Perinatal Tissue-Derived Stem Cells: An Emerging Therapeutic Strategy for Challenging Neurodegenerative Diseases.

Over the past 20 years, stem cell therapy has been considered a promising option for treating numerous disorders, in particular, neurodegenerative disorders. Stem cells exert neuroprotective and neurodegenerative benefits through different mechanisms, such as the secretion of neurotrophic factors, cell replacement, the activation of endogenous stem cells, and decreased neuroinflammation. Several sources of stem cells have been proposed for transplantation and the restoration of damaged tissue. Over recent decades, intensive research has focused on gestational stem cells considered a novel resource for cell transplantation therapy. The present review provides an update on the recent preclinical/clinical applications of gestational stem cells for the treatment of protein-misfolding diseases including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). However, further studies should be encouraged to translate this promising therapeutic approach into the clinical setting.

AEC and AFMSC Transplantation Preserves Fertility of Experimentally Induced Rat Varicocele by Expressing Differential Regenerative Mechanisms.

Amniotic membrane and amniotic fluid derived cells are regarded as a promising stem cell source for developing regenerative medicine techniques, although they have never been tested on male infertility diseases such as varicocele (VAR). The current study aimed to examine the effects of two distinct cell sources, human Amniotic Fluid Mesenchymal Stromal Cells (hAFMSCs) and amniotic epithelial cells (hAECs), on male fertility outcomes in a rat induced VAR model. To explain cell-dependent enhancement of reproductive outcomes in rats transplanted with hAECs and hAFMSCs, insights on testis morphology, endocannabinoid system (ECS) expression and inflammatory tissue response have been carried out alongside cell homing assessment. Both cell types survived 120 days post-transplantation by modulating the ECS main components, promoting proregenerative M2 macrophages (Mφ) recruitment and a favorable anti-inflammatory IL10 expression pattern. Of note, hAECs resulted to be more effective in restoring rat fertility rate by enhancing both structural and immunoresponse mechanisms. Moreover, immunofluorescence analysis revealed that hAECs contributed to CYP11A1 expression after transplantation, whereas hAFMSCs moved towards the expression of Sertoli cell marker, SOX9, confirming a different contribution into the mechanisms leading to testis homeostasis. These findings highlight, for the first time, a distinct role of amniotic membrane and amniotic fluid derived cells in male reproduction, thus proposing innovative targeted stem-based regenerative medicine protocols for remedying high-prevalence male infertility conditions such as VAR.

BRCA1/2 pathogenetic variant carriers and reproductive decisions: Gender differences and factors associated with the choice of preimplantation genetic diagnosis (PGD) and prenatal diagnosis (PND).

PURPOSE: To investigate the way carriers of a BRCA1/2 pathogenetic variant make their reproductive decisions and to examine the factors associated with the choice of preimplantation genetic diagnosis (PGD) and prenatal diagnosis (PND). METHODS: We conducted a comprehensive literature search in PubMed, Scopus, and Web of Science in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. RESULTS: A total of 16 articles published from 2000 to 2021 were included in this review. Data were overall collected from 3564 participants (86% females). Three important themes were identified across studies: changes in family planning, factors associated with family plans, and with acceptance or regret of PGD and PND. CONCLUSION: This review may contribute to the knowledge of the experience of those who have a BRCA1/2 mutation and want a child. These results may help genetic counselors and healthcare professionals that support people with a BRCA pathogenetic variant with reproductive issues.

Human amniotic fluid stem cells are able to form embryoid body-like aggregates which performs specific functions: morphological evidences.

Human second trimester Amniotic Fluid Stem Cells (hAFSCs) harbour the potential to differentiate into cells of each of the three germ layers and to form Embryoid Body (EB)-like aggregates, without inducing teratoma formation and with no ethical concerns. However, in spite of the number of reports on hAFSCs-EBs and their characterization, a thorough evaluation in light and electron microscopy of morphological and morphometric features of hAFSCs-EBs development in vitro has not been reported yet. Apart from a superficial layer of epithelial-like flat cells, displaying rare microvilli on the free surface, hAFSCs-EBs enclose inner material, abundant in vesicles and secretory granules, showing early characteristics of connective extracellular matrix dispersed among different types of inner cells. The observation of a number of microvesicles mainly represented by microparticles and, to a lower extent, by exosomes indicates the presence of a complex cellular communication system within this structure. According to morphological analysis, after 7 days of in vitro culture hAFSCs-EB appears as a well-organized corpuscle, sufficiently young to be a carrier of stemness and at the same time, when appropriately stimulated, able to differentiate. In fact, 7-day hAFSCs-EB represents itself an initial cellular transformation towards a specialized structure both in recording and in providing different stimuli from the surrounding environment, organizing structures and cells towards a differentiation fate.

