Measuring paternal discrepancy and its public health consequences

py_ped_sim: a flexible forward pedigree and genetic simulator for complex family pedigree analysis

BACKGROUND

Large-scale family pedigrees are commonly used across medical, evolutionary, and forensic genetics. These pedigrees are tools for identifying genetic disorders, tracking evolutionary patterns, and establishing familial relationships via forensic genetic identification. However, there is a lack of software to accurately simulate different pedigree structures along with genomes corresponding to those individuals in a family pedigree. This limits simulation-based evaluations of methods that use pedigrees.

RESULTS

We have developed a python command-line-based tool called py_ped_sim that facilitates the simulation of pedigree structures and the genomes of individuals in a pedigree. py_ped_sim represents pedigrees as directed acyclic graphs, enabling conversion between standard pedigree formats and integration with the forward population genetic simulator, SLiM. Notably, py_ped_sim allows the simulation of varying numbers of offspring for a set of parents, with the capacity to shift the distribution of sibship sizes over generations. We additionally add simulations for events of misattributed paternity, which offers a way to simulate half-sibling relationships, and simulations to extend the breadth of a family pedigree. We validated the accuracy of both our genome simulator and pedigree simulator. We show that we can simulate genomes onto family pedigrees with levels of expected kinship.

CONCLUSIONS

py_ped_sim is a user-friendly and open-source solution for simulating pedigree structures and conducting pedigree genome simulations. It empowers medical, forensic, and evolutionary genetics researchers to gain deeper insights into the dynamics of genetic inheritance and relatedness within families.

Associations between past infectious mononucleosis diagnosis and 47 inflammatory and vascular stress biomarkers

Infectious mononucleosis (IM), predominantly caused by primary Epstein-Barr virus (EBV) infection, is a common disease in adolescents and young adults. EBV infection is nearly ubiquitous globally. Although primary EBV infection is asymptomatic in most individuals, IM manifests in a subset infected during adolescence or young adulthood. IM occurrence is linked to sibship structure, and is associated with increased risk of multiple sclerosis, other autoimmune diseases, and cancer later in life. We analyzed 47 biomarkers in 5,526 Danish individuals aged 18-60 years, of whom 604 had a history of IM, examining their associations with IM history up to 48 years after IM diagnosis. No significant long-term associations were observed after adjusting for multiple comparisons. When restricting the analysis to individuals measured within 10 years post-IM diagnosis, a statistically significant increase in CRP levels was observed in females. This association was not driven by oral contraceptive use. No significant associations between sibship structure and biomarker levels were detected. In conclusion, our study shows that while IM may lead to a transient increase in CRP levels in females, it does not result in long-term alterations in plasma biomarkers related to immune function, suggesting other mechanisms may be responsible for the long-term health impacts associated with IM.

A polygenic score for height identifies an unmeasured genetic predisposition among pediatric patients with idiopathic short stature

BACKGROUND

A subset of children with short stature do not have an identified clinical explanation after extensive diagnostic evaluation. We hypothesized that a polygenic score for height (PGSheight) could identify children with non-familial idiopathic short stature (ISS-NF) who carry a polygenic predisposition to shorter height that is not accounted for by existing measures.

METHODS

We studied 534 pediatric participants in an electronic health record (EHR)-linked DNA biobank (BioVU) who had been evaluated for short stature by an endocrinologist. Participants were classified as having one of five short stature subtypes: primary growth disorders, secondary growth disorders, idiopathic short stature (ISS), which was sub-classified into familial (ISS-F) and non-familial (ISS-NF), and constitutional delay of puberty (ISS-DP). Differences in polygenic predisposition between subtypes were analyzed using a validated PGSheight which was standardized to a standard deviation score (SDS). Adult height predictions were generated using the PGSheight and mid-parental height (MPH). Within-child differences in height predictions were compared across subtypes. Logistic regression models and AUC analyses were used to test the ability of the PGSheight to differentiate ISS-NF from growth disorders. The incremental improvement (ΔAUC) of adding the PGSheight to prediction models with MPH was also estimated.

RESULTS

Among the 534 participants, 29.0% had secondary growth disorders, 24.9% had ISS-F, 20.2% had ISS-NF, 17.2% had ISS-DP, and 8.6% had primary growth disorders. Participants with ISS-NF had similar PGSheight values to those with ISS-F (difference [Δ] in PGSheight SDS [95% CI] = 0.19 [- 0.31 to 0.70], p = 0.75). Predicted heights generated by the PGSheight were lower than the MPH estimate for children with ISS-NF (Δ[PGSheight - MPH] =  - 0.37 SDS; p = 3.2 × 10-9) but not for children with ISS-F (Δ =  - 0.07; p = 0.56). Children with ISS-NF also had lower PGSheight than children with primary growth disorders (ΔPGSheight =  - 0.53 [- 1.03 to - 0.04], p = 0.03) and secondary growth disorders (Δ =  - 0.45 [- 0.80 to - 0.10], p = 0.005). The PGSheight improved model discrimination between ISS-NF and children with primary (ΔAUC, + 0.07 [95% CI, 0.02 to 0.17]) and secondary growth disorders (ΔAUC, + 0.03 [95% CI, 0.01 to 0.10]).

CONCLUSIONS

Some children with ISS-NF have an unrecognized polygenic predisposition to shorter height, similar to children with ISS-F and greater than those with growth disorders. A PGSheight could aid clinicians in identifying children with a benign, polygenic predisposition to shorter height.

Misattributed paternity discovery: A critique of medical organizations' recommendations

The five authors recently discovered their misattributed paternity (MP), two ascertaining that, decades ago, their pediatricians abetted the paternity deception. From their unique perspective, the authors critique medical organizations' current MP discovery guidance, identifying shortcomings, contradictions, and clinical and legal hazards. They also discuss opportunities to improve MP discovery management.

Impact of prenatal and postnatal maternal IBD status on offspring's risk of IBD: a population-based cohort study

OBJECTIVE

In utero exposure to maternal inflammation may impact immune system development and subsequent risk of disease. We investigated whether a maternal diagnosis of IBD before childbirth is linked to a higher risk of IBD in offspring compared with a diagnosis after childbirth. Further, we analysed paternal IBD status for comparison.

DESIGN

Using Danish health registers, we identified all individuals born in Denmark between 1997 and 2022 and their legal parents, as well as their IBD status. Cox proportional hazards regression analyses adjusted for calendar period and mode of delivery were used to estimate offspring IBD risk by maternal and paternal IBD status before and after childbirth.

RESULTS

Of 1 290 358 children, 10 041 (0.8%) had mothers with IBD diagnosis before childbirth and 9985 (0.8%) had mothers with IBD diagnosis after childbirth. Over 18 370 420 person-years, 3537 individuals were diagnosed with IBD. Offspring of mothers with IBD before childbirth had an adjusted HR of IBD of 6.27 (95% CI 5.21, 7.54) compared with those without maternal IBD, while offspring of mothers with IBD after childbirth had an adjusted HR of 3.88 (95% CI 3.27, 4.60). Corresponding adjusted HRs were 5.26 (95% CI 4.22, 6.56) among offspring with paternal IBD before childbirth and 3.73 (95% CI 3.10, 4.50) for paternal IBD after childbirth.

