A maternal-effect Padi6 variant causes nuclear and cytoplasmic abnormalities in oocytes, as well as failure of epigenetic reprogramming and zygotic genome activation in embryos.

Maternal inactivation of genes encoding components of the subcortical maternal complex (SCMC) and its associated member, PADI6, generally results in early embryo lethality. In humans, SCMC gene variants were found in the healthy mothers of children affected by multilocus imprinting disturbances (MLID). However, how the SCMC controls the DNA methylation required to regulate imprinting remains poorly defined. We generated a mouse line carrying a Padi6 missense variant that was identified in a family with Beckwith-Wiedemann syndrome and MLID. If homozygous in female mice, this variant resulted in interruption of embryo development at the two-cell stage. Single-cell multiomic analyses demonstrated defective maturation of Padi6 mutant oocytes and incomplete DNA demethylation, down-regulation of zygotic genome activation (ZGA) genes, up-regulation of maternal decay genes, and developmental delay in two-cell embryos developing from Padi6 mutant oocytes but little effect on genomic imprinting. Western blotting and immunofluorescence analyses showed reduced levels of UHRF1 in oocytes and abnormal localization of DNMT1 and UHRF1 in both oocytes and zygotes. Treatment with 5-azacytidine reverted DNA hypermethylation but did not rescue the developmental arrest of mutant embryos. Taken together, this study demonstrates that PADI6 controls both nuclear and cytoplasmic oocyte processes that are necessary for preimplantation epigenetic reprogramming and ZGA.

New insights into oocyte cytoplasmic lattice-associated proteins.

Oocyte maturation and preimplantation embryo development are critical to successful pregnancy outcomes and the correct establishment and maintenance of genomic imprinting. Thanks to novel technologies and omics studies in human patients and mouse models, the importance of the proteins associated with the cytoplasmic lattices (CPLs), highly abundant structures found in the cytoplasm of mammalian oocytes and preimplantation embryos, in the maternal to zygotic transition is becoming increasingly evident. This review highlights the recent discoveries on the role of these proteins in protein storage and other oocyte cytoplasmic processes, epigenetic reprogramming, and zygotic genome activation (ZGA). A better comprehension of these events may significantly improve clinical diagnosis and pave the way for targeted interventions aiming to correct or mitigate female fertility issues and genomic imprinting disorders.

Risk of genetic and epigenetic alteration in children conceived following ART: Is it time to return to nature whenever possible?

Assisted reproductive technology may influence epigenetic signature as the procedures coincide with the extensive epigenetic modification occurring from fertilization to embryo implantation. However, it is still unclear to what extent ART alters the embryo epigenome. In vivo fertilization occurs in the fallopian tube, where a specific and natural environment enables the embryo's healthy development. During this dynamic period, major waves of epigenetic reprogramming, crucial for the normal fate of the embryo, take place. Over the past decade, concerns relating to the raised incidence of epigenetic anomalies and imprinting following ART have been raised by several authors. Epigenetic reprogramming is particularly susceptible to environmental conditions during the periconceptional period; therefore, unphysiological conditions, including ovarian stimulation, in vitro fertilization, embryo culture, cryopreservation of gametes and embryos, parental lifestyle, and underlying infertility, have the potential to contribute to epigenetic dysregulation independently or collectively. This review critically appraises the evidence relating to the association between ART and genetic and epigenetic modifications that may be transmitted to the offspring.

Expanding the clinico-molecular spectrum of Angelman syndrome phenotype with the GABRG3 gene: Evidence from methylation and sequencing studies.

Angelman syndrome (AS) (OMIM#105830) is an imprinting disorder caused due to alterations in the maternal chr 15q11-13 region. Majority of cases can be diagnosed by methylation-specific polymerase chain reaction (MS-PCR) of SNRPN gene and by UBE3A sequencing, however, about 10% of cases with AS phenotype remain undiagnosed. Differential diagnoses of AS can be detected by chromosomal microarray (CMA) and clinical exome sequencing (CES). In this study, 30 cases with AS features were evaluated by MS-PCR, CMA, and CES. SNRPN MS-PCR confirmed AS in eight (26%), CMA and CES diagnosed nine (30%) cases. One case was identified with a novel variant c.1125C > T in GABRG3, located at 15q12 region, which is currently not associated with any syndrome. The GABRG3 gene is also speculated to be imprinted, a MS-PCR assay was designed to confirm its differential parental methylation status. This assay identified another case with altered GABRG3 methylation. The two cases with GABRG3 alteration-sequence change and methylation indicate that GABRG3 may be associated with a subtype of AS or a new related syndrome. Performing GABRG3 MS-PCR and sequencing of a larger group of patients with AS phenotype and normal SNPRN and UBE3A status will help in establishing exact genotype-phenotype correlation.

ImprintSeq, a novel tool to interrogate DNA methylation at human imprinted regions and diagnose multilocus imprinting disturbance.

