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Abstract Imprinted genes exhibit a parent-of-origin specific pattern of expression. Such genes have been shown to be targets of molecular defects in particular genetic syndromes such as Beckwith-Wiedemann and Angelman syndromes. Recent reports have raised concern about the possibility that assisted reproduction techniques, such as in vitro fertilization or intracytoplasmic sperm injection, might cause genomic imprinting disorders. The number of reported cases of those disorders is still too small to draw firm conclusions and the safety of these widely used assisted reproduction techniques needs to be further evaluated.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease with complete penetrance, most commonly known to affect the skin and eyes. Although lung involvement in the form of cysts and bullae occurs in up to 20% of adults, the seemingly intuitive association of NF1 and spontaneous pneumothorax is not widely recognised among clinicians. Here, we report the second case of recurring spontaneous pneumothorax in the context of NF1 with a confirmed molecular diagnosis. In both cases, the NF1 variants featured a premature stop codon in the C-terminal protein domain. Interestingly, our patient had mild skin symptoms, suggesting that spontaneous pneumothorax may not be correlated with cutaneous disease severity. More genotype–phenotype correlation studies are needed for NF1 in general and for its link to spontaneous pneumothorax in particular. [ABSTRACT FROM AUTHOR]

Introduction: Interpersonal violent (IPV) experiences when they begin in childhood and continue in various forms during adulthood often lead to chronic post-traumatic stress disorder (PTSD) that is associated in multiple studies with hypocortisolism and lower percentage of methylation of the promoter region of the gene coding for the glucocorticoid receptor (NR3C1). This prospective, longitudinal study examined the relationship of NR3C1 methylation among mothers with IPV-related PTSD and their toddlers and then looked at the relationship of maternal NR3C1 methylation and child psychopathology at school age. Methods: Forty-eight mothers were evaluated for life-events history and post-traumatic stress disorder via structured clinical interview when their children were ages 12-42 months (mean age 26.7 months, SD 8.8). Their children's psychopathology in terms of internalizing symptoms and externalizing behaviors was evaluated using the Child Behavior Checklist at ages 5-9 years (mean age 7 years, SD 1.1). Percentage of methylation for the NR3C1 gene promoter region was assessed from DNA extracted from maternal and child saliva using bisulfite pyrosequencing. Data analysis involved parametric and non-parametric correlations and multiple linear and logistic regression modeling. Results: Logistic regression models using child NR3C1 methylation as the dependent variable and maternal NR3C1 methylation and PTSD group status as predictors, as well as the interaction indicated that all three of these significantly predicted child NR3C1 methylation. These findings remained significant when controlling for child age, sex and maternal child abuse history. Overall, maternal NR3C1 methylation when children were toddlers was negatively and significantly associated with child externalizing behavior severity at school age. Discussion: We found that correlations betweenmothers and their children of NR3C1methylation levels overall and at all individual CpG sites of interest were significant only in the IPV-PTSD group. The latter findings support that NR3C1 methylation in mothers positively and statistically significantly correlates with NR3C1 methylation in their children only in presence of IPV-PTSD in the mothers. Thismaternal epigenetic signature with respect to this glucocorticoid receptor is significantly associated with child behavior thatmay well pose a risk for intergenerational transmission of violence and related psychopathology. [ABSTRACT FROM AUTHOR]

Bi‐allelic loss‐of‐function variants of OTOA are a well‐known cause of moderate‐to‐severe hearing loss. Whereas non‐allelic homologous recombination‐mediated deletions of the gene are well known, gene conversions to pseudogene OTOAP1 have been reported in the literature but never fully described nor their pathogenicity assessed. Here, we report two unrelated patients with moderate hearing‐loss, who were compound heterozygotes for a converted allele and a deletion of OTOA. The conversions were initially detected through sequencing depths anomalies at the OTOA locus after exome sequencing, then confirmed with long range polymerase chain reactions. Both conversions lead to loss‐of‐function by introducing a premature stop codon in exon 22 (p.Glu787*). Using genomic alignments and long read nanopore sequencing, we found that the two probands carry stretches of converted DNA of widely different lengths (at least 9 kbp and around 900 bp, respectively). [ABSTRACT FROM AUTHOR]