CONCLUSION

Offspring had a greater risk of IBD when either parent was diagnosed before childbirth rather than later, emphasising genetic predisposition and environmental risk factors rather than maternal inflammation in utero as risk factors for IBD.

Universal screening for familial hypercholesterolaemia: how can we maximise benefits and minimise potential harm for children and their families?

PURPOSE OF REVIEW

Universal Screening programmes to identify subjects with familial hypercholesterolaemia (FH) have been the subject of much recent interest. However, any screening programme can cause harm as well as having potential benefits. Here we review recent papers using different ages and strategies to identify subjects with FH, and examine to what extent the publications provide quantitative or qualitative evidence of benefit or harm to children and adults.

RECENT FINDINGS

Three studies have been published over the last 2 years where Universal Screening for FH has been carried out in infancy, at the time of routine vaccinations, or at preschool age. Next-generation sequencing of all known FH-causing genes has been used to determine the proportion of screened individuals, who have total or low-density lipoprotein cholesterol (LDL-C) concentrations above a predetermined threshold (such as >95th percentile), with genetically confirmed FH.

SUMMARY

While we fully support the concept of Universal Screening for FH, which appears feasible and of potential clinical utility at all of the different ages examined, there is little data to document potential benefit or how to mitigate potential harms. Future study protocols should include collection of such data to strengthen the case of roll out of Universal Screening programmes.

A polygenic score for height identifies an unmeasured genetic predisposition among pediatric patients with idiopathic short stature

Background

A subset of children with short stature do not have an identified clinical explanation and are assigned a diagnosis of idiopathic short stature (ISS). We hypothesized that a polygenic score for height (PGSheight) could identify children with ISS who have an unrecognized heritable predisposition to shorter height.

Methods

We examined 534 pediatric participants in an EHR-linked DNA biobank (BioVU) who had undergone an evaluation for short stature by an endocrinologist. We used a previously validated PGSheight and standardized it to a standard deviation (SDS) of 1. PGSheight differences between short stature subtypes was estimated using Tukey's HSD. The PGSheight and mid-parental height (MPH) were then used to predict adult heights for each participant and these predictions were compared using Cohen's d stratifying by short stature subtype. The ability of the PGSheight to discriminate between ISS and short stature due to underlying disease was evaluated using logistic regression models with area under the ROC curve (AUC) analyses and testing the incremental benefit (ΔAUC) of adding the PGSheight to prediction models.

Results

Among the 534 participants, 22.1% had ISS (median [IQR] PGSheight SDS = -1.31 [-2.15 to -0.47]), 6.6% had familial (genetic) short stature (FSS) (-1.62 [-2.13 to -0.54]), and 45.1% had short stature due to underlying pathology (-0.74 [-1.23 to -0.19]). Children with ISS had similar PGSheight values as those with FSS (ΔPGSheight [95% CI] = 0.19 [-0.31 to 0.70], p = 0.75), but predicted heights generated by the PGSheight were lower than the MPH estimate for children with ISS (d = -0.64; p = 4.0×10-18) but not FSS (d = 0.05; p = 0.46), suggesting that MPH underestimates height in the ISS group. Children with ISS had lower PGSheight values than children with pathology (ΔPGSheight = -0.60 SDS [-0.89 to -0.31], p < 0.001), suggesting children with ISS have a larger predisposition to shorter height. In addition, the PGSheight improved model discrimination between ISS and pathologic short stature (ΔAUC, + 0.07 [95% CI, 0.01 to 0.11]).

Conclusions

Some children with ISS have a clinically unrecognized polygenic predisposition to shorter height that is comparable to children with FSS and larger than those with underlying pathology. A PGSheight could help clinicians identify children who have a benign predisposition to shorter height.

Consanguinité et son impact sur la santé et la dynamique du génome : Un exemple de la Tunisie

The genetic disease spectrum in Tunisia arises from the founder effect, genetic drift, selection, and consanguinity. The latter represents a deviation from panmixia, characterized by a non-random matrimonial choice that may be subject to several rules, such as socio-cultural, economic, or other factors. This shifts the genetic structure away from the Hardy-Weinberg equilibrium, increasing homozygous genotypes and decreasing heterozygotes, thus raising the frequency of autosomal recessive diseases. Similar to other Arab populations, Tunisia displays high consanguinity rates that vary geographically. Approximately 60% of reported diseases in Tunisia are autosomal recessive, with consanguinity possibly occurring in 80% of families for a specific disease. In inbred populations, consanguinity amplifies autosomal recessive disease risk, yet it does not influence autosomal dominant disease likelihood but rather impacts its phenotype. Consanguinity is also suggested to be a major factor in the homozygosity of deleterious variants leading to comorbid expression. At the genome level, inbred individuals inherit homozygous mutations and adjacent genomic regions known as runs of homozygosity (ROHs). Short ROHs indicate distant inbreeding, while long ROHs refer to recent inbreeding. ROHs are distributed rather irregularly across the genome, with certain short regions featuring an excess of ROH, known as ROH islands. In this review, we discuss consanguinity's impact on population health and genome dynamics, using Tunisia as a model.

Assessing Recommendations for Determining Fetal Risk in Alloimmunized Pregnancies in the United States: Is It Time to Update a Decades-Old Practice?

The current recommended testing algorithm for assessing the alloimmunized pregnancy utilized by many obstetricians in the United States (US) fails to consider the most recent evidence, placing fetuses, and mothers at unnecessary risk of poor outcome or death. This narrative review of the current landscape of fetal red blood cell (RBC) antigen testing evaluates the history of hemolytic disease of the fetus and newborn (HDFN) and how its discovery has continued to influence practices in the US today. We compare current US-based HDFN practice guidelines with those in Europe. We also provide transfusion medicine and hematology perspectives and recommendations addressing the limitations of US practice, particularly regarding paternal RBC antigen testing, and discuss the most valuable alternatives based on decades of data and evidence-based recommendations from Europe.

Guideline No. 448: Prevention of Rh D Alloimmunization

OBJECTIVE

This guideline provides recommendations for the prevention of Rh D alloimmunization (isoimmunization) in pregnancy, including parental testing, routine postpartum and antepartum prophylaxis, and other clinical indications for prophylaxis. Prevention of red cell alloimmunization in pregnancy with atypical antigens (other than the D antigen), for which immunoprophylaxis is not currently available, is not addressed in this guideline.

TARGET POPULATION

All Rh D-negative pregnant individuals at risk for Rh D alloimmunization due to potential exposure to a paternally derived fetal Rh D antigen.