Rat bone healing induced by natural nanocrystalline carbonated hydroxyapatite in combination with human amniotic fluid stem cells (AFSCs).

The present study was aimed at identifying a new scaffold/stem cell combination useful to treat large bone defects. Human amniotic fluid stem cells (AFSCs) were expanded in vitro, labeled with a fluorescent cell-permeable dye (PKH26) and transplanted in vivo in a femoral injured rat model. The femoral defect was left untreated (control rats) or filled with hydroxyapatite (HA; natural nanocrystalline carbonated hydroxyapatite-Orthoss®) scaffold alone or loaded with PKH26-labeled AFSCs. All animals were killed 3 weeks after implantation. Both gross anatomy and histological observations revealed a major bone regenerative response in rat specimens treated with HA scaffold, alone or supplemented with AFSCs. Samples injected with HA plus AFSCs displayed the presence of abundant fibrotic tissue, the formation of periosteal woven bone, and an increased presence of blood vessels in the bone marrow, with still fluorescent AFSCs in close proximity. These observations provide evidence that natural HA plus AFSCs represents a promising alternative therapeutic strategy to autologous bone grafting procedures.

Yq Microdeletion in a Patient with VACTERL Association and Shawl Scrotum with Bifid Scrotum: A Real Pathogenetic Association or a Coincidence?

VACTERL association is defined by the occurrence of congenital malformations: vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula with esophageal atresia, radial and renal dysplasia, and limb defects. No genetic alterations have been discovered except for some sporadic chromosomal rearrangements and gene mutations. We report a boy with VACTERL association and shawl scrotum with bifid scrotum who presented with a de novo Yq11.223q11.23 microdeletion identified by array CGH. The deletion spans 3.1 Mb and encompasses several genes in the AZFc region, frequently deleted in infertile men with severe oligozoospermia or azoospermia. Herein, we discuss the possible explanation for this unusual genotype-phenotype correlation. We suggest that the deletion of the BPY2 (previously VCY2) gene, located in the AZFc region and involved in spermatogenesis, contributed to the genesis of the phenotype. In fact, BPY2 interacts with a ubiquitin-protein ligase, involved in the SHH pathway which is known to be implicated in the genesis of VACTERL association.

The role of depression and emotion regulation on parenting stress in a sample of mothers with cancer.

PURPOSE: The aim of the current study was to investigate if and to what extent depression and emotional regulation strategies (namely, cognitive reappraisal and expressive suppression) might lead to parenting stress in a sample of mothers with cancer and in a sample of healthy mothers. METHODS: A sample of mothers with cancer (clinical group; n = 64) and a sample of healthy mothers (control group; n = 80) were administered self-report questionnaires investigating parenting stress (the parenting stress index), depressive symptoms (the Zung depression self-rating scale) and emotion regulation strategies (the emotion regulation questionnaire). RESULTS: Depressive levels represented the most significant predictor of maternal parenting stress in both groups (p < .001). In addition, cognitive reappraisal (p < .05) but not expressive suppression significantly predicted parenting stress exclusively in the group of mothers with cancer. Finally, cognitive reappraisal was negatively and significantly associated with time since cancer diagnosis to survey. CONCLUSIONS: This study highlights that depressive levels and cognitive reappraisal may play a significant role in parenting stress. The systematic assessment of these variables in women with an oncological diagnosis might help mental health professionals to identify those mothers at risk of developing higher levels of parenting stress ensuring adequate support and preventing negative effects on the parent-child relationship.

Psychological aspects, risk and protective factors related to BRCA genetic testing: a review of the literature.

