Measuring paternal discrepancy and its public health consequences

How should we deal with misattributed paternity? A survey of lay public attitudes

Background: Increasing use of genetic technologies in clinical and research settings increases the potential for misattributed paternity to be identified. Yet existing guidance from the President's Commission for the Study of Ethical Problems in Biomedical and Behavioral Research and the Institute of Medicine (among others) offers contradictory advice. Genetic health professionals are thus likely to vary in their practice when misattributed paternity is identified, and empirical investigation into the disclosure of misattributed paternity is scarce. Given the relevance of this ethical dilemma and its significance to users of genetic services, this study aimed to investigate the attitudes of lay people with regard to the disclosure of misattributed paternity. Methods: An online questionnaire was hosted and advertised through Amazon's Mechanical Turk to 200 United States residents aged 18 years or older. Respondents were asked to rate (via a Likert scale) the ethical permissibility of possible actions a clinician may carry out when misattributed paternity is identified. Data analysis consisted of preliminary descriptive analysis, chi-squared analysis, and Wilcoxon signed-rank tests. Results: There was no clear majority support for many of the options surveyed across different contexts, with only six out of ten scenarios displaying some general consensus. Men were more likely to support scenarios where the father is informed of paternity. Importantly, participants' views varied according to whether the desires of the father were previously expressed, suggesting that perceptions of the permissibility of a clinician's action will depend on the interests of all parties affected. Conclusions: This sample of the general public showed attitudes that were, at least to some degree, at variance with some professional guidelines. We give arguments for why at least some of these attitudes might be justified. We argue that case-specific judgments should be made and outline some of the relevant ethical considerations. While general guidelines ought to be considered, context-specific moral judgments cannot be avoided.

Parental Body Mass Index and Behavioral Problems in Their Offspring: A Danish National Birth Cohort Study

Maternal obesity has been associated with increased risk of offspring behavioral problems. We examined whether this association could be explained by familial factors by comparing associations for maternal body mass index (BMI) with associations for paternal BMI. We studied 38,314 children born to mothers enrolled in the Danish National Birth Cohort during 1996-2002. Data on maternal BMI was collected at 15 weeks of gestation, and paternal BMI was assessed when the child was 18 months old. When the child was 7 years old, the Strengths and Difficulties Questionnaire was completed by the parents. We estimated odds ratios for behavioral problems in offspring born to overweight/obese parents, and we found that maternal BMI was associated with offspring behavioral problems. Maternal BMI of 25.0-29.9 was associated with a 33% (odds ratio = 1.33, 95% confidence interval: 1.13, 1.57) higher risk of total difficulties in offspring, and maternal BMI of ≥30.0 was associated with an 83% (odds ratio = 1.83, 95% confidence interval: 1.49, 2.25) higher risk. Paternal obesity was also associated with higher risk of offspring behavioral problems, but stronger associations were observed with maternal prepregnancy obesity. Our results suggest that part of the association between maternal BMI and behavioral problems can be accounted for by genetic and social factors, but environmental risk factors may also contribute to the etiology of behavioral problems.

Nonpaternity and Half-Siblingships as Objective Measures of Extramarital Sex: Mathematical Modeling and Simulations

Background

Understanding the epidemiology of HIV and other sexually transmitted infections (STIs) requires knowledge of sexual behavior, but self-reported behavior has limitations. We explored the reliability and validity of nonpaternity and half-siblings ratios as biomarkers of current and past extramarital sex.

Methods

An individual-based Monte Carlo simulation model was constructed to describe partnering and conception in human populations with a focus on Sub-Saharan Africa (SSA). The model was parameterized with representative biological, behavioral, and demographic data.

Results

Nonpaternity and half-siblings ratios were strongly correlated with extramarital sex, with Pearson correlation coefficients (PCC) of 0.79 (95% CI: 0.71–0.86) and 0.77 (0.68–0.84), respectively. Age-specific nonpaternity ratios correlated with past extramarital sex at time of conception for different scenarios: for example, PCC, after smoothing by moving averages, was 0.75 (0.52–0.89) in a scenario of steadily decreasing nonmarital sex and 0.39 (0.01–0.73) in a scenario of transient drops in nonmarital sex. Simulations assuming self-reported levels of extramarital sex from Kenya yielded nonpaternity levels lower than global nonpaternity data, suggesting sizable underreporting of extramarital sex.

Conclusions

Nonpaternity and half-siblings ratios are useful objective measures of extramarital sex that avoid limitations in self-reported sexual behavior.

Risk of infectious diseases among first-degree relatives of transplant recipients who develop CMV infection: is the infectious phenotype inheritable?

Transplant recipients are at high risk of cytomegalovirus (CMV) infection. Mechanisms explaining the variation in risk of infections are far from fully elucidated. We hypothesised that host genetics explains part of the variation in risk of infection and examined if relatives of recipients with CMV infection have higher rates of severe infections compared to relatives of recipients without this infectious phenotype. In a register-based study, we included first-degree relatives of transplant recipients and examined the risk of hospitalisation due to overall infection or viral infection and risk of death among relatives of recipients who developed CMV infection within the first year of transplantation compared to relatives of recipients without CMV. Analyses were adjusted for sex, age and calendar year. We included 4470 relatives who were followed for 103,786 person-years, median follow-up 24 years [interquartile range (IQR) 12-36]. There were a total of 1360 infection-related hospitalisations in the follow-up period, incidence rate (IR) 13.1/1000 person-years [95% confidence interval (CI), 12.4; 13.8]. 206 relatives were hospitalised with viral infection, IR 1.8/1000 person-years (95% CI, 1.6; 2.0). There was no increased risk of hospitalisation due to infections, IR ratio (IRR) 0.99 (95% CI, 0.88; 1.12), nor specifically viral infections, IRR 0.87 (95% CI, 0.63; 1.19), in relatives of recipients with CMV compared to relatives of recipients without CMV. Also, no difference was seen in analyses stratified by transplant type, family relation and CMV serostatus. The risk of hospitalisation due to infection is not increased among first-degree relatives of transplant recipients with CMV infection compared to relatives of recipients without CMV.