PURPOSE: Disruptions of genomic imprinting are associated with congenital imprinting disorders (CIDs) and other disease states, including cancer. CIDs are most often associated with altered methylation at imprinted differentially methylated regions (iDMRs). In some cases, multiple iDMRs are affected causing multilocus imprinting disturbances (MLIDs). The availability of accurate, quantitative, and scalable high-throughput methods to interrogate multiple iDMRs simultaneously would enhance clinical diagnostics and research. METHODS: We report the development of a custom targeted methylation sequencing panel that covered most relevant 63 iDMRs for CIDs and the detection of MLIDs. We tested it in 70 healthy controls and 147 individuals with CIDs. We distinguished loss and gain of methylation per differentially methylated region and classified high and moderate methylation alterations. RESULTS: Across a range of CIDs with a variety of molecular mechanisms, ImprintSeq performed at 98.4% sensitivity, 99.9% specificity, and 99.9% accuracy (when compared with previous diagnostic testing). ImprintSeq was highly sensitive for detecting MLIDs and enabled diagnostic criteria for MLID to be proposed. In a child with extreme MLID profile a probable genetic cause was identified. CONCLUSION: ImprintSeq provides a novel assay for clinical diagnostic and research studies of CIDs, MLIDs, and the role of disordered imprinting in human disease states.

Clinical and molecular characterization of patients affected by Beckwith-Wiedemann spectrum conceived through assisted reproduction techniques.

The prevalence of Beckwith-Wiedemann spectrum (BWSp) is tenfold increased in children conceived through assisted reproductive techniques (ART). More than 90% of ART-BWSp patients reported so far display imprinting center 2 loss-of-methylations (IC2-LoM), versus 50% of naturally conceived BWSp patients. We describe a cohort of 74 ART-BWSp patients comparing their features with a cohort of naturally conceived BWSp patients, with the ART-BWSp patients previously described in literature, and with the general population of children born from ART. We found that the distribution of UPD(11)pat was not significantly different in ART and naturally conceived patients. We observed 68.9% of IC2-LoM and 16.2% of mosaic UPD(11)pat in our ART cohort, that strongly differ from the figure reported in other cohorts so far. Since UPD(11)pat likely results from post-fertilization recombination events, our findings allows to hypothesize that more complex molecular mechanisms, besides methylation disturbances, may underlie BWSp increased risk in ART pregnancies. Moreover, comparing the clinical features of ART and non-ART BWSp patients, we found that ART-BWSp patients might have a milder phenotype. Finally, our data show a progressive increase in the prevalence of BWSp over time, paralleling that of ART usage in the last decades.

Novel pathogenic variants in NLRP7, NLRP5, and PADI6 in patients with recurrent hydatidiform moles and reproductive failure.

Recurrent hydatidiform moles (RHMs) are human pregnancies with abnormal embryonic development and hyperproliferating trophoblast. Biallelic mutations in NLRP7 and KHDC3L, members of the subcortical maternal complex (SCMC), explain the etiology of RHMs in only 60% of patients. Here we report the identification of seven functional variants in a recessive state in three SCMC members, five in NLRP7, one in NLRP5, and one in PADI6. In NLRP5, we report the first patient with RHMs and biallelic mutations. In PADI6, the patient had four molar pregnancies, two of which had fetuses with various abnormalities including placental mesenchymal dysplasia and intra-uterine growth restriction, which are features of Beckwith-Wiedemann syndrome and Silver Russell syndrome, respectively. Our findings corroborate recent studies and highlight the common oocyte origin of all these conditions and the continuous spectrum of abnormalities associated with deficiencies in the SCMC genes.

Molecular subtype and growth hormone effects on dysmorphology in Prader-Willi syndrome.

Prader-Willi syndrome (PWS) affects 1/15,000-1/30,000 live births and is characterized by lack of expression of paternally inherited genes on 15q11.2-15q13 caused by paternal deletions, maternal uniparental disomy (UPD), or imprinting defects. Affected individuals have distinct physical features, and growth hormone (GH) deficiency occurs in some individuals with PWS. The aim of this study is to test the hypotheses that (a) individuals with deletions and UPD have different physical and dysmorphic features, (b) individuals treated with GH have different physical and dysmorphic features than those not treated, and (c) GH treatment effects are different for individuals with UPD in comparison to those with deletions. Study participants included 30 individuals with deletions or UPD, who did or did not have GH treatment. Participants' molecular abnormalities were determined by molecular and cytogenetic analysis. Clinical data were obtained by a single dysmorphologist. Individuals with deletions were found to be heavier (p = .001), taller (p = .031), with smaller head circumferences (p = .042) and were more likely to have fair skin and hair than their family members (p = .031, .049, respectively) compared to UPD patients. Females with deletions more commonly had hypoplastic labia minora (p = .009) and clitoris (.030) in comparison to those with UPD. Individuals who received GH in both deletion and UPD groups were taller (p = .004), had larger hands (p = .011) and feet (p = .006) and a trend for a larger head circumference (p = .103). Interestingly, the GH-treated group also had a lower rate of strabismus (esotropia [p = .017] and exotropia [p = .039]). This study showed statistically significant correlations between phenotype and molecular subtypes and also between phenotype and GH treatment.

