Prenatal Genetic Counseling Research Articles

Genetic Characterization of a Cohort of Italian Patients with Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency.

Defects in the steroid 21-hydroxylase gene (CYP21A2) cause 21-hydroxylase deficiency (21OHD), the main cause of congenital adrenal hyperplasia (CAH). The disease shows a broad spectrum of clinical forms, ranging from severe or classical (salt wasting, SW, and simple virilizing, SV), to mild late onset or nonclassical (NC). 21OHD affects 1 in 15,000 in its severe classic form and 1 in 200-1000 in its mild NC form. There are many studies reporting the frequency of CYP21A2 pathogenic variants in different populations; however, few of them provide comprehensive information about Italian patients. Here, we present genetic results from a cohort of 245 unrelated Italian individuals with clinical diagnosis of CAH due to 21OHD. A specific polymerase chain reaction (PCR) protocol combined with Sanger sequencing was used for CYP21A2 analysis. The multiplex ligation-dependent probe amplification (MLPA) assay was employed for copy number variation (CNV) determination. One hundred fourteen (46.5%) of the index cases had the NC form, 57 (23.3%) had the SV form, and 74 (30.2%) presented the SW form of the disease. The most prevalent variant found in NC patients was the p.Val282Leu (51.3%), while the most frequent variants in the classical form were p.Ile173Asn (8.6%) and c.293-13C>G (26.0%). In our study, the frequency of large rearrangements was 15.3%, with CAH-X alleles representing 40% of all DEL/CONV. In addition, 12 alleles carried rare variants, and 1 had a novel variant p.(Arg342Gln). We observed phenotype-genotype correlation in 94.7% of cases. A complete concordance was observed in Groups 0 (enzyme activity completely impaired) where all patients had the SW form as expected. In Group A (0-1% residual enzyme activity), 78.4% of patients had the anticipated SW form while 21.6% were diagnosed with the SV form. Within Group B (~2% residual enzyme activity), 93.4% of patients exhibited SV form and 6.5% SW disease. Finally, 92.6% and 7.4% of patients belonging to Group C (enzyme partially impaired to ~20-60% residual activity) exhibited NC and SV phenotypes, respectively. This work, representing a comprehensive genetic study, expanded the CYP21A2 variants spectrum of Italian patients with 21OHD and could be helpful in prenatal diagnosis and genetic counseling.

Optical genome mapping in an atypical Pelizaeus-Merzbacher prenatal challenge.

Pathogenic genetic variants represent a challenge in prenatal counseling, especially when clinical presentation in familial carriers is atypical. We describe a prenatal case involving a microarray-detected duplication of PLP1 which causes X-linked Pelizaeus-Merzbacher disease, a progressive hypomyelinating leukodystrophy. Because of atypical clinical presentation in an older male child, the duplication was examined using a novel technology, optical genome mapping, and was found to be an inverted duplication, which has not been previously described. Simultaneously, segregation analysis identified another healthy adult male carrier of this unique structural rearrangement. The novel PLP1 structural variant was reclassified, and a healthy boy was delivered. In conclusion, we suggest that examining structural variants with novel methods is warranted especially in cases with atypical clinical presentation and may in these cases lead to improved prenatal and postnatal genetic counseling.

Screening and evaluation of TBX20 and CITED2 mutations in children with congenital cardiac septal defects: Correlation with cardiac troponin T and caspase-3