Parental age and childhood cancer risk: A Danish population-based registry study

BACKGROUND

Though the association between parental age at child's birth and the risk of childhood cancer has been previously investigated, the evidence to date is inconclusive and scarce for rarer cancer types.

METHODS

Cancer cases (N=5,856) were selected from all children born from 1968 to 2014 and diagnosed from 1968 to 2015 in Denmark at less than 16 years of age listed in the nationwide Danish Cancer Registry. Cases were individually matched to controls (1:100) on sex and year of birth with a total of 585,594 controls randomly sampled from all live births in Denmark from the Danish Central Population Registry. Parental age at child's birth was extracted from the Central Population Registry. Conditional logistic regression models were used to estimate odds ratios for the association between parental age at child's birth and childhood cancer risk. Parental age was modeled as both categorical (referent group, parents aged 25-29) and continuous per 5-year increase in age.

RESULTS

Offspring of older mothers were at an increased risk of acute lymphoblastic leukemia [OR=1.10, 95% CI: (1.02, 1.19) per 5-year increase in age]. Older maternal age (40+) increased the risk of non-Hodgkin lymphoma [OR=1.96, 95%CI: (1.12, 3.43)]. The risk of Wilms' tumor also appeared elevated with older paternal age [OR=1.11, 95% CI: (0.97, 1.28) per 5-year increment in age].

CONCLUSION

Older parental age was a risk factor for various childhood cancers in Danish children. Further investigation of the biological and social factors that may be contributing to these associations is warranted.

Bioinformatics Approaches for Fetal DNA Fraction Estimation in Noninvasive Prenatal Testing

The discovery of cell-free fetal DNA molecules in plasma of pregnant women has created a paradigm shift in noninvasive prenatal testing (NIPT). Circulating cell-free DNA in maternal plasma has been increasingly recognized as an important proxy to detect fetal abnormalities in a noninvasive manner. A variety of approaches for NIPT using next-generation sequencing have been developed, which have been rapidly transforming clinical practices nowadays. In such approaches, the fetal DNA fraction is a pivotal parameter governing the overall performance and guaranteeing the proper clinical interpretation of testing results. In this review, we describe the current bioinformatics approaches developed for estimating the fetal DNA fraction and discuss their pros and cons.

Maximum number of children per sperm donor based on false paternity rate

PURPOSE

The aim of this study is to estimate the weight of each relevant factor in such unions of inadvertent consanguinity and to determine a "reasonable" limit for the number of children per donor, matching the probability of inadvertent consanguinity arising from the use of sperm donor in assisted reproduction with that of such a union arising from false paternity.

METHODS

In this study, we applied to Spanish data a mathematical model of consanguineous unions, taking into account the following factors: maximum number of live births/donor, fertility rate, average number of births per donor in a pregnancy, donor success rate, matings per phenotype, number of newborns/year, and number of donors needed in the population/year and births by false paternity.

RESULTS

In Spain, the number of inadvertent unions between descendants of the same donor in Spain has been estimated at 0.4/year (one every two and a half years), although this frequency decreases as the reference population increases. On the other hand, the frequency of unions between family members due to false paternity has been estimated at 6.1/year. Thus, only 6% of such unions are due to the use of donor sperm.

CONCLUSION

A total of 25 children per sperm donor are needed to align the probability of inadvertant consanguinity arising from the use of assisted reproduction with that due to false paternity. Therefore, we consider this number to be the maximum "reasonable" number of children born per donor in Spain.

Is there a Role for Genetic Counselors in Prenatal Paternity Testing? - an Assessment Based on Audit of 13 years of Clinical Experience in South Australia

The role of genetic counselors in prenatal paternity testing has not been widely studied in the genetic counseling literature. In South Australia, the genetic counselors of the State's public sector clinical genetics service are the primary contact point for women seeking information and testing, also coordinating the testing process. This has provided the opportunity to review all prenatal paternity testing performed in the State over a 13 year period and to consider the role played by the genetic counselor. We explored the reasons why women requested prenatal paternity testing and whether the genetic counselor was an appropriate health professional to facilitate this testing for women. The study had two parts, an audit of the clinical genetics files of 160 women who requested prenatal paternity testing between March 2001 and March 2014, and qualitative interviews of genetic counselors, clinical geneticists, obstetricians and social workers with involvement in this area. The audit determined that in 69.9 % of cases the long-term partner was the father of the pregnancy, for 23.7 % the short-term or other partner was the father and for 6.4 % the paternity results were not known by the genetic counselor. For 45.5 % of women whose long-term partner was excluded as the father, the women chose to have a termination of pregnancy. The results of the qualitative interviews yielded five major themes: accessibility of testing, role of the genetic counselor, social and relationship issues, decision making in pregnancy and emotional issues. We conclude that the genetic counselor is an appropriate health professional to facilitate prenatal paternity testing. Genetic counselors did not view their role as significantly different from a request for prenatal testing for another indication.