OUTCOMES

Routine postpartum and antepartum Rh D immunoprophylaxis reduces the risk of Rh D alloimmunization at 6 months postpartum and in a subsequent pregnancy.

BENEFITS, HARMS, AND COSTS

This guideline details the population of pregnant individuals who may benefit from Rho(D) immune globulin (RhIG) immunoprophylaxis. Thus, those for whom the intervention is not required may avoid adverse effects, while those who are at risk of alloimmunization may mitigate this risk for themselves and/or their fetus.

EVIDENCE

For recommendations regarding use of RhIG, Medline and Medline in Process via Ovid and Embase Classic + Embase via Ovid were searched using both the trials and observational studies search strategies with study design filters. For trials, the Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects via Ovid were also searched. All databases were searched from January 2000 to November 26, 2019. Studies published before 2000 were captured from the grey literature of national obstetrics and gynaecology specialty societies, luminary specialty journals, and bibliographic searching. A formal process for the systematic review was undertaken for this update, as described in the systematic review manuscript published separately.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the SOGC's modified GRADE approach. See Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

The intended users of this guideline include prenatal care providers such as obstetricians, midwives, family physicians, emergency room physicians, and residents, as well as registered nurses and nurse practitioners.

TWEETABLE ABSTRACT

An updated Canadian guideline for prevention of Rh D alloimmunization addresses D variants, cffDNA for fetal Rh type, and updates recommendations on timing of RhIG administration.

SUMMARY STATEMENTS

RECOMMENDATIONS.

py_ped_sim - A flexible forward genetic simulator for complex family pedigree analysis

Background

Large-scale family pedigrees are commonly used across medical, evolutionary, and forensic genetics. These pedigrees are tools for identifying genetic disorders, tracking evolutionary patterns, and establishing familial relationships via forensic genetic identification. However, there is a lack of software to accurately simulate different pedigree structures along with genomes corresponding to those individuals in a family pedigree. This limits simulation-based evaluations of methods that use pedigrees.

Results

We have developed a python command-line-based tool called py_ped_sim that facilitates the simulation of pedigree structures and the genomes of individuals in a pedigree. py_ped_sim represents pedigrees as directed acyclic graphs, enabling conversion between standard pedigree formats and integration with the forward population genetic simulator, SLiM. Notably, py_ped_sim allows the simulation of varying numbers of offspring for a set of parents, with the capacity to shift the distribution of sibship sizes over generations. We additionally add simulations for events of misattributed paternity, which offers a way to simulate half-sibling relationships. We validated the accuracy of our software by simulating genomes onto diverse family pedigree structures, showing that the estimated kinship coefficients closely approximated expected values.

Conclusions

py_ped_sim is a user-friendly and open-source solution for simulating pedigree structures and conducting pedigree genome simulations. It empowers medical, forensic, and evolutionary genetics researchers to gain deeper insights into the dynamics of genetic inheritance and relatedness within families.

One versus two biological parents with mental disorders: Relationship to educational attainment in the next generation

BACKGROUND

Both maternal and, separately, paternal mental illness are associated with diminished academic attainment among children. However, the differential impacts of diagnostic type and degree of parental burden (e.g. one v. both parents affected) on these functional outcomes are unknown.

METHODS

Using the Swedish national patient (NPR) and multi-generation (MGR) registers, 2 226 451 children (1 290 157 parental pairs), born 1 January 1973-31 December 1997, were followed through 31 December 2013. Diagnostic status of all cohort members was defined for eleven psychiatric disorders, and families classed by exposure: (1) parents affected with any disorder, (2) parents affected with a disorder group (e.g. neuropsychiatric disorders), and (3) parents affected with a specific disorder (e.g. ADHD). Pairs were further defined as 'unaffected,' 'single-affected,', or 'dual-affected.' Among offspring, the study evaluated fulfillment of four academic milestones, from compulsory (primary) school through University (college). Sensitivity analyses considered the impact of child's own mental health, as well as parental education, on main effects.

RESULTS

Marked reductions in the odds of achievement were observed, emerging at the earliest levels of schooling for both single-affected [adjusted odds ratio (aOR), 0.50; 95% CI 0.49-0.51] and dual-affected (aOR 0.29, 95% CI 0.28-0.30) pairs and persisting thereafter [aOR range (single), 0.52-0.65; aOR range (dual), 0.30-0.40]. This pattern was repeated for analyses within diagnosis/diagnostic group. Main results were robust to adjustment for offspring mental health and parent education level.

CONCLUSIONS

Parental mental illness is associated with profound reductions in educational attainment in the subsequent generation, with children from dual-affected families at uniquely high risk.

Who's your daddy? An ethical argument for disclosure to donor conceived children

To our knowledge, there have been few discussions in the andrology literature regarding the ethics of disclosure to donor conceived children. Our goal in this paper is to summarize the main reasons in favor of disclosure to engender more conversations about the ethics of donor conception in andrology circles. Specifically, we argue (1) transparency regarding gamete donation upholds the ethical principle of beneficence by improving the psychological health of donor conceived children; and (2) based on the ethical principle of autonomy, donor conceived children should have the right to know their donor status.

Performance of single-gene noninvasive prenatal testing for autosomal recessive conditions in a general population setting

OBJECTIVE

Carrier screening with reflex to single-gene noninvasive prenatal testing (sgNIPT) is an alternative approach for identifying pregnancies at risk for inherited autosomal recessive conditions without the need for a sample from the reproductive partner. This study is the largest clinical validation of this approach in a general population setting.

METHODS

The clinical performance of carrier screening with reflex to sgNIPT for cystic fibrosis, spinal muscular atrophy, alpha thalassemias, and beta hemoglobinopathies was assessed by collecting pregnancy outcome data on patients who underwent this testing and comparing the neonatal outcome to the assay-predicted fetal risk.

RESULTS

Of 42,067 pregnant individuals who underwent screening, 7538 carriers (17.9%) had reflex sgNIPT, and neonatal or fetal outcomes were obtained for 528 cases, including 25 affected pregnancies. Outcomes demonstrated high concordance with sgNIPT, for example, all pregnancies with 9 in 10 personalized fetal risk results were affected (positive predictive value (PPV) of 100% for the sub-group) and the sgNIPT assay showed a sensitivity of 96.0% (95% CI: 79.65%-99.90%), specificity of 95.2% (95% CI: 92.98%-96.92%), average PPV of 50.0% (95% CI: 35.23%-64.77%), and negative predictive value (NPV) of 99.8% (95% CI: 98.84%-99.99%). The end-to-end performance of carrier screening with reflex to sgNIPT was calculated to have a sensitivity of 92.4% and specificity of 99.9%, which are unaffected by partner carrier screening or misattributed paternity unlike a traditional carrier screening workflow, which has a 35% sensitivity and a maximum of 25% PPV (1 in 4) in a real-life setting.