Genetics of Neonatal Hypoglycaemia.

Hypoglycaemia is the most common metabolic health complication in newborns. Persistent and severe hypoglycaemia in a neonate is correlated with morbidity and could represent an early clinical manifestation of an endocrine or metabolic, genetically determined disorder. Besides this, the most common reason for neonatal hypoglycaemia is the inmature liver storage of glucose seen in preterms or children born intrauterine growth retarded. The genetic determination of hypoglycaemia is gene- and allele- heterogeneous, and thus complex to diagnose. Nevertheless its contribution to brain damage and intellectual disability in children provides a strong rationale for comprehensive and rapid testing. Hypoglycaemia may contribute directly to the phenotype of various genetic syndromes but because of their rarity, it has been not always included in differential diagnosis and its frequency has been underestimated. In clinical practice but also with the growing attention to improved neonatal helathcare and to neonatal genetic screening programmes, the detailed classification of genotype to phenotype is of great importance. This review provides a catalogue of syndromic forms of neonatal hypoglycaemia.

Transcription alterations of KCNQ1 associated with imprinted methylation defects in the Beckwith-Wiedemann locus.

PURPOSE: Beckwith-Wiedemann syndrome (BWS) is a developmental disorder caused by dysregulation of the imprinted gene cluster of chromosome 11p15.5 and often associated with loss of methylation (LOM) of the imprinting center 2 (IC2) located in KCNQ1 intron 10. To unravel the etiological mechanisms underlying these epimutations, we searched for genetic variants associated with IC2 LOM. METHODS: We looked for cases showing the clinical features of both BWS and long QT syndrome (LQTS), which is often associated with KCNQ1 variants. Pathogenic variants were identified by genomic analysis and targeted sequencing. Functional experiments were performed to link these pathogenic variants to the imprinting defect. RESULTS: We found three rare cases in which complete IC2 LOM is associated with maternal transmission of KCNQ1 variants, two of which were demonstrated to affect KCNQ1 transcription upstream of IC2. As a consequence of KCNQ1 haploinsufficiency, these variants also cause LQTS on both maternal and paternal transmission. CONCLUSION: These results are consistent with the hypothesis that, similar to what has been demonstrated in mouse, lack of transcription across IC2 results in failure of methylation establishment in the female germline and BWS later in development, and also suggest a new link between LQTS and BWS that is important for genetic counseling.

Next generation sequencing and imprinting disorders: Current applications and future perspectives: Lessons from Silver-Russell syndrome.

Imprinting Disorders are a group of rare diseases with overlapping phenotypes which are associated with similar molecular changes and affect imprinted chromosomal regions. Clinical features mainly occur prenatally or in childhood, but have a severe lifelong impact on health. Due to their clinical and molecular heterogeneity, the diagnosis of imprinting disorders is often challenging and requires testing of a broad spectrum of genomic variants and aberrant methylation of imprinted loci (epimutations). A significant number of patients suspicious for imprinting disorders remain without a molecular confirmation, and in these cases differential diagnoses have to be considered. In fact, in patients with clinical features suggestive for imprinting disorders, the precise identification of the molecular cause is relevant for both clinical management as well as for genetic counselling. Thus, a comprehensive testing approach has to be applied. Next generation sequencing (NGS) based studies show that this technique is a valuable tool to improve the diagnostic efficiency particularly in entities with broad differential diagnoses. Furthermore, the development of diverse NGS approaches allows new insights in the function of imprinted regions, their structures, interactions and regulation. Based on a large cohort of patients referred for routine Silver Russel syndrome testing, the appropriateness and limitations of first trial tests in imprinting disorders are demonstrated in this report, but the chances of genomic NGS approaches for diagnostics and research are elucidated as well. Finally, the significance of the precise molecular diagnosis for the personalized management of the patient, and genetic counselling of the family will be discussed.

Targeted Next Generation Sequencing Approach in Patients Referred for Silver-Russell Syndrome Testing Increases the Mutation Detection Rate and Provides Decisive Information for Clinical Management.

OBJECTIVE: To investigate the contribution of differential diagnoses to the mutation spectrum of patients referred for Silver-Russell syndrome (SRS) testing. STUDY DESIGN: Forty-seven patients referred for molecular testing for SRS were examined after exclusion of one of the SRS-associated alterations. After clinical classification, a targeted next generation sequencing approach comprising 25 genes associated with other diagnoses or postulated as SRS candidate genes was performed. RESULTS: By applying the Netchine-Harbinson clinical scoring system, indication for molecular testing for SRS was confirmed in 15 out of 47 patients. In 4 out of these 15 patients, disease-causing variants were found in genes associated with other diagnoses. These patients carried mutations associated with Bloom syndrome, Mulibrey nanism, KBG syndrome, or IGF1R-associated short stature. We could not detect any pathogenic mutation in patients with a negative clinical score. CONCLUSIONS: Some of the differential diagnoses detected in the cohort presented here have a major impact on clinical management. Therefore, we emphasize that the molecular defects associated with these clinical pictures should be excluded before the clinical diagnosis "SRS" is made. Finally, we could show that a broad molecular approach including the differential diagnoses of SRS increases the detection rate.