Purpose: The INTERMED instrument, which was developed to measure patient's biopsychosocial (BPS) complexity, represents a powerful diagnostic and therapeutic tool. Epigenetic changes are the interface between signals from the environment and genetic modifications, affecting gene expression, in particular, by DNA methylation of CpG dinucleotides in promotor regions of the corresponding genes. The brain-derived neurotrophic factor (BDNF) gene plays a crucial role in the central sensitization (CS) of pain. In this study, we hypothesized that chronic pain modifies the methylation levels of the BDNF gene in a manner that is interconnected with the BPS status. Patients and Methods: Fifty-eight chronic musculoskeletal pain patients (CMSP) were enrolled in the study. DNA was extracted from blood samples, the methylation levels of 13 CpG sites in the BDNF promoter were measured by pyrosequencing, and association studies with various patient parameters and the INTERMED scores were performed. Results: Interestingly, a negative correlation (− 0.40) was found between the total INTERMED scores and the average CpG methylation values of the BDNF gene, but no correlation was observed with the severity of pain, degree of anxiety, depression, or kinesiophobia and catastrophism. Moreover, the association was independent of age, sex and level of comorbidities. Conclusion: This result shows that CMSP, in association with its biopsychosocial context, epigenetically decreases the degree of methylation of the BDNF promoter and should therefore increase the level of BDNF transcription. It also suggests a role of the INTERMED tool to detect a relationship between the BPS complexity and the epigenetic control of a target gene. The possible upregulation of BDNF expression might be, at least in part, the signal for chronic pain-induced central sensitization (CS). This could partly explain why patients with a higher level of complexity feel more pain than those with lower complexity. [ABSTRACT FROM AUTHOR]

Di(2-ethylhexyl)phthalate (DEHP) interferes with sex hormones signaling pathways (SHP). C57BL/6J mice prenatally exposed to 300 mg/kg/day DEHP develop a testicular dysgenesis syndrome (TDS) at adulthood, but similarly-exposed FVB/N mice are not affected. Here we aim to understand the reasons behind this drastic difference that should depend on the genome of the strain. In both backgrounds, pregnant female mice received per os either DEHP or corn oil vehicle and the male filiations were examined. Computer-assisted sperm analysis showed a DEHP-induced decreased sperm count and velocities in C57BL/6J. Sperm RNA sequencing experiments resulted in the identification of the 62 most differentially expressed RNAs. These RNAs, mainly regulated by hormones, produced strain-specific transcriptional responses to prenatal exposure to DEHP; a pool of RNAs was increased in FVB, another pool of RNAs was decreased in C57BL/6J. In FVB/N, analysis of non-synonymous single nucleotide polymorphisms (SNP) impacting SHP identified rs387782768 and rs29315913 respectively associated with absence of the Forkhead Box A3 (Foxa3) RNA and increased expression of estrogen receptor 1 variant 4 (NM_001302533) RNA. Analysis of the role of SNPs modifying SHP binding sites in function of strain-specific responses to DEHP revealed a DEHP-resistance allele in FVB/N containing an additional FOXA1-3 binding site at rs30973633 and four DEHP-induced beta-defensins (Defb42, Defb30, Defb47 and Defb48). A DEHP-susceptibility allele in C57BL/6J contained five SNPs (rs28279710, rs32977910, rs46648903, rs46677594 and rs48287999) affecting SHP and six genes (Svs2, Svs3b, Svs4, Svs3a, Svs6 and Svs5) epigenetically silenced by DEHP. Finally, targeted experiments confirmed increased methylation in the Svs3ab promoter with decreased SEMG2 persisting across generations, providing a molecular explanation for the transgenerational sperm velocity decrease found in C57BL/6J after DEHP exposure. We conclude that the existence of SNP-dependent mechanisms in FVB/N inbred mice may confer resistance to transgenerational endocrine disruption. [ABSTRACT FROM AUTHOR]