CONCLUSION

This study builds upon earlier findings to confirm that carrier testing with reflex to sgNIPT is highly accurate for general population screening. Given this high accuracy and an NPV of 99.8%, this workflow should be considered as an option for most of the general pregnant population. When the biological partner sample is unavailable, this workflow should be recommended as the first-line approach.

Parent-Offspring Associations in Body Composition: Findings From the Southampton Women's Survey Prospective Cohort Study

CONTEXT

Children born to parents who are overweight or obese have a high risk of adult obesity, but it is unclear if transgenerational associations relating to unfavorable body composition differ by parent.

OBJECTIVE

To examine differential mother-offspring and father-offspring associations in body composition in early childhood.

METHODS

A total of 240 mother-father-offspring trios from a prospective UK population-based pre-birth cohort (Southampton Women's Survey) were included for anthropometry and dual-energy x-ray absorptiometry assessment of whole-body-less-head body composition in the offspring at 3 different ages (4, 6-7, and 8-9 years) and in the mother and father at the 8- to 9-year offspring visit. Associations were assessed using linear regression adjusting for the other parent.

RESULTS

Positive associations between mother-daughter body mass index (BMI) and fat mass were observed at ages 6 to 7 (BMI: β = .29 SD/SD, 95% CI = .10, .48; fat mass β = .27 SD/SD, 95% CI = .05, .48) and 8 to 9 years (BMI: β = .33 SD/SD, 95% CI = .13, .54; fat mass β = .31 SD/SD, 95% CI = .12, .49), with similar associations at age 4 years but bounding the 95% CI. The mother-son, father-son, and father-daughter associations for BMI and fat mass were weaker at each of the ages studied.

CONCLUSION

A strong association between the fat mass of mothers and their daughters but not their sons was observed. In contrast, father-offspring body composition associations were not evident. The dimorphic parent-offspring effects suggest particular attention should be given to early prevention of unfavorable body composition in girls born to mothers with excess adiposity.

Lynch syndrome cancer vaccines: A roadmap for the development of precision immunoprevention strategies

Hereditary cancer syndromes (HCS) account for 5~10% of all cancer diagnosis. Lynch syndrome (LS) is one of the most common HCS, caused by germline mutations in the DNA mismatch repair (MMR) genes. Even with prospective cancer surveillance, LS is associated with up to 50% lifetime risk of colorectal, endometrial, and other cancers. While significant progress has been made in the timely identification of germline pathogenic variant carriers and monitoring and early detection of precancerous lesions, cancer-risk reduction strategies are still centered around endoscopic or surgical removal of neoplastic lesions and susceptible organs. Safe and effective cancer prevention strategies are critically needed to improve the life quality and longevity of LS and other HCS carriers. The era of precision oncology driven by recent technological advances in tumor molecular profiling and a better understanding of genetic risk factors has transformed cancer prevention approaches for at-risk individuals, including LS carriers. MMR deficiency leads to the accumulation of insertion and deletion mutations in microsatellites (MS), which are particularly prone to DNA polymerase slippage during DNA replication. Mutations in coding MS give rise to frameshift peptides (FSP) that are recognized by the immune system as neoantigens. Due to clonal evolution, LS tumors share a set of recurrent and predictable FSP neoantigens in the same and in different LS patients. Cancer vaccines composed of commonly recurring FSP neoantigens selected through prediction algorithms have been clinically evaluated in LS carriers and proven safe and immunogenic. Preclinically analogous FSP vaccines have been shown to elicit FSP-directed immune responses and exert tumor-preventive efficacy in murine models of LS. While the immunopreventive efficacy of "off-the-shelf" vaccines consisting of commonly recurring FSP antigens is currently investigated in LS clinical trials, the feasibility and utility of personalized FSP vaccines with individual HLA-restricted epitopes are being explored for more precise targeting. Here, we discuss recent advances in precision cancer immunoprevention approaches, emerging enabling technologies, research gaps, and implementation barriers toward clinical translation of risk-tailored prevention strategies for LS carriers. We will also discuss the feasibility and practicality of next-generation cancer vaccines that are based on personalized immunogenic epitopes for precision cancer immunoprevention.

Age-related methylation changes in the human sperm epigenome

Advanced paternal age is associated with increased risks for reproductive and offspring medical problems. Accumulating evidence suggests age-related changes in the sperm epigenome as one underlying mechanism. Using reduced representation bisulfite sequencing on 73 sperm samples of males attending a fertility center, we identified 1,162 (74%) regions which were significantly (FDR-adjusted) hypomethylated and 403 regions (26%) being hypermethylated with age. There were no significant correlations with paternal BMI, semen quality, or ART outcome. The majority (1,152 of 1,565; 74%) of age-related differentially methylated regions (ageDMRs) were located within genic regions, including 1,002 genes with symbols. Hypomethylated ageDMRs were closer to transcription start sites than hypermethylated DMRs, half of which reside in gene-distal regions. In this and conceptually related genome-wide studies, so far 2,355 genes have been reported with significant sperm ageDMRs, however most (90%) of them in only one study. The 241 genes which have been replicated at least once showed significant functional enrichments in 41 biological processes associated with development and the nervous system and in 10 cellular components associated with synapses and neurons. This supports the hypothesis that paternal age effects on the sperm methylome affect offspring behaviour and neurodevelopment. It is interesting to note that sperm ageDMRs were not randomly distributed throughout the human genome; chromosome 19 showed a highly significant twofold enrichment with sperm ageDMRs. Although the high gene density and CpG content have been conserved, the orthologous marmoset chromosome 22 did not appear to exhibit an increased regulatory potential by age-related DNA methylation changes.

Maternal carrier screening with single-gene NIPS provides accurate fetal risk assessments for recessive conditions

PURPOSE

The purpose of this study was to evaluate the clinical performance of carrier screening for cystic fibrosis, hemoglobinopathies, and spinal muscular atrophy with reflex single-gene noninvasive prenatal screening (sgNIPS), which does not require paternal carrier screening.

METHODS

An unselected sample of 9151 pregnant individuals from the general US pregnant population was screened for carrier status, of which 1669 (18.2%) were identified as heterozygous for one or more pathogenic variants and reflexed to sgNIPS. sgNIPS results were compared with newborn outcomes obtained from parent survey responses or provider reports for a cohort of 201 pregnancies.

RESULTS

Overall, 98.7% of pregnant individuals received an informative result (no-call rate = 1.3%), either a negative carrier report or, if identified as heterozygous for a pathogenic variant, a reflex sgNIPS report. In the outcomes cohort, the negative predictive value of sgNIPS was 99.4% (95% CI = 96.0%-99.9%) and average positive predictive value (PPV) of sgNIPS was 48.3% (95% CI = 36.1%-60.1%). Importantly, personalized PPVs accurately reflected the percentage of affected pregnancies in each PPV range, and all pregnancies with a sgNIPS fetal risk of >9 in 10 (90% PPV) were affected.