Epigenetic Influences During the Periconception Period and Assisted Reproduction.

The periconception period starts 6 months before conception and lasts until the tenth week of gestation. In this chapter, we will focus on epigenetic modifications to DNA and gene expression within this period and during assisted reproduction. There are two critical times during the periconception window when significant epigenetic 'reprogramming' occur: one during gametogenesis and another during the pre-implantation embryonic stage. Furthermore, assisted conception treatments, laboratory protocols and culture media can affect the embryo development and birth weights in laboratory animals. There is, however, an ongoing debate as to whether epigenetic changes in humans, causing embryo mal-development, placenta dysfunction and birth defects, result from assisted reproductive technologies or are consequences of pre-existing medical and/or genetic conditions in the parents. The periconception period starts from ovarian folliculogenesis, through resumption of oogenesis, fertilisation, peri-implantation embryo development, embryogenesis until the end of organogenesis. In men, it is the period from spermatogenesis to epididymal sperm storage and fertilisation. Gametes and developing embryos are sensitive to environmental factors during this period, and epigenetic modifications can occur in response to adverse lifestyles and environmental factors. We now know that lifestyle factors such as advanced parentage age, obesity or undernutrition, smoking, excessive alcohol and caffeine intake and recreational drugs used during gamete production and embryogenesis could induce epigenetic alterations, which could impact adversely on pregnancy outcomes and health of the offspring. Furthermore, these can also result in a permanent and irreversible effect in a dose-dependent manner, which can be passed on to the future generations.

Clinical and molecular analyses of Beckwith-Wiedemann syndrome: Comparison between spontaneous conception and assisted reproduction techniques.

Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome characterized by an excessive prenatal and postnatal growth, macrosomia, macroglossia, and hemihyperplasia. The molecular basis of this syndrome is complex and heterogeneous, involving genes located at 11p15.5. BWS is correlated with assisted reproductive techniques. BWS in individuals born following assisted reproductive techniques has been found to occur four to nine times higher compared to children with to BWS born after spontaneous conception. Here, we report a series of 187 patients with to BWS born either after assisted reproductive techniques or conceived naturally. Eighty-eight percent of BWS patients born via assisted reproductive techniques had hypomethylation of KCNQ1OT1:TSS-DMR in comparison with 49% for patients with BWS conceived naturally. None of the patients with BWS born via assisted reproductive techniques had hypermethylation of H19/IGF2:IG-DMR, neither CDKN1 C mutations nor patUPD11. We did not find differences in the frequency of multi-locus imprinting disturbances between groups. Patients with BWS born via assisted reproductive techniques had an increased frequency of advanced bone age, congenital heart disease, and decreased frequency of earlobe anomalies but these differences may be explained by the different molecular background compared to those with BWS and spontaneous fertilization. We conclude there is a correlation of the molecular etiology of BWS with the type of conception. © 2016 Wiley Periodicals, Inc.

PLAGL1 epimutation and bladder exstrophy: Coincidence or concurrent etiology?

BACKGROUND: The bladder exstrophy-epispadias complex (BEEC) is characterized by a spectrum of genitourinary malformations. Both classical bladder exstrophy and the most severe phenotype, exstrophy of the cloaca, display omphaloceles, a cardinal anomaly of some disorders caused by altered imprinting. Therefore, we hypothesized that BEEC in some patients could occur on the basis of an undiagnosed imprinting disorder. Such altered imprinting is associated with changes in the parent-of-origin-specific DNA methylation. METHODS: We analyzed the DNA methylation of 54 imprinted loci in 23 selected patients with different BEEC subtypes (epispadias n = 1, classical bladder exstrophy n = 10, exstrophy of the cloaca n = 12) using the Infinium HumanMethylation450 BeadChip. A total of 471,722 not imprinted autosomal CpG loci and 891 imprinted CpG loci were investigated. Findings were corroborated by methylation-specific-multiplex ligation-dependent probe amplification (MS-MLPA) and microsatellite analysis. RESULTS: No significant differences in the DNA methylation of the not imprinted and imprinted CpG were observed depending on subtype of BEEC. Nevertheless, in 1 of the 23 patients who displayed a classical bladder exstrophy, we detected hypomethylation of the imprinted PLAGL1 locus in chromosome 6q24. We verified this hypomethylation by MS-MLPA and showed further the methylation loss to be caused most likely by a mosaic epimutation. CONCLUSION: Considering that it is highly unlikely to detect a PLAGL1 epimutation among 23 individuals given the low incidence of this alteration in the population, our observations further support a link between BEEC and imprinting disorders. Birth Defects Research (Part A) 106:724-728, 2016. © 2016 Wiley Periodicals, Inc.