Background: Corticosteroids are associated with reduced bone mineral density (BMD), as well as water and salt retention, leading to hypertension. They are substrates for P-glycoprotein, a protein coded by the highly polymorphic ABCB1 gene. We hypothesized that one ABCB1 polymorphism, rs1045642, is associated with blood pressure and BMD parameters at 1-year post kidney transplantation (KT). Methods: Rs1045642 was genotyped using pyrosequencing in 40 KT recipients. Both dominant (CC vs. CT + TT) and codominant (CC vs. CT vs. TT) genetic models (analysis of variance from linear regressions) were adjusted for confounding variables (age, sex, type of nephropathy, glomerular filtration rate, and corticosteroid use at 1 year). Results: Rs1045642 genotypes were significantly associated with systolic (SBP) and diastolic (DBP) blood pressure 1-year post-transplantation, independent of the genetic model used (adjusted codominant model: SBP p-value = 0.015, DBP p-value = 0.038; adjusted dominant model: SBP p-value = 0.003, DBP p-value = 0.011). A non-statistically significant trend was observed for an association between rs1045642 and BMD change at 1-year post-KT. Conclusions: Rs1045642 is significantly associated with higher BP 1 year after KT. Further investigations are necessary to confirm the role of rs1045642 in corticosteroid-related adverse effects. [ABSTRACT FROM AUTHOR]

The endocrine disruptor bis(2-ethylhexyl) phthalate (DEHP) has been shown to exert adverse effects on the male animal reproductive system. However, its mode of action is unclear and a systematic analysis of its molecular targets is needed. In the present study, we investigated the effects of prenatal exposure to 300 mg/kg/day DEHP during a critical period for gonads differentiation to testes on male mice offspring reproductive parameters, including the genome-wide RNA expression and associated promoter methylation status in the sperm of the first filial generation. It was observed that adult male offspring displayed symptoms similar to the human testicular dysgenesis syndrome. A combination of sperm transcriptome and methylome data analysis allowed to detect a long-lasting DEHP-induced and robust promoter methylation-associated silencing of almost the entire cluster of the seminal vesicle secretory proteins and antigen genes, which are known to play a fundamental role in sperm physiology. It also resulted in the detection of a DEHP-induced promoter demethylation associated with an up-regulation of three genes apparently not relevant for sperm physiology and partially related to the immune system. As previously reported, DEHP induced an increase in mir-615 microRNA expression and a genome-wide decrease in microRNA promoter methylation. A functional analysis revealed DEHP-induced enrichments in down-regulated gene transcripts coding for peroxisome proliferator-activated receptors and tumor necrosis factor signaling pathways, and in up-regulated gene transcripts coding for calcium binding and numerous myosin proteins. All these enriched pathways and networks have been described to be associated in some way with the reproductive system. This study identifies a large new array of genes dysregulated by DEHP that may play a role in the complex system controlling the development of the male reproductive system. [ABSTRACT FROM AUTHOR]

Background: Serotonin 3A receptor (5-HT3A R) is associated at the genetic and epigenetic levels with a variety of psychiatric disorders and interacts with early-life stress such as childhood maltreatment. We studied the impact of childhood maltreatment on the methylation status of the 5-HT3A R and its association with clinical severity outcomes in relation with a functional genetic polymorphism.Methods: Clinical severity indexes of 346 bipolar, borderline personality, and adult attention deficit hyperactivity disorders patients were tested for association with the DNA methylation status of eight 5-HT3A R gene CpGs. Relationship between the functional variant rs1062613 (C > T) and methylation status on severity of the disorders were also assessed.Results: Childhood maltreatment was associated with higher severity of the disease (higher number of mood episodes, history of suicide attempts, hospitalization, and younger age at onset) across disorders and within each individual disorder. This effect was mediated by two 5-HT3A R CpGs. Compared to T allele carriers, CC carriers had higher methylation status at one CpG located 1 bp upstream of this variant.Conclusions: This study shows that epigenetic modification of the 5-HT3A R is involved in the mechanism underlying the relationship between maltreatment in childhood and the severity of several psychiatric disorders in adulthood. [ABSTRACT FROM AUTHOR]

