for objectives, settings, beneficiaries, stakeholders, impact of interventions and barriers encountered during implementation.

Results

Findings from our review suggest that multiple nutrition programs are in place in the ESAR; including programs that directly address nutrition indicators and those that integrate corresponding sectors like agriculture, health, education, and water and sanitation. However, their scale and depth differ considerably. These programs have been implemented by a diverse range of players including respective government ministries, international agencies, non government organisations and the private sector in the region. Most of these programs are clustered in a few countries like Kenya, Uganda and Ethiopia while others e.g. Comoros, Somalia and Swaziland have only had a limited number of initiatives.

Conclusion

These programs have been associated with some improvements in overall maternal health and nutritional indicators; however these are insufficient to significantly contribute to the progress in the region. Efforts should be prioritized in countries with the greatest burden of maternal undernutrition and associated risk factors with a focus on existing promising interventions to improve maternal nutrition.     

On the use of the outcome variable “small for gestational age” when gestational age is a potential mediator: a maternal asthma perspective

Background

The variable “small for gestational age,” frequently defined as birth weight below the 10th percentile in a gestational age and sex-normalized population, is nowadays generally perceived as a more adequate measure than birth weight or low birth weight (birth weight?<?2500 g) to capture fetal growth. However, the use of small for gestational age rather than birth weight or low birth weight as an outcome (dependent) variable may have important impacts on the interpretation of analyses aimed at estimating the causal effect of an exposure of interest on infants. We hypothesized potential differences in both types of effects estimated (direct or total) and in ability to control for confounding bias.

Methods

We first examined the use of outcome variables birth weight and small for gestational age to get insights on modeling practices within the field of maternal asthma. Using directed acyclic graph simulations where gestational age was a potential mediator, we then compared estimated exposure effects in regression models for birth weight, low birth weight, and small for gestational age. Graphs with and without confounding were considered.

Results

Our simulations showed that the variable small for gestational age captures the direct effect of exposure on birth weight, but not the indirect effect of exposure on birth weight through gestational age. Interestingly, exposure effect estimates from small for gestational age models were found unbiased whenever exposure effect estimates from birth weight models were affected by collider bias due to conditioning on gestational age in the models.

Conclusions

The sole consideration of the outcome small for gestational age in a study may lead to suboptimal understanding and quantification of the underlying effect of an exposure on birth weight-related measures. Instead, our results suggest that both outcome variables (low) birth weight and small for gestational age should minimally be considered in studies investigating perinatal outcomes.

     

Ageing and Parkinson's disease: Why is advancing age the biggest risk factor?

As the second most common age related neurodegenerative disease after Alzheimer's disease, the health, social and economic impact resulting from Parkinson's disease will continue to increase alongside the longevity of the population. Ageing remains the biggest risk factor for developing idiopathic Parkinson's disease. Although research into the mechanisms leading to cell death in Parkinson's disease has shed light on many aspects of the pathogenesis of this disorder, we still cannot answer the fundamental question, what specific age related factors predispose some individuals to develop this common neurodegenerative disease. In this review we focus specifically on the neuronal population associated with the motor symptoms of Parkinson's disease, the dopaminergic neurons of the substantia nigra, and try to understand how ageing puts these neurons at risk to the extent that a slight change in protein metabolism or mitochondrial function can push the cells over the edge leading to catastrophic cell death and many of the symptoms seen in Parkinson's disease. We review the evidence that ageing is important for the development of Parkinson's disease and how age related decline leads to the loss of neurons within this disease, before describing exactly how advancing age may lead to substantia nigra neuronal loss and Parkinson's disease in some individuals.