Exhaustive methylation analysis revealed uneven profiles of methylation at IGF2/ICR1/H19 11p15 loci in Russell Silver syndrome.

BACKGROUND: The structural organisation of the human IGF2/ICR1/H19 11p15 domain is very complex, and the mechanisms underlying its regulation are poorly understood. The Imprinted Center Region 1 (ICR1) contains seven binding sites for the zinc-finger protein CTCF (CBS: CTCF Binding Sites); three additional differentially methylated regions (DMR) are located at the H19 promoter (H19DMR) and two in the IGF2 gene (DMR0 and DMR2), respectively. Loss of imprinting at the IGF2/ICR1/H19 domain results in two growth disorders with opposite phenotypes: Beckwith-Wiedemann syndrome and Russell Silver syndrome (RSS). Despite the IGF2/ICR1/H19 locus being widely studied, the extent of hypomethylation across the domain remains not yet addressed in patients with RSS. METHODS: We assessed a detailed investigation of the methylation status of the 11p15 ICR1 CBS1-7, IGF2DMR0 and H19DMR (H19 promoter) in a population of controls (n=50) and RSS carrying (n=104) or not (n=65) carrying a hypomethylation at the 11p15 ICR1 region. RESULTS: The methylation indexes (MI) were balanced at all regions in the control population and patients with RSS without any as yet identified molecular anomaly. Interestingly, patients with RSS with ICR1 hypomethylation showed uneven profiles of methylation among the CBSs and DMRs. Furthermore, normal MIs at CBS1 and CBS7 were identified in 9% of patients. CONCLUSIONS: The hypomethylation does not spread equally throughout the IGF2/ICR1/H19 locus, and some loci could have normal MI, which may lead to underdiagnosis of patients with RSS with ICR1 hypomethylation. The uneven pattern of methylation suggests that some CBSs may play different roles in the tridimensional chromosomal looping regulation of this locus.

Congenital imprinting disorders: Application of multilocus and high throughput methods to decipher new pathomechanisms and improve their management.

Imprinting disorders (IDs) are a group of congenital diseases affecting growth, development and metabolism. They are caused by changes in the allele-specific regulation ("epigenetic mutation") or in the genomic sequence ("genetic mutation") of imprinted genes. Currently molecular tests in ID patients are generally restricted to single loci classically associated with the disease, but this approach limits diagnostic yield, because of the molecular and clinical heterogeneity between IDs. From the technical point of view, these limitations are aggravated by the lack of standardization in testing methodology, in the DNA sequences tested, and in clinical inclusion criteria prompting testing. However, an increasing number of new studies show that these problems can be addressed by the use of new tests targeting multiple loci and/or a total exome and genome analysis. The rapid development of efficient and high-throughput molecular techniques and their applications in research and diagnostics in the last decade have led to an impressive increase of knowledge on IDs and their basic pathomechanisms. In combination with the improvement of data recording and documentation, the diagnostic strategies are increasingly based on standardized protocols, and thereby provide the backbone for directed counseling, more personalized management, and new therapeutic approaches.

Complex tissue-specific epigenotypes in Russell-Silver Syndrome associated with 11p15 ICR1 hypomethylation.

Russell-Silver Syndrome (RSS) is a prenatal and postnatal growth retardation syndrome caused mainly by 11p15 ICR1 hypomethylation. Clinical presentation is heterogeneous in RSS patients with 11p15 ICR1 hypomethylation. We previously identified a subset of RSS patients with 11p15 ICR1 and multilocus hypomethylation. Here, we examine the relationships between IGF2 expression, 11p15 ICR1 methylation, and multilocus imprinting defects in various cell types from 39 RSS patients with 11p15 ICR1 hypomethylation in leukocyte DNA. 11p15 ICR1 hypomethylation was more pronounced in leukocytes than in buccal mucosa cells. Skin fibroblast IGF2 expression was correlated with the degree of ICR1 hypomethylation. Different tissue-specific multilocus methylation defects coexisted in 38% of cases, with some loci hypomethylated and others hypermethylated within the same cell type in some cases. Our new results suggest that tissue-specific epigenotypes may lead to clinical heterogeneity in RSS.

Health outcomes of children born after IVF/ICSI: a review of current expert opinion and literature.