It is known that increased circulating glucocorticoids in the wake of excessive, chronic, repetitive stress increases anxiety and impairs Brain-Derived Neurotrophic Factor (BDNF) signaling. Recent studies of BDNF gene methylation in relation to maternal care have linked high BDNF methylation levels in the blood of adults to lower quality of received maternal care measured via self-report. Yet the specific mechanisms by which these phenomena occur remain to be established. The present study examines the link between methylation of the BDNF gene promoter region and patterns of neural activity that are associated with maternal response to stressful versus non-stressful child stimuli within a sample that includes mothers with interpersonal violence-related PTSD (IPV-PTSD). 46 mothers underwent fMRI. The contrast of neural activity when watching children—including their own—was then correlated to BDNF methylation. Consistent with the existing literature, the present study found that maternal BDNF methylation was associated with higher levels of maternal anxiety and greater childhood exposure to domestic violence. fMRI results showed a positive correlation of BDNF methylation with maternal brain activity in the anterior cingulate (ACC), and ventromedial prefrontal cortex (vmPFC), regions generally credited with a regulatory function toward brain areas that are generating emotions. Furthermore we found a negative correlation of BDNF methylation with the activity of the right hippocampus. Since our stimuli focus on stressful parenting conditions, these data suggest that the correlation between vmPFC/ACC activity and BDNF methylation may be linked to mothers who are at a disadvantage with respect to emotion regulation when facing stressful parenting situations. Overall, this study provides evidence that epigenetic signatures of stress-related genes can be linked to functional brain regions regulating parenting stress, thus advancing our understanding of mothers at risk for stress-related psychopathology. [ABSTRACT FROM AUTHOR]

Assisted reproductive technologies (ART) induce vascular dysfunction in humans and mice. In mice, ART-induced vascular dysfunction is related to epigenetic alteration of the endothelial nitric oxide synthase (eNOS) gene, resulting in decreased vascular eNOS expression and nitrite/nitrate synthesis. Melatonin is involved in epigenetic regulation, and its administration to sterile women improves the success rate of ART. We hypothesized that addition of melatonin to culture media may prevent ART-induced epigenetic and cardiovascular alterations in mice. We, therefore, assessed mesenteric-artery responses to acetylcholine and arterial blood pressure, together with DNA methylation of the eNOS gene promoter in vascular tissue and nitric oxide plasma concentration in 12-wk-old ART mice generated with and without addition of melatonin to culture media and in control mice. As expected, acetylcholine-induced mesenteric-artery dilation was impaired (P=0.008 vs. control) and mean arterial blood pressure increased (109.5±3.8 vs. 104.0±4.7 mmHg, P<0.002, ART vs. control) in ART compared with control mice. These alterations were associated with altered DNA methylation of the eNOS gene promoter (P<0.001 vs. control) and decreased plasma nitric oxide concentration (10.1±11.1 vs. 29.5±8.0 -6 M) to culture media prevented eNOS dysmethylation (P=0.005, vs. ART+vehicle), normalized nitric oxide plasma concentration (23.1±14.6 μM, P=0.002 vs. ART + vehicle) and mesentery-artery responsiveness to acetylcholine (P<0.008 vs. ART+vehicle), and prevented arterial hypertension (104.6±3.4 mmHg, P<0.003 vs. ART+vehicle). These findings provide proof of principle that modification of culture media prevents ART-induced vascular dysfunction. We speculate that this approach will also allow preventing ART-induced premature atherosclerosis in humans. [ABSTRACT FROM AUTHOR]