PADRE: Pedigree-Aware Distant-Relationship Estimation

Accurate estimation of shared ancestry is an important component of many genetic studies; current prediction tools accurately estimate pairwise genetic relationships up to the ninth degree. Pedigree-aware distant-relationship estimation (PADRE) combines relationship likelihoods generated by estimation of recent shared ancestry (ERSA) with likelihoods from family networks reconstructed by pedigree reconstruction and identification of a maximum unrelated set (PRIMUS), improving the power to detect distant relationships between pedigrees. Using PADRE, we estimated relationships from simulated pedigrees and three extended pedigrees, correctly predicting 20% more fourth- through ninth-degree simulated relationships than when using ERSA alone. By leveraging pedigree information, PADRE can even identify genealogical relationships between individuals who are genetically unrelated. For example, although 95% of 13(th)-degree relatives are genetically unrelated, in simulations, PADRE correctly predicted 50% of 13(th)-degree relationships to within one degree of relatedness. The improvement in prediction accuracy was consistent between simulated and actual pedigrees. We also applied PADRE to the HapMap3 CEU samples and report new cryptic relationships and validation of previously described relationships between families. PADRE greatly expands the range of relationships that can be estimated by using genetic data in pedigrees.

Familial Aggregation and Heritability of Wuchereria bancrofti Infection

BACKGROUND

The familial recurrence risk of lymphatic filariasis (LF) is unknown. This case study aimed to evaluate the familial susceptibility to infection with Wuchereria bancrofti and to microfilaremia in a village of the Republic of Congo.

METHODS

The heritability and intrafamilial correlation coefficients were assessed for both W. bancrofti infection and microfilaremia by controlling for individual risk factors, environmental influence, and household effects.

RESULTS

Pedigree charts were constructed for 829 individuals, including 143 individuals with a diagnosis of W. bancrofti circulating filarial antigens (CFAs) and 44 who also had microfilariae (MF). There was no intrafamilial correlation regarding CFA levels. However, the presence of MF (ρ = 0.45) and microfilarial density (ρ = 0.44) were significantly correlated among parent-offspring pairs. Heritability estimates for CFA positivity and intensity were 0.23 and 0.18, respectively. Heritability estimates were high for microfilarial positivity (h(2) = 0.74) and microfilarial density traits (h(2) = 0.81).

CONCLUSIONS

Our study suggests that the acquisition of LF is mainly driven by environmental factors and habits and that genetic factors are moderately involved in the regulation of infection. By contrast, genetic factors play a major role in both the presence and intensity of microfilaremia.

FetalQuantSD: accurate quantification of fetal DNA fraction by shallow-depth sequencing of maternal plasma DNA

Noninvasive prenatal testing using massively parallel sequencing of maternal plasma DNA has been rapidly adopted in clinical use worldwide. Fetal DNA fraction in a maternal plasma sample is an important parameter for accurate interpretations of these tests. However, there is a lack of methods involving low-sequencing depth and yet would allow a robust and accurate determination of fetal DNA fraction in maternal plasma for all pregnancies. In this study, we have developed a new method to accurately quantify the fetal DNA fraction by analysing the maternal genotypes and sequencing data of maternal plasma DNA. Fetal DNA fraction was calculated based on the proportion of non-maternal alleles at single-nucleotide polymorphisms where the mother is homozygous. This new approach achieves a median deviation of 0.6% between predicted fetal DNA fraction and the actual fetal DNA fraction using as low as 0.03-fold sequencing coverage of the human genome. We believe that this method will further enhance the clinical interpretations of noninvasive prenatal testing using genome-wide random sequencing.

Birth rates among male cancer survivors and mortality rates among their offspring: a population-based study from Sweden

Background

With improvements in treatment of cancer, more men of fertile age are survivors of cancer. This study evaluates trends in birth rates among male cancer survivors and mortality rates of their offspring.

Methods

From the Swedish Multi-generation Register and Cancer Register, we identified 84,752 men ≤70 years with a history of cancer, for which we calculated relative birth rates as compared to the background population(Standardized Birth Ratios, SBRs). We also identified 126,696 offspring of men who had cancer, and compared their risks of death to the background population(Standardized Mortality Ratio, SMRs). Independent factors associated with reduced birth rates and mortality rates were estimated with Poisson modelling.

Results

Men with a history of cancer were 23 % less likely to father a child compared to the background population(SBR 0.77, 95 % Confidence Interval[CI] 0.75–0.79). Nulliparous men were significantly more likely to father a child after diagnosis (SBR 0.81, 95 % CI 0.79–0.83) compared to parous men (SBR 0.68, 95 % CI 0.66–0.74). Cancer site(prostate), onset of cancer during childhood or adolescence, parity status at diagnosis(parous), current age(>40 years) and a recent diagnosis were significant and independent predictors of a reduced probability of fathering a child after diagnosis.

Of the 126,696 children born to men who have had a diagnosis of cancer, 2604(2.06 %) died during follow up. The overall mortality rate was similar to the background population(SMR of 1.00, 95 %CI 0.96–1.04) and was not affected by the timing of their birth in relation to father’s cancer diagnosis.

Conclusion

Male cancer survivors are less likely to father a child compared to the background population. This is influenced by cancer site, age of onset and parity status at diagnosis. However, their offspring are not at an increased risk of death.

An old problem in a new age: Revisiting the clinical dilemma of misattributed paternity

Clinical genetics has wrestled with the problem of misattributed paternity for decades. While there are no clear directives on policy, surveys suggest that genetics professionals are inclined to avoid disclosure when possible. Changes associated with the increased use of genomic testing will alter the context and may limit the benefits of non-disclosure. Multi-site testing will preclude the uncertainty often associated with single-gene testing. Increased use of genetic testing in clinical and non-clinical settings will create new opportunities for the subsequent unmasking of misattributed relationships, as will the presence of test results in the electronic medical record. Family health history information will become more valuable as it is used more often and to better effect in risk assessment, diagnosis, treatment and reproductive decision-making. These changes associated with genomic testing increase the risks and decrease the benefits associated with the nondisclosure of misattributed paternity. For ethical and practical reasons, genetics professionals, and those who advise them, should consider a greater emphasis on the value of carefully planned disclosure.