The Sixth Evian Annual Reproduction (EVAR) Workshop Group Meeting was held to evaluate the impact of IVF/intracytoplasmic sperm injection on the health of assisted-conception children. Epidemiologists, reproductive endocrinologists, embryologists and geneticists presented data from published literature and ongoing research on the incidence of genetic and epigenetic abnormalities and congenital malformations in assisted-conception versus naturally conceived children to reach a consensus on the reasons for potential differences in outcomes between these two groups. IVF-conceived children have lower birthweights and higher peripheral fat, blood pressure and fasting glucose concentrations than controls. Growth, development and cognitive function in assisted-conception children are similar to controls. The absolute risk of imprinting disorders after assisted reproduction is less than 1%. A direct link between assisted reproduction and health-related outcomes in assisted-conception children could not be established. Women undergoing assisted reproduction are often older, increasing the chances of obtaining abnormal gametes that may cause deviations in outcomes between assisted-conception and naturally conceived children. However, after taking into account these factors, it is not clear to what extent poorer outcomes are due to the assisted reproduction procedures themselves. Large-scale, multicentre, prospective epidemiological studies are needed to investigate this further and to confirm long-term health consequences in assisted-conception children. Assisted reproduction treatment is a general term used to describe methods of achieving pregnancy by artificial means and includes IVF and sperm implantation. The effect of assisted reproduction treatment on the health of children born using these artificial methods is not fully understood. In April 2011, fertility research experts met to give presentations based on research in this area and to look carefully at the evidence for the effects of assisted reproduction treatment on children's health. The purpose of this review was to reach an agreement on whether there are differences in the health of assisted-conception children with naturally conceived children. The researchers discovered no increased risk in birth defects in assisted-conception children compared with naturally conceived children. They found that IVF-conceived children have lower birth weights and higher fat under the skin, higher blood pressure and higher fasting glucose concentrations than naturally conceived children; however, growth, development and cognitive function are similar between groups. A very low risk of disorders of genetic control was observed in assisted-conception children. Overall, there did not appear to be a direct link between assisted reproduction treatment and children's health. The researchers concluded that the cause of some differences in the health of children conceived using assisted reproduction treatment may be due to the age of the woman receiving treatment. Large-scale, research studies are needed to study the long-term health of children conceived using assisted reproduction treatment.

Pregnancy outcomes after assisted human reproduction.

OBJECTIVE: To review the effect of assisted human reproduction (AHR) on perinatal outcomes, to identify areas requiring further research with regard to birth outcomes and AHR, and to provide guidelines to optimize obstetrical management and counselling of prospective Canadian parents. OUTCOMES: This document compares perinatal outcomes of different types of AHR pregnancies with each other and with those of spontaneously conceived pregnancies. Clinicians will be better informed about the adverse outcomes that have been documented in association with AHR, including obstetrical complications, adverse perinatal outcomes, multiple gestations, structural congenital abnormalities, chromosomal abnormalities, and imprinting disorders. EVIDENCE: Published literature was retrieved through searches of MEDLINE and the Cochrane Library from January 2005 to December 2012 using appropriate controlled vocabulary and key words (assisted reproduction, assisted reproductive technology, ovulation induction, intracytoplasmic sperm injection, embryo transfer, and in vitro fertilization). Results were not restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies; studies of all designs published in English from January 2005 to December 2012 were reviewed, and additional publications were identified from the bibliographies of these articles. Searches were updated on a regular basis and incorporated in the guideline to August 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. VALUES: The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Summary Statements 1. There is increasing evidence that infertility or subfertility is an independent risk factor for obstetrical complications and adverse perinatal outcomes, even without the addition of assisted human reproduction. (II-2) 2. The relative risk for an imprinting phenotype such as Silver-Russell syndrome, Beckwith-Wiedemann syndrome, or Angelman syndrome is increased in the assisted reproduction population, but the actual risk for one of these phenotypes to occur in an assisted pregnancy is estimated to be low, at less than 1 in 5000. The exact biological etiology for this increased imprinting risk is likely heterogeneous and requires more research. (II-2) Recommendations 1. All men with severe oligozoospermia or azoospermia (sperm count < 5 million/hpf) should be offered genetic/clinical counselling, karyotype assessment for chromosomal abnormalities, and Y-chromosome microdeletion testing prior to in vitro fertilization with intracytoplasmic sperm injection. (II-2A) 2. All men with unexplained obstructive azoospermia should be offered genetic/clinical counselling and genetic testing for cystic fibrosis prior to in vitro fertilization with intracytoplasmic sperm injection. (II-2A) 3. Multiple pregnancy is the most powerful predictive factor for adverse maternal, obstetrical, and perinatal outcomes. Couples should be thoroughly counselled about the significant risks of multiple pregnancies associated with all assisted human reproductive treatments. (II-2A) 4. The benefits and cumulative pregnancy rates of elective single embryo transfer support a policy of using this protocol in couples with good prognosis for success, and elective single embryo transfer should be strongly encouraged in this population. (II-2A) 5. To reduce the incidence of multiple pregnancy, health care policies that support public funding for assisted human reproduction, with regulations promoting best practice regarding elective single embryo transfer, should be strongly encouraged. (II-2A) 6. Among singleton pregnancies, assisted reproductive technology is associated with increased risks of preterm birth and low birth weight infants, and ovulation induction is associated with an increased risk of low birth weight infants. Until sufficient research has clarified the independent roles of infertility and treatment for infertility, couples should be counselled about the risks associated with treatment. (II-2B) There is a role for closer obstetric surveillance of women who conceive with assisted human reproduction. (III-L) 7. There is growing evidence that pregnancy outcomes are better for cryopreserved embryos fertilized in vitro than for fresh embryo transfers. This finding supports a policy of elective single embryo transfer for women with a good prognosis (with subsequent use of cryopreserved embryos as necessary), and may reassure women who are considering in vitro fertilization. (II-2A) 8. Women and couples considering assisted human reproduction and concerned about perinatal outcomes in singleton pregnancies should be advised that (1) intracytoplasmic sperm injection does not appear to confer increased adverse perinatal or maternal risk over standard in vitro fertilization, and (2) the use of donor oocytes increases successful pregnancy rates in selected women, but even when accounting for maternal age, can increase the risks of low birth weight and preeclampsia. (II-2B) 9. Any assisted reproductive technology procedure should be prefaced by a discussion of fetal outcomes and the slight increase in the risk of congenital structural abnormalities, with emphasis on known confounding factors such as infertility and body mass index. (II-2B) 10. In pregnancies achieved by artificial reproductive technology, routine anatomic ultrasound for congenital structural abnormalities is recommended between 18 and 22 weeks. (II-2A) 11. Pregnancies conceived by intracytoplasmic sperm injection may be at increased risk of chromosomal aberrations, including sex chromosome abnormalities. Diagnostic testing should be offered after appropriate counselling. (II-2A) 12. The possible increased risk for late onset cancer due to gene dysregulation for tumour suppression requires more long-term follow-up before the true risk can be determined. (III-A) 13. The clinical application of preimplantation genetic testing in fertile couples must balance the benefits of avoiding disease transmission with the medical risks and financial burden of in vitro fertilization. (III-B) 14. Preimplantation screening for aneuploidy is associated with inconsistent findings for improving pregnancy outcomes. Any discussion of preimplantation genetic screening with patients should clarify that there is no adequate information on the long-term effect of embryo single cell biopsy. (I-C).