Di-(2-ethylhexyl)phtalate (DEHP) is a plasticizer with endocrine disrupting properties found ubiquitously in the environment and altering reproduction in rodents. Here we investigated the impact of prenatal exposure to DEHP on spermatogenesis and DNA sperm methylation in two distinct, selected, and sequenced mice strains. FVB/N and C57BL/6J mice were orally exposed to 300 mg/kg/day of DEHP from gestation day 9 to 19. Prenatal DEHP exposure significantly decreased spermatogenesis in C57BL/6J (fold-change = 0.6, p-value = 8.7*10-4), but not in FVB/N (fold-change = 1, p-value = 0.9). The number of differentially methylated regions (DMRs) by DEHP-exposure across the entire genome showed increased hyper- and decreased hypo-methylation in C57BL/6J compared to FVB/N. At the promoter level, three important subsets of genes were massively affected. Promoters of vomeronasal and olfactory receptors coding genes globally followed the same trend, more pronounced in the C57BL/6J strain, of being hyper-methylated in DEHP related conditions. In contrast, a large set of micro-RNAs were hypo-methylated, with a trend more pronounced in the FVB/N strain. We additionally analyze both the presence of functional genetic variations within genes that were associated with the detected DMRs and that could be involved in spermatogenesis, and DMRs related with the DEHP exposure that affected both strains in an opposite manner. The major finding in this study indicates that prenatal exposure to DEHP can decrease spermatogenesis in a strain-dependent manner and affects sperm DNA methylation in promoters of large sets of genes putatively involved in both sperm chemotaxis and post-transcriptional regulatory mechanisms. [ABSTRACT FROM AUTHOR]

Prior research has shown that mothers with Interpersonal violence-related posttraumatic stress disorder (IPV-PTSD) report greater difficulty in parenting their toddlers. Relative to their frequent early exposure to violence and maltreatment, these mothers display dysregulation of their hypothalamic pituitary adrenal axis (HPA-axis), characterized by hypocortisolism. Considering methylation of the promoter region of the glucocorticoid receptor gene NR3C1 as a marker for HPA-axis functioning, with less methylation likely being associated with less circulating cortisol, the present study tested the hypothesis that the degree of methylation of this gene would be negatively correlated with maternal IPV-PTSD severity and parenting stress, and positively correlated with medial prefrontal cortical (mPFC) activity in response to video-stimuli of stressful versus non-stressful mother-child interactions. Following a mental health assessment, 45 mothers and their children (ages 12-42 months) participated in a behavioral protocol involving free-play and laboratory stressors such as mother-child separation. Maternal DNA was extracted from saliva. Interactive behavior was rated on the CARE-Index. During subsequent fMRI scanning, mothers were shown films of free-play and separation drawn from this protocol. Maternal PTSD severity and parenting stress were negatively correlated with the mean percentage of methylation of NR3C1. Maternal mPFC activity in response to video-stimuli of mother-child separation versus play correlated positively to NR3C1 methylation, and negatively to maternal IPV-PTSD and parenting stress. Among interactive behavior variables, child cooperativeness in play was positively correlated with NR3C1 methylation. Thus, the present study is the first published report to our knowledge, suggesting convergence of behavioral, epigenetic, and neuroimaging data that form a psychobiological signature of parenting-risk in the context of early life stress and PTSD. [ABSTRACT FROM AUTHOR]