CONCLUSION

Although traditional carrier screening is most effective when used to assess reproductive risk before pregnancy, more than 95% of the time it is pursued during a pregnancy and is complicated by incomplete uptake of paternal carrier screening (<50%) and misattributed paternity (∼10%). Even in an idealized setting, when both partners have carrier screening, the maximum risk for having an affected pregnancy is 1 in 4 (equivalent of a 25% PPV). Carrier screening with sgNIPS during pregnancy is an alternative that does not require a paternal sample and provides accurate fetal risk in a timely manner that can be used for prenatal counseling and pregnancy management.

Minor impact on fertility in men with inflammatory bowel disease: A National Cohort Study from Sweden

BACKGROUND AND AIMS

Onset of inflammatory bowel disease (IBD) in men is most common during childbearing age, but little is known about the impact on fertility. Previous studies of fertility in men were small, which justifies this large nation-based registry study.

METHODS

Fertility was assessed in a national cohort of men with IBD aged 15-44 years in 1964-2014, identified from the Swedish National Patient Register, and in a reference cohort matched for age and place of residence (ratio 1:5). Information about childbirths was found in the Swedish Multi-Generation Register. Patients with indeterminate colitis or inconsistent IBD coding were classified as IBD-unclassified (IBD-U).

RESULTS

The cohorts included 29,104 men with IBD and 140,901 matched individuals. IBD patients had a lower fertility rate (number of births per 1000 person years) compared with the matched individuals; 1.28 (SD 1.27) versus 1.35 (SD 1.31; p < 0.001). Fertility was somewhat impaired in all IBD subtypes compared with the matched cohort; ulcerative colitis (UC) (hazard ratio [HR] 0.93, 95% CI 0.91-0.96), Crohn's disease (CD) (HR 0.95, 95% CI 0.92-0.98) and IBD-U 0.92, 95% CI 0.89-0.95. The cumulated total parity and the parity progression were also decreased for all IBD subtypes. Within the IBD cohort disease severity, intensity of medical treatment (CD) and bowel surgery (IBD-U) were further associated with impaired fertility.

CONCLUSIONS

This nationwide cohort study shows only slightly impaired fertility in men with IBD.

Resemblance Reporting on Children: Sisters Are More Proactive than Brothers

The asymmetric grandparental investment in humans may ultimately be explained by the paternity uncertainty hypothesis. The proximate mechanisms leading to grandparental bias in investment in grandchildren are, however, unclear. In a study of 233 males and females with an opposite sexed sibling, we examined whether comments on resemblance regarding one’s own child, or one’s sibling’s child, changed in frequency after both siblings became parents. We found that comments among siblings on resemblance of children occurred more frequently after both became parents, compared to when only one of the siblings had children, suggesting that resemblance descriptions may become more important after both siblings have children. Furthermore, and in line with the suggestion that mothers may mentally exploit the alloparenting environment by holding a stronger belief about resemblance, brothers reported that their sisters commented on resemblance concerning their own child more often and more intensely. Additionally, sisters corroborated this finding by self-reporting that they were the most proactive during resemblance descriptions of their brothers’ child. Thus, sisters might, through more frequent voicing of stronger opinions on parent–child resemblance than their brothers, influence alloparents’ perception of resemblance to their children and thus influence alloparental investments.

Birth order differences in education originate in postnatal environments

Siblings share many environments and much of their genetics. Yet, siblings turn out different. Intelligence and education are influenced by birth order, with earlier-born siblings outperforming later-borns. We investigate whether birth order differences in education are caused by biological differences present at birth, that is, genetic differences or in utero differences. Using family data that spans two generations, combining registry, survey, and genotype information, this study is based on the Norwegian Mother, Father, and Child Cohort Study (MoBa). We show that there are no genetic differences by birth order as captured by polygenic scores (PGSs) for educational attainment. Earlier-born have lower birth weight than later-born, indicating worse uterine environments. Educational outcomes are still higher for earlier-born children when we adjust for PGSs and in utero variables, indicating that birth order differences arise postnatally. Finally, we consider potential environmental influences, such as differences according to maternal age, parental educational attainment, and sibling genetic nurture. We show that birth order differences are not biological in origin, but pinning down their specific causes remains elusive.

Title: Noninvasive prenatal testing of hereditary colorectal cancer syndromes using cell-free DNA in maternal plasma

OBJECTIVE

This study aimed to establish a practical protocol for early noninvasive prenatal testing (NIPT) for fetuses at risk of Peutz-Jeghers syndrome (PJS) or familial adenomatous polyposis (FAP), two classical types of hereditary colorectal cancer syndromes, for risk evaluation and whole-life monitoring.

METHOD

Target enrichment was performed using hybridization probes coordinating the STK11 gene region and APC gene region, with 1,458 highly heterozygous SNPs included. Semitarget amplification random sequencing was used for large fragment deletion detection. For relative haplotype dosage (RHDO) analysis, haplotype construction was performed by SHAPEIT software, the CBS algorithm was used for recombination event calculation, and Bayes factor was used for the determination of whether the fetus was affected.

RESULTS

Haplotypes were successfully constructed in the nine recruited families with different pedigree characteristics, and the results for the RHDO analysis were consistent with the amniocentesis sampling detection results. The cell-free fetal DNA fraction can be detected as low as 2% in maternal plasma.

CONCLUSION

This is the first NIPT assay on hereditary colorectal cancer syndromes based upon RHDO analysis. This article is protected by copyright. All rights reserved.

Comparison of Bioinformatics Approaches for Fetal Microdeletions and Monogenic Variations Estimation in Non-invasive Prenatal Testing

Prenatal testing provides crucial information about the health status of fetuses as well as recommending better treatment. For the past decades, prenatal testing using chorionic villus sampling and amniocentesis were the two majorly used forms of invasive prenatal diagnostic approaches. However, to facilitate prenatal testing without causing any danger to the fetus, the noninvasive prenatal diagnostic method, which uses circulating cell-free deoxyribonucleic acid (DNA), has become a suitable method of prenatal diagnosis. This review discusses the recent bioinformatics approaches used for analyzing fetal DNA concentration.

The frequency of misattributed paternity in Sweden is low and decreasing: A nationwide cohort study

BACKGROUND

The occurrence of misattributed paternity has consequences throughout society with implications ranging from inheritance and royal succession to transplantation. However, its frequency in Sweden is unknown.

OBJECTIVE

To estimate the contemporary frequency of misattributed paternity in Sweden.

METHODS

The study was based on nationwide ABO blood group data and a nationwide register of familial relationships in Sweden. These data were analysed using both a frequentist Poisson model and the Bayesian Gibbs model. The conduct of the study was approved by the regional ethics committee in Stockholm, Sweden (reference numbers 2018/167-31 and 2019-04656).

RESULTS

Nearly two million mother-father-offspring family units were included. Overall, the frequency of misattributed paternity was estimated at 1.7% in both models. Misattributed paternity was more common among parents with low educational levels, and has decreased over time to a current 1%.