PURPOSE: The primary aim of the present study was to conduct a systematic review of short-, intermediate- and long-term psychological effects, such as anxiety, depression and distress, on individuals undergoing genetic testing to determine BRCA1 and BRCA2 gene mutation. The different instruments used for the measurement of each construct were reported. In addition, risk and protective factors associated with psychological outcomes of genetic tests were explored. METHODS: Bibliographic databases were searched for studies published over the period 1998-2018. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method, 21 articles were selected for the current review. RESULTS: Overall, the collected data revealed rather diverse results, although most studies reported higher levels of distress, anxiety and depression in carriers, as compared to non-carriers. The two genders were not equally represented, with men constituting only 6% of the sample. Risk factors and protective factors that may influence psychological outcomes and adjustment to genetic tests are highlighted and discussed in this review. CONCLUSIONS: The increased risk of developing cancer associated with positive genetic testing results may be experienced as traumatic by many patients, although not all individuals with positive genetic testing results will experience increased distress. Hence, future studies should consider specific risk factors in order to select those who are more likely to be in need of psychological support. Finally, it is necessary to increase the number of male samples to better understand the male experience related to genetic testing outcomes.

Impact of lysosomal storage disorders on biology of mesenchymal stem cells: Evidences from in vitro silencing of glucocerebrosidase (GBA) and alpha-galactosidase A (GLA) enzymes.

Lysosomal storage disorders (LDS) comprise a group of rare multisystemic diseases resulting from inherited gene mutations that impair lysosomal homeostasis. The most common LSDs, Gaucher disease (GD), and Fabry disease (FD) are caused by deficiencies in the lysosomal glucocerebrosidase (GBA) and alpha-galactosidase A (GLA) enzymes, respectively. Given the systemic nature of enzyme deficiency, we hypothesized that the stem cell compartment of GD and FD patients might be also affected. Among stem cells, mesenchymal stem cells (MSCs) are a commonly investigated population given their role in hematopoiesis and the homeostatic maintenance of many organs and tissues. Since the impairment of MSC functions could pose profound consequences on body physiology, we evaluated whether GBA and GLA silencing could affect the biology of MSCs isolated from bone marrow and amniotic fluid. Those cell populations were chosen given the former's key role in organ physiology and the latter's intriguing potential as an alternative stem cell model for human genetic disease. Our results revealed that GBA and GLA deficiencies prompted cell cycle arrest along with the impairment of autophagic flux and an increase of apoptotic and senescent cell percentages. Moreover, an increase in ataxia-telangiectasia-mutated staining 1 hr after oxidative stress induction and a return to basal level at 48 hr, along with persistent gamma-H2AX staining, indicated that MSCs properly activated DNA repair signaling, though some damages remained unrepaired. Our data therefore suggest that MSCs with reduced GBA or GLA activity are prone to apoptosis and senescence due to impaired autophagy and DNA repair capacity.

Comparison between CaGene 5.1 and 6.0 for BRCA1/2 mutation prediction: a retrospective study of 150 BRCA1/2 genetic tests in 517 families with breast/ovarian cancer.

During the past years, several empirical and statistical models have been developed to discriminate between carriers and non-carriers of germline BRCA1/BRCA2 (breast cancer 1, early onset/breast cancer 2, early onset) mutations in families with hereditary breast or ovarian cancer. Among these, the BRCAPRO or CaGene model is commonly used during genetic counseling, and plays a central role in the identification of potential carriers of BRCA1/2 mutations. We compared performance and clinical applicability of BRCAPRO version 5.1 vs version 6.0 in order to assess diagnostic accuracy of updated version. The study was carried out on 517 pedigrees of patients with familial history of breast or ovarian cancer, 150 of which were submitted to BRCA1/2 mutation screening, according to BRCAPRO evaluation or to criteria based on familial history. In our study, CaGene 5.1 was more sensitive than CaGene 6.0, although the latter showed a higher specificity. Both BRCAPRO versions better discriminate BRCA1 than BRCA2 mutations. This study evidenced similar performances in the two BRCAPRO versions even if the CaGene 6.0 has underestimated the genetic risk prediction in some BRCA mutation-positive families. Genetic counselors should recognize this limitation and during genetic counseling would be advisable to use a set of criteria in order to improve mutation carrier prediction.

BESTROPHINOPATHY: A Spectrum of Ocular Abnormalities Caused by the c.614T>C Mutation in the BEST1 Gene.