Objectif : Analyser l'effet du recours à la procréation assistée (PA) sur les issues périnatales, identifier les aspects propres aux issues de naissance et à la PA qui nécessitent des recherches approfondies, et fournir des lignes directrices permettant l'optimisation de la prise en charge obstétricale et du counseling des parents potentiels canadiens. Issues : Le présent document compare les issues périnatales constatées dans le cadre de différents types de grossesse attribuable à la PA les unes aux autres, ainsi qu'à celles qui sont constatées dans le cadre des grossesses conçues de façon spontanée. Les cliniciens seront mieux renseignés au sujet des issues indésirables associées à la PA qui ont été documentées, y compris les complications obstétricales, les issues périnatales indésirables, les gestations multiples, les anomalies congénitales structurelles, les anomalies chromosomiques et les troubles de l'empreinte génomique. Résultats : La littérature publiée a été récupérée par l'intermédiaire de recherches menées dans MEDLINE et The Cochrane Library entre janvier 2005 et décembre 2012 au moyen d'un vocabulaire contrôlé et de mots clés appropriés (« assisted reproduction ¼, « assisted reproductive technology ¼, « ovulation induction ¼, « intracytoplasmic sperm injection ¼, « embryo transfer ¼ et « in vitro fertilization ¼). Les résultats n'ont pas été restreints aux analyses systématiques, aux essais comparatifs randomisés / essais cliniques comparatifs et aux études observationnelles; les études (tous devis confondus) publiées en anglais entre janvier 2005 et décembre 2012 ont été analysées, et des publications additionnelles ont été identifiées à partir des bibliographies de ces études. Les recherches ont été mises à jour de façon régulière et intégrées à la directive clinique jusqu'en août 2013. La littérature grise (non publiée) a été identifiée par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales. Valeurs : La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau). Déclarations sommaires 1. De plus en plus de données indiquent que l'infertilité ou l'hypofertilité constitue un facteur de risque indépendant en ce qui concerne les complications obstétricales et les issues périnatales indésirables, même sans l'ajout de la procréation assistée. (II-2) 2. Bien que le risque relatif de voir apparaître un phénotype d'empreinte génomique (comme le syndrome de Silver-Russell, le syndrome de Beckwith-Wiedemann ou le syndrome d'Angelman) soit accru au sein de la population issue de la procréation assistée, on estime que le risque réel de voir apparaître un de ces phénotypes dans le cadre d'une grossesse attribuable à la procréation assistée est faible (inférieur à 1 sur 5 000). L'étiologie biologique exacte de cette hausse du risque lié à l'empreinte génomique est probablement hétérogène et nécessite la tenue d'autres recherches. (II-2) Recommandations 1. Tous les hommes qui présentent une oligozoospermie ou une azoospermie graves (numération de spermatozoïdes < 5 millions/hpf) devraient se voir offrir des services de counseling génétique / clinique, une évaluation du caryotype visant les anomalies chromosomiques et un dépistage des microdélétions du chromosome Y avant la tenue d'une fécondation in vitro-injection intracytoplasmique d'un spermatozoïde. (II-2A) 2. Tous les hommes qui présentent une azoospermie obstructive inexpliquée devraient se voir offrir des services de counseling génétique / clinique et un dépistage génétique visant la fibrose kystique avant la tenue d'une fécondation in vitro-injection intracytoplasmique d'un spermatozoïde. (II-2) 3. La grossesse multiple constitue le facteur prédictif le plus puissant en ce qui concerne les issues indésirables maternelles, obstétricales et périnatales. Les couples devraient bénéficier de services de counseling exhaustifs au sujet des risques importants que posent les grossesses multiples associées aux traitements de procréation assistée, tous types confondus. (II-2A) 4. Les avantages et les taux cumulatifs de grossesse associés au transfert sélectif d'un seul embryon soutiennent la mise en œuvre d'une politique en instaurant l'utilisation chez les couples qui présentent un bon pronostic de réussite; le recours au transfert sélectif d'un seul embryon devrait