WHAT DNA CAN AND CANNOT SAY: PERSPECTIVES OF IMMIGRANT FAMILIES ABOUT THE USE OF GENETIC TESTING IN IMMIGRATION

Genetic technologies are being implemented in areas that extend beyond the field of medicine to address social and legal problems. An emerging example is the implementation of genetic testing in the family petitioning process in immigration policy. This use of genetic testing offers the potential benefits of reducing immigration fraud and making the process more efficient and accessible for immigrants, especially those without documentation. However, little is known about the positive or negative impacts of such testing on immigrant families and their communities. This study collected empirical data through family interviews to understand the experiences and attitudes of individuals who have taken a DNA test to prove a family relationship for immigration purposes. Based on study results, we present a set of recommendations to improve the processes with which DNA testing is applied to immigration cases. We argue that DNA testing might serve as a useful tool for families who lack documentary evidence of a family relationship. However, testing might also reveal sensitive information, such as misattributed parentage, that can damage relationships and cause serious harm to beneficiaries, especially children. Petitioners should be provided with adequate information to form an understanding of the DNA test and its implementation as well as the positive and negative consequences from using it, in order to carefully assess whether DNA testing will help their case. We recommend that additional protections be put in place to safeguard children from the potential impacts of misattributed parentage or disclosure of hidden social adoptions. This research provides empirical evidence to inform policy related to the use of genetic testing in immigration.

Registers of the Swedish total population and their use in medical research

The primary aim of the Swedish national population registration system is to obtain data that (1) reflect the composition, relationship and identities of the Swedish population and (2) can be used as the basis for correct decisions and measures by government and other regulatory authorities. For this purpose, Sweden has established two population registers: (1) The Population Register, maintained by the Swedish National Tax Agency ("Folkbokföringsregistret"); and (2) The Total Population Register (TPR) maintained by the government agency Statistics Sweden ("Registret över totalbefolkningen"). The registers contain data on life events including birth, death, name change, marital status, family relationships and migration within Sweden as well as to and from other countries. Updates are transmitted daily from the Tax Agency to the TPR. In this paper we describe the two population registers and analyse their strengths and weaknesses. Virtually 100 % of births and deaths, 95 % of immigrations and 91 % of emigrations are reported to the Population Registers within 30 days and with a higher proportion over time. The over-coverage of the TPR, which is primarily due to underreported emigration data, has been estimated at up to 0.5 % of the Swedish population. Through the personal identity number, assigned to all residents staying at least 1 year in Sweden, data from the TPR can be used for medical research purposes, including family design studies since each individual can be linked to his or her parents, siblings and offspring. The TPR also allows for identification of general population controls, participants in cohort studies, as well as calculation of follow-up time.

Context and Applications of Targeted Genetic Testing, with Emphasis on Copy Number Variants

There has been a huge acceleration in our technical ability to detect variation in the human genome in recent years, and there has been a corresponding effort in clinical diagnostic laboratories to take advantage of this progress for the benefit of patients. There has, however, not been an equivalent increase in our understanding of human genetics and disease, not for lack of effort but due to the far greater complexity of understanding variation than the difficulties of detecting it. This chapter describes how software tools can be used to target clinical genetic diagnostic testing in order to exploit technical and scientific advances both efficiently and cost-effectively, while maximizing clinical utility.

Social Environments, Genetics, and Black-White Disparities in Infant Mortality

BACKGROUND

Genes and environments often interplay to produce population health. However, in some instances, the scientific literature has favoured one explanation, underplaying the other, even in the absence of rigorous support. We examine parental race disparity on the risk of infant mortality to see if such an analysis might provide clues to understanding the extent to which genes and environment may shape perinatal risks.

METHODS

We assessed parental racial disparities in infant mortality among singletons by analysing the risk of infant mortality among racially consonant vs. dissonant couples over time between 1989-1997 and 1998-2006 in the state of Michigan (n = 1 428 199). We calculated the degree of modification of the relation between maternal race and infant mortality by paternal race dynamically across the two time periods.

RESULTS

Infant mortality among interracial couples decreased with time relative to white-white couples, while infant mortality among black-black couples increased with time after adjusting for socio-economic, demographic, and prenatal care differences. The degree to which paternal black race strengthened the relation between maternal black race and higher infant mortality risk relative to white mothers increased with time throughout our study.

CONCLUSIONS

Evidence from these data suggests that environmental factors likely play the greater role in explaining the parental race disparity and risk of infant mortality.

Estimation of Recent and Ancient Inbreeding in a Small Endogamous Tunisian Community Through Genomic Runs of Homozygosity

Runs of homozygosity (ROHs) are extended genomic regions of homozygous genotypes that record populations' mating patterns in the past. We performed microarray genotyping on 15 individuals from a small isolated Tunisian community. We estimated the individual and population genome-wide level of homozygosity from data on ROH above 0.5 Mb in length. We found a high average number of ROH per individual (48.2). The smallest ROH category (0.5-1.49 Mb) represents 0.93% of the whole genome, while medium-size (1.5-4.99 Mb) and long-size ROH (≥5 Mb) cover 1.18% and 0.95%, respectively. We found that genealogical individual inbreeding coefficients (Fped ) based on three- to four-generation pedigrees are not reliable indicators of the current proportion of genome-wide homozygosity inferred from ROH (FROH ) either for 0.5 or 1.5 Mb ROH length thresholds, while identity-by-descent sharing is a function of shared coancestry. This study emphasizes the effect of reproductive isolation and a prolonged practice of consanguinity that limits the genetic heterogeneity. It also provides evidence of both recent and ancient parental relatedness contribution to the current level of genome-wide homozygosity in the studied population. These findings may be useful for evaluation of long-term effects of inbreeding on human health and for future applications of ROHs in identifying recessive susceptibility genes.