PURPOSE: To describe the variable ocular phenotype associated with a heterozygous mutation in the BEST1 gene. METHODS: Clinical and genetic assessment was performed in five members of the same family. Molecular genetic analysis of the BEST1 gene was performed by direct sequencing. Extensive ophthalmic examination included color fundus imaging, spectral domain optical coherence tomography, fundus autofluorescence, electro-oculography (EOG), and full-field electroretinography (ERG). The main outcome measures were BEST1 mutations, imaging, and electroretinography findings. RESULTS: All affected family members carried a single heterozygous c.614T>C (p.I205T) mutation in exon 5 of the BEST1 gene. The 46-year-old proband showed nanophthalmos with chorioretinal atrophy in the macula, extensive coarse hyperpigmentation in the (mid) peripheral retina with tractional vitreous strands. Full-field ERG revealed nonrecordable cone and rod responses, and EOG showed an absent light rise. The daughter and son of the proband showed a phenotype resembling autosomal recessive bestrophinopathy, including short axial lengths, cystoid fluid collections, and shallow serous subretinal fluid accumulation on spectral domain optical coherence tomography throughout the macula in combination with mild retinal pigment epithelium changes. The son of the proband also showed subretinal yellowish deposits inferiorly in the macula as well as outside the temporal vascular arcade, that were hyperfluorescent on fundus autofluorescence, similar to those seen in autosomal recessive bestrophinopathy. Full-field ERG revealed a reduced rod and cone response and a markedly reduced or absent EOG light peak in both brother and sister of the proband. CONCLUSION: The clinical spectrum of bestrophinopathy may encompass severe ocular phenotypes that affect the development and function of the entire eye. A clinical picture similar to autosomal recessive bestrophinopathy can also be caused by a single heterozygous mutation in the BEST1 gene, such as the c.614T>C (p.I205T) variant in this family.

Amniotic Fluid Stem Cells: A Novel Source for Modeling of Human Genetic Diseases.

In recent years, great interest has been devoted to the use of Induced Pluripotent Stem cells (iPS) for modeling of human genetic diseases, due to the possibility of reprogramming somatic cells of affected patients into pluripotent cells, enabling differentiation into several cell types, and allowing investigations into the molecular mechanisms of the disease. However, the protocol of iPS generation still suffers from technical limitations, showing low efficiency, being expensive and time consuming. Amniotic Fluid Stem cells (AFS) represent a potential alternative novel source of stem cells for modeling of human genetic diseases. In fact, by means of prenatal diagnosis, a number of fetuses affected by chromosomal or Mendelian diseases can be identified, and the amniotic fluid collected for genetic testing can be used, after diagnosis, for the isolation, culture and differentiation of AFS cells. This can provide a useful stem cell model for the investigation of the molecular basis of the diagnosed disease without the necessity of producing iPS, since AFS cells show some features of pluripotency and are able to differentiate in cells derived from all three germ layers "in vitro". In this article, we describe the potential benefits provided by using AFS cells in the modeling of human genetic diseases.

Calcitonin-induced effects on amniotic fluid-derived mesenchymal stem cells.

BACKGROUND/AIMS: Mesenchymal stem cells from human amniotic fluid (huAFMSCs) can differentiate into multiple lineages and are not tumorigenic after transplantation, making them good candidates for therapeutic purposes. The aim was to determine the effects of calcitonin on these huAFMSCs during osteogenic differentiation, in terms of the physiological role of calcitonin in bone homeostasis. METHODS: For huAFMSCs cultured under different conditions, we assayed: expression of the calcitonin receptor, using immunolabelling techniques; proliferation and osteogenesis, using colorimetric and enzymatic assays; intracellular Ca(2+) and cAMP levels, using videomicroscopy and spectrophotometry. RESULTS: The calcitonin receptor was expressed in proliferating and osteo-differentiated huAFMSCs. Calcitonin triggered intracellular Ca(2+) increases and cAMP production. Its presence in cell medium also induced dose-dependent inhibitory effects on proliferation and increased osteogenic differentiation of huAFMSCs, as also indicated by enhancement of specific markers and alkaline phosphatase activity. CONCLUSIONS: These data show that huAFMSCs represent a potential osteogenic model to study in-vitro cell responses to calcitonin (and other members of the calcitonin family). This leads the way to the opening of new lines of research that will add new insight both in cell therapies and in the pharmacological use of these molecules.