Objectives. Transmission of parental post-traumatic stress disorder (PTSD) to offspring might be explained by transmission of epigenetic processes such as methylation status of the glucocorticoid receptor (GR) gene ( NR3C1). Methods. We investigated PTSD and depression severity, plasma cortisol, GR and mineralocorticoid receptor (MR) levels, and methylation status of NR3C1 and NR3C2 promoter regions in 25 women exposed to the Tutsi genocide during pregnancy and their children, and 25 women from the same ethnicity, pregnant during the same period but not exposed to the genocide, and their children. Results. Transmission of PTSD to the offspring was associated with transmission of biological alterations of the HPA axis. Mothers exposed to the genocide as well as their children had lower cortisol and GR levels and higher MR levels than non-exposed mothers and their children. Moreover, exposed mothers and their children had higher methylation of the NR3C1 exon 1F than non-exposed groups. Finally, exposed mothers showed higher methylation of CpGs located within the NR3C2 coding sequence than non-exposed mothers. Conclusions. PTSD was associated with NR3C1 epigenetic modifications that were similarly found in the mothers and their offspring, modifications that may underlie the possible transmission of biological alterations of the HPA axis. [ABSTRACT FROM AUTHOR]

Imprinting is an epigenetic form of gene regulation that mediates a parent-of-origin-dependent expression of the alleles of a number of genes. Imprinting, which occurs at specific sites within or surrounding the gene, called differentially methylated domains, consists in a methylation of CpGs. The appropriate transmission of genomics imprints is essential for the control of embryonic development and fetal growth. A number of endocrine disruptors (EDs) affect male reproductive tract development and spermatogenesis. It was postulated that the genetic effects of EDs might be induced by alterations in gene imprinting. We tested two EDs: methoxychlor and vinclozolin. Their administration during gestation induced in the offspring a decrease in sperm counts and significant modifications in the methylation pattern of a selection of paternally and maternally expressed canonical imprinted genes. The observation that imprinting was largely untouched in somatic cells suggests that EDs exert their damaging effects via the process of reprogramming that is unique to gamete development. Interestingly, the effects were transgenerational, although disappearing gradually from F1 to F3. A systematic analysis showed a heterogeneity in the CpG sensitivity to EDs. We propose that the deleterious effects of EDs on the male reproductive system are mediated by imprinting defects in the sperm. The reported effects of EDs on human male spermatogenesis might be mediated by analogous imprinting alterations. [ABSTRACT FROM AUTHOR]

We report the case of a 34-year-old female resulting from a father-daughter sexual abuse and presenting a phenotype of mild intellectual disability with minor dysmorphic features. Karyotyping showed a normal 46, XX constitution. Array-based comparative genomic hybridization (array-CGH) revealed a heterozygote 320kb 6p22.3 microdeletion in the proband, encompassing only one known gene, and therefore unlikely to be the cause of the phenotype. However, the role of other genetic factors, such as a recessive condition, could not be ruled out as a putative cause for the phenotype. On the other hand, the role played by a heavily detrimental familial situation on the development and outcome, and possibly leading or contributing to a mild intellectual disability, should be taken into account. [ABSTRACT FROM AUTHOR]

Brown adipose tissue uncoupling protein-1 (UCP1) plays a major role in the control of energy balance in rodents. It has long been thought, however, that there is no physiologically relevant UCP1 expression in adult humans. In this study we show, using an original approach consisting of sorting cells from various tissues and differentiating them in an adipogenic medium, that a stationary population of skeletal muscle cells expressing the CD34 surface protein can differentiate in vitro into genuine brown adipocytes with a high level of UCP1 expression and uncoupled respiration. These cells can be expanded in culture, and their UCP1 mRNA expression is strongly increased by cell-permeating cAMP derivatives and a peroxisome-proliferator-activated receptor- γ (PPARγ) agonist. Furthermore, UCP1 mRNA was detected in the skeletal muscle of adult humans, and its expression was increased in vivo by PPARγ agonist treatment. All the studies concerning UCP1 expression in adult humans have until now been focused on the white adipose tissue. Here we show for the first time the existence in human skeletal muscle and the prospective isolation of progenitor cells with a high potential for UCP1 expression. The discovery of this reservoir generates a new hope of treating obesity by acting on energy dissipation. [ABSTRACT FROM AUTHOR]