Bioinformatics analysis of circulating cell-free DNA sequencing data

The discovery of cell-free DNA molecules in plasma has opened up numerous opportunities in noninvasive diagnosis. Cell-free DNA molecules have become increasingly recognized as promising biomarkers for detection and management of many diseases. The advent of next generation sequencing has provided unprecedented opportunities to scrutinize the characteristics of cell-free DNA molecules in plasma in a genome-wide fashion and at single-base resolution. Consequently, clinical applications of circulating cell-free DNA analysis have not only revolutionized noninvasive prenatal diagnosis but also facilitated cancer detection and monitoring toward an era of blood-based personalized medicine. With the remarkably increasing throughput and lowering cost of next generation sequencing, bioinformatics analysis becomes increasingly demanding to understand the large amount of data generated by these sequencing platforms. In this Review, we highlight the major bioinformatics algorithms involved in the analysis of cell-free DNA sequencing data. Firstly, we briefly describe the biological properties of these molecules and provide an overview of the general bioinformatics approach for the analysis of cell-free DNA. Then, we discuss the specific upstream bioinformatics considerations concerning the analysis of sequencing data of circulating cell-free DNA, followed by further detailed elaboration on each key clinical situation in noninvasive prenatal diagnosis and cancer management where downstream bioinformatics analysis is heavily involved. We also discuss bioinformatics analysis as well as clinical applications of the newly developed massively parallel bisulfite sequencing of cell-free DNA. Finally, we offer our perspectives on the future development of bioinformatics in noninvasive diagnosis.

Three hundred years of low non-paternity in a human population

When cuckoldry is frequent we can expect fathers to withhold investment in offspring that may not be theirs. Human paternal investment can be substantial and is in line with observations from tens of thousands of conceptions that suggest that cuckoldry is rare in humans. The generality of this claim seems to be in question as the rate of cuckoldry varies across populations and studies have mostly been on Western populations. Two additional factors complicate our conclusions, (1) current estimates of the rate of cuckoldry in humans may not reflect our past behaviour as adultery can be concealed by the use of contraceptives; and (2) it is difficult to obtain samples that are random with respect to their paternity certainty. Studies that combine genealogies with Y-chromosome haplotyping are able to circumvent some of these problems by probing into humans' historical behaviour. Here we use this approach to investigate 1273 conceptions over a period of 330 years in 23 families of the Afrikaner population in South Africa. We use haplotype frequency and diversity and coalescent simulations to show that the male population did not undergo a severe bottleneck and that paternity exclusion rates are high for this population. The rate of cuckoldry in this Western population was 0.9% (95% confidence interval 0.4-1.5%), and we argue that given the current data on historical populations we have to conclude that, at least for Western human populations, cuckoldry rate is probably in the range of 1%.

Parental fat-free mass is related to the fat-free mass of infants and maternal fat mass is related to the fat mass of infant girls

AIM

Existing studies suggest that weight and body composition of parents influence the size and body composition of their offspring, but are often inconclusive and conducted by means of inappropriate body composition methodology. Our aim was to study infant size and body composition variables in relation to body composition variables of their mothers and fathers in a well-nourished population using an accurate methodology.

METHODS

Between 2008 and 2011, we used air displacement plethysmography to measure the body composition of 209 parent-infant units. Parents were measured when women were in gestational week 32. Their healthy, singleton, full-term infants were measured at 1 week.

RESULTS

Infant fat-free mass in grams was positively related (p ≤ 0.007) to the fat-free mass in kilograms of the mothers (15.6 g/kg) and the fathers (9.1 g/kg). Furthermore, the fat mass of the daughters, but not of the sons, was positively related to the fat mass of the mothers (5.8 g/kg, p = 0.007).

CONCLUSION

This study found associations between the fat-free mass of parents and infants and an association between the fat mass of mothers and their infant girls. These findings may help to understand early life factors behind overweight and obesity.

Dynamics of non-cohabiting sex partnering in sub-Saharan Africa: a modelling study with implications for HIV transmission

Objective

To develop an analytical understanding of non-cohabiting sex partnering in sub-Saharan Africa (SSA) using nationally representative sexual behaviour data.

Method

A non-homogenous Poisson stochastic process model was used to describe the dynamics of non-cohabiting sex. The model was applied to 25 countries in SSA and was fitted to Demographic and Health Survey data. The country-specific mean values and variances of the distributions of number of non-cohabiting partners were estimated.

Results

The model yielded overall robust fits to the empirical distributions stratified by marital status and sex. The median across all country-specific mean values was highest for unmarried men at 0.574 non-cohabiting partners over the last 12 months, followed by that of unmarried women at 0.337, married men at 0.192 and married women at 0.038. The median of variances was highest for unmarried men at 0.127, followed by married men at 0.057, unmarried women at 0.003 and married women at 0.000. The largest variability in mean values across countries was for unmarried men (0.103–1.206), and the largest variability in variances was among unmarried women (0.000–1.994).