The MTRR 66A>G polymorphism and maternal risk of birth of a child with Down syndrome in Caucasian women: a case-control study and a meta-analysis.

We performed a large case-control study and a meta-analysis of the literature to address the role of the methionine synthase reductase (MTRR) c.66A>G polymorphism as a maternal risk factor for the birth of a child with Down Syndrome (DS) among Caucasian women. A total of 253 mothers of a DS child (MDS) and 298 control mothers of Italian origin were included in the case-control study. The meta-analysis of previous and present data involved a total of seven studies performed in Caucasian populations (971 MDS and 1,387 control mothers). Results from the meta-analysis indicated overall a positive significant association between MTRR c.66A>G genotype [OR 1.36 (95 % CI 1.10-1.68), dominant model] and allele frequencies [OR 1.26 (95 % CI 1.04-1.51), allele contrast model] and maternal risk of birth of a child with DS. A sensitivity analysis revealed some interesting differences between Europeans, Caucasians of European descent, and inhabitants of Mediterranean regions, suggesting the possibility of population-specific modifying factors. The case-control study revealed association of the polymorphism with increased folate levels, and a possible interaction with the methionine synthase (MTR) c.2756A>G one, that resulted in a borderline significant maternal risk of birth of a child with DS for the double heterozygous MTR 2756AG/MTRR 66AG genotype [OR 1.79 (95 % CI 1.00-3.18)]. Overall, present data suggest that the MTRR c.66A>G polymorphism represents a risk factor for the birth of a child with DS among white Caucasian women. However, the combined presence of other genetic factors and interactions with geographic and environmental ones, can modify the effect of the single polymorphism alone, leading to population specific effect sizes.

Nicotine-induced Genetic and Epigenetic Modifications in Primary Human Amniotic Fluid Stem Cells.

BACKGROUND: Smoking during pregnancy has been linked to adverse health outcomes in offspring, but the underlying mechanisms are not fully understood. To date, the effect of maternal smoking has been tested in primary tissues and animal models, but the scarcity of human tissues limits experimental studies. Evidence regarding smoking-related molecular alteration and gene expression profiles in stem cells is still lacking. METHODS: We developed a cell culture model of human amniotic fluid stem cells (hAFSCs) of nicotine (NIC) exposure to examine the impact of maternal smoking on epigenetic alterations of the fetus. RESULTS: NIC 0.1 µM(equivalent to "light" smoking, i.e., 5 cigarettes/day) did not significantly affect cell viability; however, significant alterations in DNA methylation and N6-methyladenosine (m6A) RNA methylation in hAFSCs occurred. These epigenetic changes may influence the gene expression and function of hAFSCs. Furthermore, NIC exposure caused time-dependent alterations of the expression of pluripotency genes and cell surface markers, suggesting enhanced cell stemness and impaired differentiation potential. Furthermore, NICtreated cells showed reduced mRNA levels of key adipogenic markers and hypomethylation of the promoter region of the imprinted gene H19 during adipogenic differentiation, potentially suppressing adipo/lipogenesis. Differential expression of 16 miRNAs, with predicted target genes involved in various metabolic pathways and linked to pathological conditions, including cognitive delay and fetal growth retardation, has been detected. CONCLUSIONS: Our findings highlight multi-level effects of NIC on hAFSCs, including epigenetic modifications, altered gene expression, and impaired cellular differentiation, which may contribute to long-term consequences of smoking in pregnancy and its potential impact on offspring health and development.

The Crucial Role of Hereditary Cancer Panel Testing in Unaffected Individuals with a Strong Family History of Cancer: A Retrospective Study of a Cohort of 103 Healthy Subjects.