être fortement encouragé chez cette population. (II-2) 5. Pour réduire l'incidence de la grossesse multiple, la mise en œuvre de politiques de santé soutenant le financement public de la procréation assistée (le tout s'accompagnant de règlements faisant la promotion de l'adoption de pratiques optimales à l'égard du transfert sélectif d'un seul embryon) devrait être fortement encouragée. (II-2A) 6. Dans le cas des grossesses monofœtales, les techniques de procréation assistée sont associées à un risque accru de connaître un accouchement préterme et d'obtenir un enfant présentant un faible poids de naissance, et le déclenchement de l'ovulation est associé à un risque accru d'obtenir un enfant présentant un faible poids de naissance. Jusqu'à ce qu'un nombre suffisant de recherches aient été menées pour clarifier les rôles indépendants de l'infertilité et des traitements contre l'infertilité, les couples devraient bénéficier de services de counseling au sujet des risques associés au traitement. (II-2B) La mise en œuvre d'une surveillance obstétricale plus étroite a un rôle à jouer dans la prise en charge des femmes qui ont recours à la procréation assistée. (III-L) 7. De plus en plus de données indiquent que les issues de grossesse sont meilleures lorsque l'on a recours au transfert d'embryons fécondés in vitro, puis cryoconservés, plutôt qu'au transfert d'embryons frais. Cette constatation soutient la mise en œuvre d'une politique instaurant l'utilisation du transfert sélectif d'un seul embryon chez les couples qui présentent un bon pronostic de réussite (suivie de l'utilisation d'embryons cryoconservés, au besoin) et pourrait rassurer les femmes qui envisagent d'avoir recours à la fécondation in vitro. (II-2A) 8. Les femmes et les couples qui envisagent d'avoir recours à la procréation assistée, et qui entretiennent des préoccupations au sujet des issues périnatales associées aux grossesses monofœtales devraient être avisés que (1) l'injection intracytoplasmique d'un spermatozoïde ne semble pas donner lieu à une hausse du risque maternel ou du risque d'obtenir des issues périnatales indésirables, par comparaison avec la fécondation in vitro standard, et que (2) le recours à des ovocytes issus de donatrices entraîne la hausse des taux de grossesse réussie chez certaines femmes, mais qu'il peut également accroître le risque de faible poids de naissance et de prééclampsie, même en tenant compte de l'âge maternel. (II-2B) 9. Le recours à toute intervention faisant appel aux techniques de procréation assistée devrait être précédé d'une discussion sur les issues fœtales et la légère hausse du risque d'anomalies congénitales structurelles, en s'assurant de mettre l'accent sur les facteurs de confusion connus (tels que l'infertilité et l'indice de masse corporelle). (II-2B) 10. Dans le cas des grossesses attribuables aux techniques de procréation assistée, la tenue systématique d'une échographie anatomique visant les anomalies congénitales structurelles est recommandée entre 18 et 22 semaines. (II-2A) 11. Les grossesses attribuables à l'injection intracytoplasmique d'un spermatozoïde pourraient être exposées à un risque accru d'aberrations chromosomiques, y compris des anomalies affectant les chromosomes sexuels. Des tests diagnostiques devraient être offerts à la suite de l'offre de services de counseling appropriés. (II-2A) 12. La hausse possible du risque de cancer d'apparition tardive attribuable à la dysrégulation génique de la suppression tumorale nécessite la mise en œuvre d'un suivi à plus long terme, et ce, jusqu'à ce que le risque réel puisse être déterminé. (III-A) 13. La mise en œuvre clinique du dépistage génétique préimplantatoire chez les couples fertiles doit mettre en balance les avantages du fait d'éviter la transmission de pathologies et les risques médicaux (et le fardeau financier) de la fécondation in vitro. (III-B) 14. Le dépistage préimplantatoire de l'aneuploïdie est associé à des constatations hétérogènes pour ce qui est de l'amélioration des issues de grossesse. Toute discussion avec les patientes au sujet du dépistage génétique préimplantatoire devrait mettre au clair que nous ne disposons pas de renseignements adéquats quant aux effets à long terme de la biopsie unicellulaire de l'embryon. (I-C).