Conclusions

Non-cohabiting sex appears to be a random ‘opportunistic’ phenomenon linked to situations that may facilitate it. The mean values and variances of number of partners in SSA show wide variation by country, marital status and sex. Unmarried individuals have larger mean values than their married counterparts, and men have larger mean values than women. Unmarried individuals appear to play a disproportionate role in driving heterogeneity in sexual networks and possibly epidemiology of sexually transmitted infections.

Relationships of maternal and paternal anthropometry with neonatal body size, proportions and adiposity in an Australian cohort

The patterns of association between maternal or paternal and neonatal phenotype may offer insight into how neonatal characteristics are shaped by evolutionary processes, such as conflicting parental interests in fetal investment and obstetric constraints. Paternal interests are theoretically served by maximizing fetal growth, and maternal interests by managing investment in current and future offspring, but whether paternal and maternal influences act on different components of overall size is unknown. We tested whether parents' prepregnancy height and body mass index (BMI) were related to neonatal anthropometry (birthweight, head circumference, absolute and proportional limb segment and trunk lengths, subcutaneous fat) among 1,041 Australian neonates using stepwise linear regression. Maternal and paternal height and maternal BMI were associated with birthweight. Paternal height related to offspring forearm and lower leg lengths, maternal height and BMI to neonatal head circumference, and maternal BMI to offspring adiposity. Principal components analysis identified three components of variability reflecting neonatal “head and trunk skeletal size,” “adiposity,” and “limb lengths.” Regression analyses of the component scores supported the associations of head and trunk size or adiposity with maternal anthropometry, and limb lengths with paternal anthropometry. Our results suggest that while neonatal fatness reflects environmental conditions (maternal physiology), head circumference and limb and trunk lengths show differing associations with parental anthropometry. These patterns may reflect genetics, parental imprinting and environmental influences in a manner consistent with parental conflicts of interest. Paternal height may relate to neonatal limb length as a means of increasing fetal growth without exacerbating the risk of obstetric complications. Am J Phys Anthropol 156:625–636, 2015.

PRIMUS: rapid reconstruction of pedigrees from genome-wide estimates of identity by descent

Understanding and correctly utilizing relatedness among samples is essential for genetic analysis; however, managing sample records and pedigrees can often be error prone and incomplete. Data sets ascertained by random sampling often harbor cryptic relatedness that can be leveraged in genetic analyses for maximizing power. We have developed a method that uses genome-wide estimates of pairwise identity by descent to identify families and quickly reconstruct and score all possible pedigrees that fit the genetic data by using up to third-degree relatives, and we have included it in the software package PRIMUS (Pedigree Reconstruction and Identification of the Maximally Unrelated Set). Here, we validate its performance on simulated, clinical, and HapMap pedigrees. Among these samples, we demonstrate that PRIMUS can verify reported pedigree structures and identify cryptic relationships. Finally, we show that PRIMUS reconstructed pedigrees, all of which were previously unknown, for 203 families from a cohort collected in Starr County, TX (1,890 samples).

Incidental findings of nonparentage: a case for universal nondisclosure

We advocate for the incorporation of a new clause into the consent forms for pediatric genetic testing that clearly states that any incidental information about parentage will not be revealed, regardless of the result. Using a case of misattributed maternity, we examine both the pro- and antidisclosure arguments. In the absence of arguments that clearly demonstrate irrevocable harm from nondisclosure and against a backdrop of arguments that compellingly highlight the potential for serious harms from disclosing incidental findings of nonparentage, we advocate for a universal, institution-wide policy of nondisclosure. Our proposed policy of universal nondisclosure not only provides a viable solution to the disclosure dilemma but also empowers patients to know what testing is available to them and to seek it out on their own terms, fully informed. With an easily implemented consent change, clinics can take a clear and firm stance in the disclosure debate. As a result, patients will be protected, policy will be widely understood, and cases will be resolved consistently and clearly.

Low historical rates of cuckoldry in a Western European human population traced by Y-chromosome and genealogical data

Recent evidence suggests that seeking out extra-pair paternity (EPP) can be a viable alternative reproductive strategy for both males and females in many pair-bonded species, including humans. Accurate data on EPP rates in humans, however, are scant and mostly restricted to extant populations. Here, we provide the first large-scale, unbiased genetic study of historical EPP rates in a Western European human population based on combining Y-chromosomal data to infer genetic patrilineages with genealogical and surname data, which reflect known historical presumed paternity. Using two independent methods, we estimate that over the last few centuries, EPP rates in Flanders (Belgium) were only around 1–2% per generation. This figure is substantially lower than the 8–30% per generation reported in some behavioural studies on historical EPP rates, but comparable with the rates reported by other genetic studies of contemporary Western European populations. These results suggest that human EPP rates have not changed substantially during the last 400 years in Flanders and imply that legal genealogies rarely differ from the biological ones. This result has significant implications for a diverse set of fields, including human population genetics, historical demography, forensic science and human sociobiology.

Birth of children with severe β-thalassemia at a tertiary obstetric hospital: what are the reasons behind it?

OBJECTIVE

To find reasons for the births of severe β-thalassemia at a tertiary obstetric hospital in mainland China.

METHODS

All cases with confirmed diagnosis of β-thalassemia major were included from 1 January 2007 to 31 December 2011. The main clinical characteristics of the affected pregnancies were reviewed, including maternal reproductive history, prenatal care in the current pregnancy, the gestation of pregnancy at the time of booking, and availability of husbands for a screen test.

RESULTS

A total of nine cases of β-thalassemia major were identified at birth during the study period. The reasons for no prenatal diagnosis included unavailability of the father for a test in four cases, unacceptability of the invasive procedure in two cases, absence of prenatal care in two cases, and nonpaternity in one case.