Hereditary cancer syndromes caused by germline mutations account for 5-10% of all cancers. The finding of a genetic mutation could have far-reaching consequences for pharmaceutical therapy, personalized prevention strategies, and cascade testing. According to the National Comprehensive Cancer Network's (NCCN) and the Italian Association of Medical Oncology (AIOM) guidelines, unaffected family members should be tested only if the affected one is unavailable. This article explores whether germline genetic testing may be offered to high-risk families for hereditary cancer even if a living affected relative is missing. A retrospective study was carried out on 103 healthy subjects tested from 2017 to 2023. We enrolled all subjects with at least two first- or second-degree relatives affected by breast, ovarian, pancreatic, gastric, prostate, or colorectal cancer. All subjects were tested by Next Generation Sequencing (NGS) multi-gene panel of 27 cancer-associated genes. In the study population, 5 (about 5%) pathogenic/likely pathogenic variants (PVs/LPVs) were found, while 40 (42%) had a Variant of Uncertain Significance (VUS). This study highlights the importance of genetic testing for individuals with a strong family history of hereditary malignancies. This approach would allow women who tested positive to receive tailored treatment and prevention strategies based on their personal mutation status.

Role of CES1 and ABCB1 Genetic Polymorphisms on Functional Response to Dabigatran in Patients with Atrial Fibrillation.

Background: Dabigatran etexilate is a pro-drug hydrolyzed into dabigatran by carboxylesterases (CES) and is a substrate of the P-Glycoprotein encoded by the adenosine-triphosphate-binding cassette sub-family B member (ABCB)1 genes. We evaluated the functional response to dabigatran according to different CES1 and ABCB1 single-nucleotide polymorphisms (SNPs) in patients with atrial fibrillation (AF). Methods: A total of 100 consecutive patients with AF taking dabigatran were enrolled by two Italian centers. A venous blood sample was drawn for genetic determinations, as well as a measurement of the diluted thrombin time (dTT) and drug plasma concentrations, at the trough and peak. The main objective was the relationship between the dTT values and CES1 rs2244613, CES1 rs8192935 and ABCB1 rs4148738 SNP while on two different dabigatran doses (110 and 150 mg BID). Results: A total of 43 patients were on a 110 mg dabigatran dose and 57 on 150 mg. The DTT values at the trough and at peak were not different among patients with different CES1 rs2244613 and CES1 rs8192935 genotypes, regardless of the dabigatran dose. In patients on 150 mg dabigatran, the dTT values at the trough were 77 (44-111) ng/mL in patients with the ABCB1 rs4148738 heterozygous CT genotype vs. 127 (85-147) ng/mL in the wild-type CC genotype vs. 110 (47-159) ng/mL in the mutant trait TT genotype (p = 0.048). In patients with the ABCB1 rs4148738 CT genotype, OR for having dTT values at a trough below the median was 3.21, 95% CI 1.04-9.88 (p = 0.042). Conclusions: ABCB1 rs4148738 CT heterozygous is associated with the reduced anticoagulant activity of dabigatran at the trough in patients receiving the higher dose regimen.

MS-MLPA analysis for FMR1 gene: evaluation in a routine diagnostic setting.

BACKGROUND: Fragile X Syndrome (FXS), the most common cause of familiar mental retardation, is associated in over 99% of cases to an expansion over 200 repeats of a CGG sequence in the 5' UTR of the FMR1 gene (Xq27.3), leading to the hypermethylation of the promoter. Molecular diagnosis of FXS have been so far based on the use of the Southern Blot (SB) analysis, a low throughput and time consuming technique. In order to update the diagnostic approach for FXS, we evaluated the usefulness of the Methylation-Specific Multiplex-Ligation-dependent Probe Amplification assay (MS-MLPA). METHODS: The study was carried out by retrospectively analysing 44 male patients, 10 Chorionic Villus Sampling (CVS) samples and 10 females previously analyzed by SB. In addition, a prospective study on 98 male subjects, 20 females and 1 CVS sample was carried out for assessing the feasibility and the impact of MS-MLPA in a routine lab work. RESULT: Results provided by both the retrospective and the prospective parts of this study strongly demonstrate the robustness and reproducibility of the MS-MLPA assay, able to correctly detect the methylation status in all normal and full mutation male samples analyzed, including CVS male samples. On the other hand, MS-MLPA analysis on females samples produced unreliable results. CONCLUSION: Based on our results, we suggest the necessity of a separate workflow for male and female patients with suspected FXS in the routine diagnostic setting. MS-MLPA, in combination with CGG repeat sizing using a single-tube primed FMR1 PCR, represents a reliable diagnostic protocol in the molecular diagnosis of FXS male patients.