Abstract: Genomic imprinting is a conserved epigenetic phenomenon in eutherian mammals, with regards both to the genes that are imprinted and the mechanism underlying the expression of just one of the parental alleles. Epigenetic modifications of alleles of imprinted genes are established during oogenesis and spermatogenesis, and these modifications are then inherited. Differentially methylated domains (DMDs) of imprinted genes are the genomic sites of these inherited epigenetic imprints. We previously showed that CpG-rich imperfect tandem direct repeats within three different mouse DMDs (Snurf/Snrpn, Kcnq1 and Igf2r), each with a unique sequence, play a central role in maintaining the differential methylation. This finding implicates repeat-related DNA structure, not sequence, in the imprinting mechanism. To better define the important features of this signal, we compared sequences of these three DMD tandem repeats among mammalian species. All DMD repeats contain short indirect repeats, many of which are organized into larger unit repeats. Even though the larger repeat units undergo deletion and addition during evolution (most likely through unequal crossovers during meiosis), the size of DMD tandem repeated regions has remained remarkably stable during mammalian evolution. Moreover, all three DMD tandem repeats have a high-CpG content, an ordered arrangement of CpG dinucleotides, and similar predicted secondary structures. These observations suggest that a structural feature or features of these DMD tandem repeats is the conserved DMD imprinting signal. [Copyright &y& Elsevier]

Assisted reproductive techniques (ARTs) have been widely used over the past two decades to help infertile couples conceive. Recent studies on the ART-conceived population have raised concern about the possible risks of these techniques, in particular with regard to increased incidence of growth and developmental disorders. Some of these effects might be linked to genomic imprinting defects, although current evidence does not allow definite conclusions to be drawn. This review summarises studies that have examined effects of gamete and embryo manipulations on imprinted genes, and discusses the evidence for and against effects of ARTs on offspring health, and in particular imprinting-related conditions. [ABSTRACT FROM PUBLISHER]

Imprinted genes exhibit a parent-of-origin specific pattern of expression. Such genes have been shown to be targets of molecular defects in particular genetic syndromes such as Beckwith-Wiedemann and Angelman syndromes. Recent reports have raised concern about the possibility that assisted reproduction techniques, such as in vitro fertilization or intracytoplasmic sperm injection, might cause genomic imprinting disorders. The number of reported cases of those disorders is still too small to draw firm conclusions and the safety of these widely used assisted reproduction techniques needs to be further evaluated. [ABSTRACT FROM AUTHOR]

Purpose: Hearing loss is characterized by an extensive genetic heterogeneity and remains a common disorder in children. Molecular diagnosis is of particular benefit in children, and permits the early identification of clinically-unrecognized hearing loss syndromes, which permits effective clinical management and follow-up, including genetic counselling. Methods: We performed whole-exome sequencing with the analysis of a panel of 189 genes associated with hearing loss in a prospective cohort of 61 children and 9 adults presenting mainly with isolated hearing loss. Results: The overall diagnostic rate using exome sequencing was 47.2% (52.5% in children; 22% in adults). In children with confirmed molecular results, 17/32 (53.2%) showed autosomal recessive inheritance patterns, 14/32 (43.75%) showed an autosomal dominant condition, and one case had X-linked hearing loss. In adults, the two patients showed an autosomal dominant inheritance pattern. Among the 32 children, 17 (53.1%) had nonsyndromic hearing loss and 15 (46.7%) had syndromic hearing loss. One adult was diagnosed with syndromic hearing loss and one with nonsyndromic hearing loss. The most common causative genes were STRC (5 cases), GJB2 (3 cases), COL11A1 (3 cases), and ACTG1 (3 cases). Conclusions: Exome sequencing has a high diagnostic yield in children with hearing loss and can reveal a syndromic hearing loss form before other organs/systems become involved, allowing the surveillance of unrecognized present and/or future complications associated with these syndromes. [ABSTRACT FROM AUTHOR]