CONCLUSIONS

The misattributed paternity rate is similar to the rates in other West European populations. Apart from widespread societal implications, studies on heritability may consider misattributed paternity as a minor source of error.

Misattributed parentage identified through diagnostic exome sequencing: Frequency of detection and reporting practices

Access to genetic testing, namely, diagnostic exome sequencing (DES), has significantly improved, subsequently increasing the likelihood of discovering incidental findings, such as misattributed relationships and specifically misattributed parentage (MP). Until the recently published ACMG statement, there had been no consensus for laboratories and clinicians to follow when addressing such findings. Family-based genomic testing is valuable for accurate variant interpretation but has the potential to uncover misattributed familial relationships. Here, we present the first published data on the frequency of MP identified through DES at a clinical laboratory. We also investigated clinicians' decisions on how to proceed with analysis, reporting, and disclosure. A database of 6,752 families who underwent parent-proband ('trio') DES was retrospectively reviewed for molecular identification of MP and clinicians' MP disclosure decisions. Among 6,752 trios, 39 cases of MP were detected (0.58%). Non-paternity was detected in all cases, and in one instance, non-maternity was also identified. All clinicians decided to proceed by omitting the MP individual from the analysis. Clinicians chose to proceed with duo analysis (87.2%), modify information on the report (74.4%), and communicate MP results to the mother (71.8%), suggesting a trend toward not disclosing to the putative father or proband. The data show that trio DES involves a chance of detecting MP and that clinician disclosure practices do not appear to routinely include direct disclosure to the putative father. MP identified in our parent-proband trios sent in for DES is lower than the reported frequency of MP in the general population due in part to ascertainment bias as families with known or suspected MP are presumably less likely to pursue trio testing. These data may inform laboratory policies and clinician practices for addressing incidental findings such as MP.

Mortality Among Parents of Children With Major Congenital Anomalies

BACKGROUND

A mother whose child has a chronic condition, such as a major congenital anomaly, often experiences poorer long-term health, including earlier mortality. Little is known about the long-term health of fathers of infants with a major congenital anomaly.

METHODS

In this population-based prospective cohort study, we used individual-linked Danish registry data. Included were all mothers and fathers with a singleton infant born January 1, 1986, to December 31, 2015. Cox proportional hazards regression was used to generate hazard ratios for all-cause and cause-specific mortality among mothers and fathers whose infant had an anomaly and fathers of unaffected infants, relative to mothers of unaffected infants (referent), adjusted for child's year of birth, parity, parental age at birth, parental comorbidities, and sociodemographic characteristics.

RESULTS

In total, 20 952 of 965 310 mothers (2.2%) and 20 655 of 951 022 fathers (2.2%) had an infant with a major anomaly. Median (interquartile range) of parental follow-up was 17.9 (9.5 to 25.5) years. Relative to mothers of unaffected infants, mothers of affected infants had adjusted hazard ratios (aHRs) of death of 1.20 (95% confidence interval [CI]: 1.09 to 1.32), fathers of unaffected infants had intermediate aHR (1.62, 95% CI: 1.59 to 1.66), and fathers of affected infants had the highest aHR (1.76, 95% CI: 1.64 to 1.88). Heightened mortality was primarily due to cardiovascular and endocrine/metabolic diseases.

CONCLUSIONS

Mothers and fathers of infants with a major congenital anomaly experience an increased risk of mortality, often from preventable causes. These findings support including fathers in interventions to support the health of parental caregivers.

Genetic and environmental sources of familial coaggregation of obsessive-compulsive disorder and suicidal behavior: a population-based birth cohort and family study

Obsessive-compulsive disorder (OCD) is associated with high risk of suicide. It is yet unknown whether OCD and suicidal behaviors coaggregate in families and, if so, what are the mechanisms underlying this coaggregation. In a population-based birth cohort and family study, we linked individuals born in Sweden in 1967-2003 (n = 3,594,181) to their parents, siblings, and cousins, and collected register-based diagnoses of OCD, suicide attempts, and deaths by suicide and followed them until December 31, 2013. We also applied quantitative genetic modeling to estimate the contribution of genetic and environmental factors to the familial coaggregation of OCD and suicidal behavior. An elevated risk of suicide attempts was observed across all relatives of individuals with OCD, increasing proportionally to the degree of genetic relatedness, with odds ratios (OR) ranging from 1.56 (95% confidence interval (CI) 1.49-1.63) in parents to 1.11 (95% CI 1.07-1.16) in cousins. The risk of death by suicide also increased alongside narrowing genetic distance, but was only significant in parents (OR 1.55; 95% CI 1.40-1.72) and full siblings (OR 1.80; 95% CI 1.43-2.26) of individuals with OCD. Familial coaggregation of OCD and suicide attempts was explained by additive genetic factors (60.7%) and non-shared environment (40.4%), with negligible contribution of shared environment. Similarly, familial coaggregation with death by suicide was attributed to additive genetics (65.8%) and nonshared environment (34.2%). Collectively, these observations indicate that OCD and suicidal behaviors coaggregate in families largely due to genetic factors. The contribution of unique environment is also considerable, providing opportunities to target high-risk groups for prevention and treatment.

Paternal prescription medication before conception: A retrospective cohort study of all births in Denmark 1997-2017

AIM

To study what medication fathers are being prescribed in the months preceding conception.

METHODS

A retrospective cohort study of Danish national registries, comprising all births in Denmark 1997-2017 (1.3 million births). Time trends and absolute levels of paternal prescription medication in the 6 months prior to conception were assessed. While all medications were examined (N = 1335), we focused on the main medication groups, medications that have increased in use over time, and medications for which previous evidence exists of an effect on sperm quality.

RESULTS

The average number of prescriptions increased over the study period (from 0.75 prescriptions to 0.82 per birth). Polypharmacy (three or more prescriptions) increased from less than 8% to 10% of fathers. The use of pain medication, proton-pump inhibitors, selective serotonin reuptake inhibitors and some inhalants have all increased markedly over the last 20 years.

CONCLUSIONS

Potential harm to the offspring done by paternal medication may present an increasing problem. As paternal medication exposure is increasing, examination of generational effects, such as major birth defects, is necessary.