DNMT3B promoter polymorphisms and maternal risk of birth of a child with Down syndrome.

STUDY QUESTION: Are DNMT3B promoter polymorphisms among maternal risk factors for the birth of a child with Down syndrome (DS)? SUMMARY ANSWER: Present results suggest that combinations of functional DNMT3B promoter polymorphisms might modulate maternal risk of birth of a child with DS. WHAT IS KNOWN ALREADY: The DNMT3B gene codes for DNA methyltransferase 3b (DNMT3b), a protein required for genome-wide de novo methylation, for the establishment of DNA methylation patterns during development and for regulating the histone code and DNA methylation at centromeric regions. Two common functional DNMT3B promoter polymorphisms, namely -149 C > T (rs2424913) and -579 G > T (rs1569686), have been extensively investigated in cancer genetic association studies but less is known about their role in non-cancer diseases. Early in 1999, it was supposed that impaired DNA methylation of pericentromeric regions might represent a maternal risk factor for having a baby with DS. STUDY DESIGN, SIZE AND DURATION: We aimed to investigate DNMT3B -149 C > T and -579 G > T polymorphisms as maternal risk factors for the birth of a child with DS. The study was performed on DNA samples from 172 mothers of DS individuals (135 aged <35 years when they conceived) and 157 age-matched mothers of unaffected individuals. PARTICIPANTS/MATERIALS, SETTING AND METHODS: Genotyping was performed by means of the PCR-RFLP technique. MAIN RESULTS AND THE ROLE OF CHANCE: The DNMT3B -579T allele [odds ratio (OR) = 0.68; 95% confidence interval (CI) = 0.48-0.94, P = 0.02], the DNMT3B -579 GT genotype (OR = 0.55; 95% CI = 0.35-0.87 , P = 0.01) and the combined DNMT3B -579 GT + TT genotype (OR = 0.55; 95% CI = 0.36-0.86 , P = 0.008) were associated with reduced risk of birth of a child with DS. A joint effect of the two polymorphisms was observed and the combined -579 GT/-149 CC genotype resulted in decreased DS risk (OR = 0.22; 95% CI = 0.08-0.64, P = 0.003). The effect remained statistically significant after Bonferroni's correction for multiple comparisons. Similar results were obtained when the analysis was restricted to women who conceived a DS child before 35 years of age. LIMITATIONS AND REASONS FOR CAUTION: To the best of our knowledge, this is the first genetic association study aimed at evaluating DNMT3B polymorphisms as maternal risk factors for DS. Replication of the findings in other populations is required. WIDER IMPLICATIONS OF THE FINDINGS: If confirmed in subsequent studies, DNMT3B promoter polymorphisms might be additional markers to be taken into account when evaluating the contribution of one-carbon (folate) metabolism to the maternal risk of birth of a child with DS.

The MTR 2756A>G polymorphism and maternal risk of birth of a child with Down syndrome: a case-control study and a meta-analysis.

Methionine synthase (MTR) is required for the conversion of homocysteine (hcy) to methionine in the one-carbon metabolic pathway. Previous studies investigating a common MTR 2756A>G polymorphism as a maternal risk factor for the birth of a child with Down syndrome (DS) are conflicting and limited by small case-control cohorts, and its contribution to circulating hcy levels is still debated. We performed a large case-control study and a meta-analysis of the literature to further address the role of MTR 2756A>G as a maternal risk factor for the birth of a child with DS. 286 mothers of a DS child (MDS) and 305 control mothers of Italian origin were included in the case-control study. Genotyping was performed by means of PCR/RFLP technique. Data on circulating levels of hcy, folates, and vitamin B12 were available for 189 MDS and 194 control mothers. The meta analysis of previous and present data involved a total of 8 studies (1,171 MDS and 1,402 control mothers). Both the case-control study and the meta-analysis showed no association of MTR 2756A>G with the maternal risk of birth of a child with DS (OR = 1.15; 95 % CI 0.85-1.55, and OR = 1.08; 95 % CI 0.93-1.25, respectively), even after stratification of the overall data available for the meta-analysis into ethnic groups. No association of the studied polymorphism with circulating levels of hcy, folates, and vitamin B12 was observed. Present data do not support a role for MTR 2756A>G as independent maternal risk factor for a DS birth.