Landmark features of imprinted genes are differentially methylated domains (DMDs), in which one parental allele is methylated on CpG dinucleotides and the opposite allele is unmethylated. Genetic experiments in the mouse have shown that DMDs are required for the parent-specific expression of linked clusters of imprinted genes. To understand the mechanism whereby the differential methylation is established and maintained, we analyzed a series of transgenes containing DMD sequences and showed that imperfect tandem repeats from DMDs associated with the Snurf/Snrpn, Kcnq1, and Igf2r gene clusters govern transgene imprinting. For the Igf2r DMD the minimal imprinting signal is two unit copies of the tandem repeat. This imprinted transgene behaves identically to endogenous imprinted genes in Dnmt1o and Dnmt3L mutant mouse backgrounds. The primary function of the imprinting signal within the transgene DMD is to maintain, during embryogenesis and a critical period of genomic reprogramming, parent-specific DNA methylation states established in the germ line. This work advances our understanding of the imprinting mechanism by defining a genomic signal that dependably perpetuates an epigenetic state during postzygotic development. [ABSTRACT FROM AUTHOR]

Biallelic loss-of-function variants in STRC contribute to mild-moderate hearing loss (DFNB16). Here, we report a female patient with mild hearing loss. Exome sequencing and MLPA analysis revealed STRC biallelic inactivation due to a nonsense and a CKMT1B - STRC deletion. Analysis of the self-reported normal-hearing parents revealed inconsistent M endelian inheritance. Indeed, the mother was a heterozygous carrier of a CKTM1B-STRC-CATSPER2 deletion, and the father shared the same genotype as his daughter. He was later found to also have mild-moderate hearing loss. To address these discrepancies, we used long-read sequencing and optical genome mapping. We demonstrated that the father, in fact, carried a CKMT1B-STRC-CATSPER2 deletion in trans with the STRC nonsense variant and a tandem duplication of CATSPER2-CKMT1A. The proband inherited this latter haplotype, together with the maternal CKMT1B-STRC-CATSPER2 deletion. Combining these two technologies allowed us to fully elucidate the complex structural rearrangements at the STRC locus and provide appropriate genetic counselling. [ABSTRACT FROM AUTHOR]

Abstract: Chromosomal imbalances, recognized as the major cause of mental retardation (MR), are often due to submicroscopic deletions or duplications not evidenced by conventional cytogenetic methods. Array-based comparative genomic hybridization (array-CGH) improves considerably the detection rate of submicroscopic chromosomal abnormalities and has proven to be an effective tool for detection of submicroscopic chromosome abnormalities in children with MR and/or multiple congenital defects. Observations of array-CGH deletions in defined chromosomal regions linked to a clinical phenotype will more and more allow to define genotype–phenotype correlations. We report here the case of a 10-year-old female with a de novo 7. 8Mb deletion in the 6q13–6q14.1 ascertained by array-CGH. The clinical features of this patient include psychomotor and language delay associated with minor dysmorphic features. [Copyright &y& Elsevier]

Abstract: We report here a three generations family with nevoid basal cell carcinoma syndrome (NBCCS) in which the diagnosis was made only after a second trimester of pregnancy ultrasonography revealing fetal cranio-cerebral malformations. A mutation was subsequently characterized in the aborted fetus, as well as in the mother, sister and grand-mother as an 18bp deletion in exon 15 of the patched homologue 1 (PTCH1) gene. MC1R gene sequencing identified in two NBCCS patients affected by multiple basal cell carcinomas a functional MC1R variant, D294H, previously shown to be associated with skin cancer risk. This variant was absent in the NBCCS patient that did not develop basal cell carcinomas, suggesting that this variant could have favored the development of skin cancers, in patients carrying the PTCH1 mutation. [Copyright &y& Elsevier]