CONCLUSION

The effectiveness in control of the disease is not only associated with the model itself but also the factors playing against the model. The identification of the main reasons for the birth of severe thalassemia might help to find room for improvement in clinical practice.

[Continuous medical evaluation of the prevention of fetomaternal rhesus-D allo-immunization]

OBJECTIVES

To evaluate the prevention of fetomaternal rhesus-D allo-immunization between 2008 and 2010. This evaluation was a part of the continuous medical evaluation (CME) that is compulsory in French hospitals. It was carried out using the tools recommended by the Haute Autorité de santé. We followed the national guidelines for the prevention of fetomaternal rhesus-D allo-immunization as outlined in 2005 by the national French college of Obstetrics and Gynecology.

MATERIALS AND METHODS

We audited 3926 consultations in the first four months of 2008. Based on the results of the audit, actions were implemented to improve care. In 2009, we audited 4021 consultations to look for improvement, and another 3932 consultations in 2010.

RESULTS

In 2008, 14% of the patients had an overall optimal prevention. After actions were taken, 44% of patients in 2009 and 58% of patients in 2010 demonstrated optimal prevention (P<0,05). Especially, the prevention of fetomaternal allo-immunization has been explained for 43% of the patients in 2008 and to 90% of them in 2010. And immunoprophylaxia has been prescribed to 70% of the patients in 2008 and to 93% of them in 2010.

CONCLUSION

This CME has resulted in a statistically significant improvement of the prevention of allo-immunization.

Pedigree and genotyping quality analyses of over 10,000 DNA samples from the Generation Scotland: Scottish Family Health Study

Background

Generation Scotland: Scottish Family Health Study (GS:SFHS) is a family-based biobank of 24,000 participants with rich phenotype and DNA available for genetic research. This paper describes the laboratory results from genotyping 32 single nucleotide polymorphisms (SNPs) on DNA from over 10,000 participants who attended GS:SFHS research clinics. The analysis described here was undertaken to test the quality of genetic information available to researchers. The success rate of each marker genotyped (call rate), minor allele frequency and adherence to Mendelian inheritance are presented. The few deviations in marker transmission in the 925 parent-child trios analysed were assessed as to whether they were likely to be miscalled genotypes, data or sample handling errors, or pedigree inaccuracies including non-paternity.

Methods

The first 10,450 GS:SFHS clinic participants who had spirometry and smoking data available and DNA extracted were selected. 32 SNPs were assayed, chosen as part of a replication experiment from a Genome-Wide Association Study meta-analysis of lung function.

Results

In total 325,336 genotypes were returned. The overall project pass rate (32 SNPs on 10,450 samples) was 97.29%. A total of 925 parent-child trios were assessed for transmission of the SNP markers, with 16 trios indicating evidence of inconsistency in the recorded pedigrees.

Conclusions

The Generation Scotland: Scottish Family Health Study used well-validated study methods and can produce good quality genetic data, with a low error rate. The GS:SFHS DNA samples are of high quality and the family groups were recorded and processed with accuracy during collection of the cohort.

Genetics specialists' perspectives on disclosure of genomic incidental findings in the clinical setting

OBJECTIVE

Evidence documenting management of incidental findings (IFs) from clinical genomic testing is limited. The aim of this study was to examine genetics specialists' perspectives regarding current and preferred disclosure of clinical genomic IFs.

METHODS

50 genetics specialists, including medical geneticists, laboratory professionals, genetic counselors, and nurses participated in structured telephone interviews. Data were analyzed using qualitative content analysis and descriptive statistics.

RESULTS

Most specialists had encountered IFs, but definitions of IFs varied. They discussed challenges with informing patients about the prospect of IFs and disclosing IFs to patients. Causing psychological harm to patients was a concern. Participants were divided on whether IFs needed to be clinically significant and/or actionable in order to be disclosed to patients. Creating formal disclosure guidelines was considered useful, but only if they were flexible. Additional counseling, more interdisciplinary communication, maintaining contact with patients, and a centralized database to interpret IFs were also proposed.

CONCLUSION

Genetics specialists offer insights into the challenges of defining IFs, knowing when and how to disclose them, and the potential need for flexible disclosure guidelines.

PRACTICE IMPLICATIONS

Further discussion between practicing genetics specialists is needed to develop consensus on the development of best-practice guidelines for IF management.

Improving the rigor of mutation reports: biologic parentage and de novo mutations

The accurate determination and dissemination of the causality or pathogenicity of human DNA sequence variants is a crucial function of genetics journals. Published reports of pathogenic mutations are a common source of information for mutation databases, which are in turn used to make recommendations to patients. One of the strongest pieces of evidence in support of causality or pathogenicity for mutation reports is the occurrence of a de novo mutation. Yet, many publications describing such changes do not demonstrate that the mutation is truly de novo, by performing biologic parentage testing. I argue here that all mutation reports that describe such mutations should include biologic parentage testing, or in the absence of such testing, the mutation should be described as "apparently de novo." This proposed standard should improve the transparency of the evidence that underlies our literature, and ultimately improve the databases of mutations in human disease.

A de novo germline MLH1 mutation in a Lynch syndrome patient with discordant immunohistochemical and molecular biology test results

We describe a patient with a Homo sapiens mutL homolog 1 (MLH1)-associated Lynch syndrome with previous diagnoses of two distinct primary cancers: a sigmoid colon cancer at the age of 39 years, and a right colon cancer at the age of 50 years. The mutation identified in his blood and buccal cells, c.1771delG, p.Asp591Ilefs*25, appears to be a de novo event, as it was not transmitted by either of his parents. This type of de novo event is rare in MLH1 as only three cases have been reported in the literature so far. Furthermore, the discordant results observed between replication error phenotyping and immunohistochemistry highlight the importance of the systematic use of both pre-screening tests in the molecular diagnosis of Lynch syndrome.