Massively Parallel Sequencing for Rare Genetic Disorders: Potential and Pitfalls

There have been two major eras in the history of gene discovery. The first was the era of linkage analysis, with approximately 1,300 disease-related genes identified by positional cloning by the turn of the millennium. The second era has been powered by two major breakthroughs: the publication of the human genome and the development of massively parallel sequencing (MPS). MPS has greatly accelerated disease gene identification, such that disease genes that would have taken years to map previously can now be determined in a matter of weeks. Additionally, the number of affected families needed to map a causative gene and the size of such families have fallen: de novo mutations, previously intractable by linkage analysis, can be identified through sequencing of the parent-child trio, and genes for recessive disease can be identified through MPS even of a single affected individual. MPS technologies include whole exome sequencing (WES), whole genome sequencing (WGS), and panel sequencing, each with their strengths. While WES has been responsible for most gene discoveries through MPS, WGS is superior in detecting copy number variants, chromosomal rearrangements, and repeat-rich regions. Panels are commonly used for diagnostic purposes as they are extremely cost-effective and generate manageable quantities of data, with no risk of unexpected findings. However, in instances of diagnostic uncertainty, it can be challenging to choose the right panel, and in these circumstances WES has a higher diagnostic yield. MPS has ethical, social, and legal implications, many of which are common to genetic testing generally but amplified due to the magnitude of data (e.g., relationship misattribution, identification of variants of uncertain significance, and genetic discrimination); others are unique to WES and WGS technologies (e.g., incidental or secondary findings). Nonetheless, MPS is rapidly translating into clinical practice as an extremely useful part of the clinical armamentarium.

The ethics and logistics of field-based genetic paternity studies

The rapidly decreasing costs of generating genetic data sequencing and the ease of new DNA collection technologies have opened up new opportunities for anthropologists to conduct field-based genetic studies. An exciting aspect of this work comes from linking genetic data with the kinds of individual-level traits evolutionary anthropologists often rely on, such as those collected in long-term demographic and ethnographic studies. However, combining these two types of data raises a host of ethical questions related to the collection, analysis and reporting of such data. Here we address this conundrum by examining one particular case, the collection and analysis of paternity data. We are particularly interested in the logistics and ethics involved in genetic paternity testing in the localized settings where anthropologists often work. We discuss the particular issues related to paternity testing in these settings, including consent and disclosure, consideration of local identity and beliefs and developing a process of continued community engagement. We then present a case study of our own research in Namibia, where we developed a multi-tiered strategy for consent and community engagement, built around a double-blind procedure for data collection, analysis and reporting.

Paternity testing in anthropology raises ethical and methodological issues. We summarize these and describe a novel double-blind method used in our work.

A novel high-throughput molecular counting method with single base-pair resolution enables accurate single-gene NIPT

Next-generation DNA sequencing is currently limited by an inability to accurately count the number of input DNA molecules. Molecular counting is particularly needed when accurate quantification is required for diagnostic purposes, such as in single gene non-invasive prenatal testing (sgNIPT) and liquid biopsy. We developed Quantitative Counting Template (QCT) molecular counting to reconstruct the number of input DNA molecules using sequencing data. We then used QCT molecular counting to develop sgNIPTs of sickle cell disease, cystic fibrosis, spinal muscular atrophy, alpha-thalassemia, and beta-thalassemia. The analytical sensitivity and specificity of sgNIPT was >98% and >99%, respectively. Validation of sgNIPTs was further performed with maternal blood samples collected during pregnancy, and sgNIPTs were 100% concordant with newborn follow-up.

Genomic testing in pediatric epilepsy

Genomic testing has become routine in the diagnosis and management of pediatric patients with epilepsy. In a single test, hundreds to thousands of genes are examined for DNA changes that may not only explain the etiology of the patient's condition but may also inform management and seizure control. Clinical genomic testing has been in clinical practice for less than a decade, and because of this short period of time, the appropriate clinical use and interpretation of genomic testing is still evolving. Compared to the previous era of single-gene testing in epilepsy, which yielded a diagnosis in <5% of cases, many clinical genomic studies of epilepsy have demonstrated a clinically significant diagnosis in 30% or more of patients tested. This review will examine key studies of the past decade and indicate the clinical scenarios in which genomic testing should be considered standard of care.

The impact of incorrectly recorded parentage on inferred genotypes over multiple generations

The absence of selective pressure against recessive deleterious mutations in the heterozygous state means that virtually every individual will carry several such mutations which have arisen over time. The inflation in frequency of a few of these mutations due to selective processes during domestication and breed formation have left modern domestic dog breeds with a high burden of genetic disease due to mutations at single genes. This has stimulated research into the causal mutations, and a consequential market in DNA tests, which enable breeders to distinguish heterozygotes from wild type homozygotes and determine pairings that will avoid producing diseased progeny. The genotypes of progeny of parents with known genotypes themselves may in some cases be definitively inferred. Importantly, two parents homozygous for non-disease causing alleles, will produce progeny with the same genotype, which may be assigned to the offspring (e.g. as ‘hereditary clear’) without the need for further testing.

However, the veracity of assigned genotypes is dependent on the parentage being recorded without error, which is not the case in most species. Simulations presented here demonstrate that a modest rate of false paternity can result in a notable proportion of ‘hereditary clear’ assignments being false when ‘hereditary clear’ status is assigned across a number of generations (error rates exceeding 5% after 6 generations with a disease causing mutation frequency of 0.2). Erroneous assignment of ‘hereditary clear’ genotypes risks the production of puppies with the very disease for which a DNA test is available allowing avoidance. In light of these findings and to reduce the risks of producing puppies destined to be affected by such diseases, the Kennel Club has determined to limit the assignment of ‘hereditary clear’ status of registered dogs to 2 generations, with effect from January 2022.

Parental age and the risk of childhood acute myeloid leukemia: results from the Childhood Leukemia International Consortium

BACKGROUND

Parental age has been associated with several childhood cancers, albeit the evidence is still inconsistent.

AIM

To examine the associations of parental age at birth with acute myeloid leukemia (AML) among children aged 0-14 years using individual-level data from the Childhood Leukemia International Consortium (CLIC) and non-CLIC studies.

MATERIAL/METHODS

We analyzed data of 3182 incident AML cases and 8377 controls from 17 studies [seven registry-based case-control (RCC) studies and ten questionnaire-based case-control (QCC) studies]. AML risk in association with parental age was calculated using multiple logistic regression, meta-analyses, and pooled-effect estimates. Models were stratified by age at diagnosis (infants <1 year-old vs. children 1-14 years-old) and by study design, using five-year parental age increments and controlling for sex, ethnicity, birthweight, prematurity, multiple gestation, birth order, maternal smoking and education, age at diagnosis (cases aged 1-14 years), and recruitment time period.

RESULTS

Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) derived from RCC, but not from the QCC, studies showed a higher AML risk for infants of mothers ≥40-year-old (OR = 6.87; 95% CI: 2.12-22.25). There were no associations observed between any other maternal or paternal age group and AML risk for children older than one year.

CONCLUSIONS

An increased risk of infant AML with advanced maternal age was found using data from RCC, but not from QCC studies; no parental age-AML associations were observed for older children.

Association between parental autoimmune disease and atopic dermatitis in their offspring: a matched case-control study

BACKGROUND

Atopic dermatitis (AD) is associated with many autoimmune diseases, in part due to overlapping genetic risk loci. While parental atopic disease is an important risk for AD in the offspring, little is known on the putative associations between parental autoimmune disease and AD in their children.