Non-invasive prenatal measurement of the fetal genome

The vast majority of prenatal genetic testing requires invasive sampling. Since this poses a risk to the fetus, one must make a decision that weighs the desire for genetic information against the risk of an adverse outcome due to hazards of the testing process. These issues are not required to be coupled, and it would be desirable to discover genetic information about the fetus without incurring a health risk. Here we demonstrate that it is possible to noninvasively sequence the entire prenatal genome. Our results show that molecular counting of parental haplotypes in maternal plasma by shotgun sequencing of maternal plasma DNA allows the inherited fetal genome to be deciphered noninvasively. We also applied the counting principle directly to each allele in the fetal exome by performing exome capture on maternal plasma DNA prior to shotgun sequencing. This approach enables noninvasive exome screening of clinically relevant and deleterious alleles that were paternally inherited or had arisen as de novo germline mutations, and complements the haplotype counting approach to provide a comprehensive view of the fetal genome. Noninvasive determination of the fetal genome may ultimately facilitate the diagnosis of all inherited and de novo genetic disease.

Adolescent grandchildren's perceptions of grandparents' involvement in UK: an interpretation from life course and evolutionary theory perspective

In this article, we study grandparental involvement from the viewpoint of evolutionary theory and sociological life course perception. We have used 'the Involved Grandparenting and Child Well-Being 2007' survey, which is the first nationally representative sample of British and Welsh adolescents aged 11-16 (n = 1,488). First, we explore with the descriptive statistics the amount of grandparental involvement reported by adolescents. The result follows the predicted pattern: maternal grandparent is reported to involve in a grandchild's life the most, second maternal grandfather, third paternal grandmother and the last paternal grandfather. Second, we focus more closely on separate grandparents and show with four linear regression models which factors are connected to each grandparent's involvement. Grandchild's age, grandparent's health, grandparent's labour force participation and distance between a grandparent and a grandchild were factors that have similar effects in relation to all grandparents. Marital status mattered only for grandfathers, whereas family structure of a grandchild has opposite effects in relation to maternal and paternal grandparents. Grandchild's sex, grandparent's age, the number of grandchildren and the number of living grandparents all mattered, but only with respect to some grandparents. The study shows that it is advantageous to merge sociological and evolutionary viewpoints when studying a grandparental involvement in a modern society.

Intellectual disability and other neuropsychiatric outcomes in high-risk children of mothers with schizophrenia, bipolar disorder and unipolar major depression

BACKGROUND

Recent evidence points to partially shared genetics of neuropsychiatric disorders.

AIMS

We examined risk of intellectual disability and other neuropsychiatric outcomes in 3174 children of mothers with schizophrenia, bipolar disorder or unipolar major depression compared with 3129 children of unaffected mothers.

METHOD

We used record linkage across Western Australian population-based registers. The contribution of obstetric factors to risk of intellectual disability was assessed.

RESULTS

Children were at significantly increased risk of intellectual disability with odds ratios (ORs) of 3.2 (95% CI 1.8-5.7), 3.1 (95% CI 1.9-4.9) and 2.9 (95% CI 1.8-4.7) in the maternal schizophrenia, bipolar disorder and unipolar depression groups respectively. Multivariate analysis suggests familial and obstetric factors may contribute independently to the risk. Although summated labour/delivery complications (OR = 1.4, 95% CI 1.0-2.0) just failed to reach significance, neonatal encephalopathy (OR = 7.7, 95% CI 3.0-20.2) and fetal distress (OR = 1.8, 95% CI 1.1-2.7) were independent significant predictors. Rates of rare syndromes in children of mothers with mental disorder were well above population rates. Risk of pervasive developmental disorders, including autism, was significantly elevated for children of mothers with bipolar disorder. Risk of epilepsy was doubled for children of mothers with unipolar depression.

CONCLUSIONS

Our findings provide epidemiological support for clustering of neuropsychiatric disorders. Further larger epidemiological studies are warranted.

Screening for sickle cell and thalassaemia in primary care: a cost-effectiveness study

BACKGROUND

Haemoglobinopathies, including sickle cell disease and thalassaemia (SCT), are inherited disorders of haemoglobin. Antenatal screening for SCT rarely occurs before 10 weeks of pregnancy.

AIM

To explore the cost-effectiveness of offering SCT screening in a primary care setting, during the pregnancy confirmation visit.

DESIGN AND SETTING

A model-based cost-effectiveness analysis of inner-city areas with a high proportion of residents from ethnic minority groups.

METHOD

Comparison was made of three SCT screening approaches: 'primary care parallel' (primary care screening with test offered to mother and father together); 'primary care sequential (primary care screening with test offered to the mother and then the father only if the mother is a carrier); and 'midwife care' (sequential screening at the first midwife consultation). The model was populated with data from the SHIFT (Screening for Haemoglobinopathies In First Trimester) trial and other sources.

RESULTS

Compared to midwife care, primary care sequential had a higher NHS cost of £34,000 per 10,000 pregnancies (95% confidence interval [CI] = £15,000 to £51,000) and an increase of 2623 women screened (95% CI: 1359 to 4495), giving a cost per additional woman screened by 10 weeks of £13. Primary care parallel was dominated by primary care sequential, with both higher costs and fewer women screened.

CONCLUSION

The policy judgement is whether an earlier opportunity for informed reproductive choice has a value of at least £13. Further work is required to understand the value attached to earlier informed reproductive choices.