MATERIALS AND METHODS

All children born between 1996 and 2011 who received a diagnosis of AD in the hospital system before their fifth birthday were matched 1 : 10 with children from the general population. Maternal and paternal autoimmune diseases were assessed using registry-based data. Conditional logistic regression was performed on the relationships between parental autoimmune diseases and AD in their children.

RESULTS

A total of 8589 children with AD were matched with controls. One or more autoimmune disease was identified in 5.89% (506/8589) of mothers to AD children and 3.67% (315/8589) of fathers to AD children compared to 4.85% (4163/85 890) and 3.28% (2816/85 890) in parents of control children. Maternal autoimmune disease but not paternal autoimmune disease was associated with AD in the offspring (odds ratio [OR] 1.20 [95% confidence interval (CI) 1.20-1.32] and OR 1.08 [0.96-1.22], respectively), Two or more maternal autoimmune diseases, maternal dermatologic autoimmune disease and maternal digestive autoimmune disease were all also associated with AD development in her children (1.96 [95% CI 1.36-2.84], OR 1.60 [95% CI 1.24-2.07] and OR 1.24 [95% CI 1.06-1.45], respectively).

CONCLUSIONS

The risk of AD is influenced by many factors including atopy status and filaggrin gene mutations. In this matched case-control study, maternal autoimmune disease was associated with AD diagnosis in the offspring. Maternal dermatologic and digestive autoimmune diseases were most closely associated with subsequent AD diagnosis in the offspring.

When genomic medicine reveals misattributed genetic relationships-the debate about disclosure revisited

PURPOSE

Accidental discovery of misattributed parentage is an age-old problem in clinical medicine, but the ability to detect it routinely has increased recently as a result of high-throughput DNA sequencing technologies coupled with family sequencing studies. Problems arise at the clinical-research boundary, where policies and consent forms guaranteeing nondisclosure may conflict with standard clinical care.

METHODS

To examine the challenges of managing misattributed parentage within hybrid translational research studies, we used a case study of a developmentally delayed child with a candidate variant found through a large-scale trio genome sequencing study in which data from unrelated samples were routinely excluded.

RESULTS

We discuss whether genetic parentage should be explicitly confirmed during clinical validation, thus giving greater weight to the diagnosis according to American College of Medical Genetics and Genomics variant interpretation guidelines, and what tensions this approach would create.

CONCLUSION

We recommend that the possibility of finding and disclosing misattributed parentage should be addressed during the consent or pretest counseling process, and that clinical relevance should determine whether or not to disclose results in the clinic. This proposition has implications for research governance, and implies that it may not always be possible to uphold nondisclosure commitments as investigations move from research to clinical care.

Do mothers also "manipulate" grandparental care?

Paternity uncertainty has proven to be a robust ultimate hypothesis for predicting the higher investment in grandchildren observed among maternal grandparents compared to that of the paternal grandparents. Yet the proximate mechanisms for generating such preferred biases in grandparental investment remain unclear. Here we address two different questions for better understanding the proximate mechanisms leading to the observed bias in grandparental investments: (i) is there a larger emphasis on resemblance descriptions (between grandchildren and grandparent) among daughters than among sons, and (ii) do mothers really believe that their offspring more resemble their parents, that is, the children's grandparents, than fathers do? From questioning grandparents, we find that daughters more often and more intensely than sons express opinions about grandchild-grandparent resemblance. Moreover, daughters also seem to believe that their children more resemble their grandmother than sons do. The latter is, however, not the case for beliefs about children's resemblance to grandfathers. In sum, our results suggest that even in a population of Norwegians, strongly influenced by ideas concerning gender equality, there exist a sexual bias among parents in opinions and descriptions about grandchild-grandparent resemblance. This resemblance bias, which echoes that of mothers biasing resemblance descriptions of newborns to putative fathers, does not seem to represent a conscious manipulation. Yet it could be instrumental for influencing grandparental investments. We believe that a "manipulative mother hypothesis" might parsimoniously account for many of the results relating to biased alloparenting hitherto not entirely explained by "the paternity uncertainty hypothesis."

A 472-SNP panel for pairwise kinship testing of second-degree relatives

Kinship testing based on genetic markers, as forensic short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs), has valuable practical applications. Paternity and first-degree relationship can be accurately identified by current commonly-used forensic STRs and reported SNP markers. However, second-degree and more distant relationships remain challenging. Although ∼10⁵-10⁶ SNPs can be used to estimate relatedness of higher degrees, genome-wide genotyping and analysis may be impractical for forensic use. With rapid growth of human genome data sets, it is worthwhile to explore additional markers, especially SNPs, for kinship analysis. Here, we reported an autosomal SNP panel consisted of 342 SNP selected from >84 million SNPs and 131 SNPs from previous systems. We genotyped these SNPs in 136 Chinese individuals by multiplex amplicon Massively Parallel Sequencing, and performed pairwise gender-independent kinship testing. The specificity and sensitivity of these SNPs to distinguish second-degree relatives and the unrelated was 99.9% and 100%, respectively, compared with 53.7% and 99.9% of 19 commonly-used forensic STRs. Moreover, the specificity increased to 100% by the combined use of these STRs and SNPs. The 472-SNP panel could also greatly facilitate the discrimination among different relationships. We estimated that the power of ∼6.45 SNPs were equivalent to one forensic STR in the scenario of 2nd-degree relative pedigree. Altogether, we proposed a panel of 472 SNP markers for kinship analysis, which could be important supplementary of current forensic STRs to solve the problem of second-degree relative testing.

Paternity tests in Mexico: Results obtained in 3005 cases

National and international reports regarding the paternity testing activity scarcely include information from Mexico and other Latin American countries. Therefore, we report different results from the analysis of 3005 paternity cases analyzed during a period of five years in a Mexican paternity testing laboratory. Motherless tests were the most frequent (77.27%), followed by trio cases (20.70%); the remaining 2.04% included different cases of kinship reconstruction. The paternity exclusion rate was 29.58%, higher but into the range reported by the American Association of Blood Banks (average 24.12%). We detected 65 mutations, most of them involving one-step (93.8% and the remaining were two-step mutations (6.2%) thus, we were able to estimate the paternal mutation rate for 17 different STR loci: 0.0018 (95% CI 0.0005-0.0047). Five triallelic patterns and 12 suspected null alleles were detected during this period; however, re-amplification of these samples with a different Human Identification (HID) kit confirmed the homozygous genotypes, which suggests that most of these exclusions actually are one-step mutations. HID kits with ≥20 STRs detected more exclusions, diminishing the rate of inconclusive results with isolated exclusions (<3 loci), and leading to higher paternity indexes (PI). However, the Powerplex 21 kit (20 STRs) and Powerplex Fusion kit (22 STRs) offered similar PI (p = 0.379) and average number of exclusions (PE) (p = 0.339) when a daughter was involved in motherless tests. In brief, besides to report forensic parameters from paternity tests in Mexico, results describe improvements to solve motherless paternity tests using HID kits with ≥20 STRs instead of one including 15 STRs.