Congenital cardiac septal defect (CCSD) is the main type of congenital heart disease and owns a very high mortality rate among newborns. CCSD is controlled by specific transcription factors, including T-box transcription factor 20 (TBX20) and Cbp/P300 interacting transactivator with Glu/Asp rich carboxy-terminal domain 2 (CITED2) which are key molecular actors in heart development. Here, we screened for mutations in TBX20 and CITED2 genes in Egyptian children with CCSD and assessed their association with CCSD susceptibility and with cardiac troponin T (cTnT) and the apoptotic marker caspase-3 as biochemical markers for CCSD. Thirty unrelated newborns and children affected with CCSD and 30 matched healthy controls with no personal history of cardiac diseases were recruited. Selection criteria were children (<18 years) with any age diagnosed with CCSD using ECHO. Mutational analysis and genotyping were done using PCR-Sanger DNA sequencing technique. Serum cTnT and caspase-3 were analyzed using ELISA. Sequencing analysis identified 2 TBX20 variants (c.766T>C and c.39T>C) in the CCSD and control groups and 2 CITED2 variants (c.12T>C and c.9C>T) in one CCSD patient, while were absent in controls. In silico analysis identified TBX20 c.766T>C (rs3999941) as a missense (F256L) pathogenic variant and the other three variants as synonymous and benign. Compared with controls, TBX20 c.766T>C TC genotype and minor C allele were candidate high-risk factors for CCSD. Besides, serum cTnT and caspase-3 were dramatically elevated in CCSD children compared to controls. TBX20 c.766T>C TC genotype was associated with high cTnT in CCSD children. Conclusively, we advocate TBX20 c.766T>C variant as a potential genetic marker for CCSD which might associate with high cTnT levels. CITED2 genetic variants might have rare incidence among Egyptian CCSD children. Serum cTnT and caspase-3 are useful markers for ascertaining CCSD in children. These data could be exploited in prenatal genetic counseling, pre-implantation genotyping, and therapy of CCSD.

A balancing act: Non-directive communication, risk perceptions, and meeting patient needs in genetic counseling: A South African case study.

Genetic counseling (GC) traditionally follows a non-directive counseling approach. Although a cornerstone of GC teaching and theory, there has been debate on whether GC is, can be, or should be a patient-led service due to challenges in practice, as well as the advancement and complexity of genetic testing. Personal risk perceptions and patient expectations within particular contexts may further affect how genetic counselors discuss risk information, even while attempting to remain neutral. Less is known about the process of GC communication in non-Western settings. This paper presents empirical evidence from a South African prenatal GC consultation where tensions become apparent due to differing risk perceptions and expectations between a genetic counselor and a patient, which ultimately impacts non-directive communication practice. The case study forms part of a larger qualitative study focusing on risk and uncertainty communication within GC consultations in Cape Town, South Africa. A blended sociolinguistic approach drawing on principles of conversation analysis (CA) and theme-orientated discourse analysis (TODA) provides evidence of the complexity of imparting risk information and challenging patients to reflect on their decision-making, whilst refraining from sharing personal risk perceptions during everyday practice. The case study demonstrates how a genetic counselor may become implicitly and explicitly directive in their communication approach within the same consult which may reveal their personal risk perceptions on the matter discussed. In addition, the case study reveals how a genetic counselor may grapple with the dilemma of honoring the non-directive guidelines of the profession, whilst simultaneously supporting a patient who requests advice. The ongoing debate on non-directive counseling, decision-making, and patient care in GC is important for the reflection and development of the profession to understand how to assist and support patients facing sensitive and difficult decisions, in a meaningful, and contextually-tailored manner.

Essential genetic modifiers and their measurable impact in a community-recruited population analysis for non-severe hemoglobin E/β-thalassemia prenatal genetic counseling

The study aimed to identify essential phenotype-modulating factors among the pre-existence of several important ones and clarify their measurable impact on the clinical severity of hemoglobin (Hb) E/β-thalassemia in a community-recruited population analysis. This prospective study was designed to compare modifiers between community- (less or no symptoms) and hospital-recruited individuals with Hb E/β-thalassemia. The formerly included couples previously assessed for prenatal thalassemia at-risk status at 42 community and 7 referral hospitals in Thailand through on-site investigations between June 2020 and December 2021. The control included Hb E/β-thalassemia patients undergoing transfusions. The Mahidol score classified disease severity. Beta-globin, α0-thalassemia (-SEA, -THAI), α+-thalassemia (-α3.7, -α4.2), Hb Constant Spring (αCS) alleles, rs766432 in BCL11A, rs9399137 in HBS1L-MYB, and rs7482144-XmnI were evaluated. Modifiers were compared between 102 community- and 104 hospital-recruited cases. Alleles of β+, -SEA, -α3.7, αCS, and a minor allele of rs9399137 were prevalent in the community and mild severity groups (p < 0.05). Multiple linear regression analysis associated modulating alleles with −4.299 (-SEA), −3.654 (β+), −3.065 (rs9399137, C/C), −2.888 (αCS), −2.623 (‐α3.7), −2.361 (rs7482144, A/A), −1.258 (rs9399137, C/T), and −1.174 (rs7482144, A/G) severity score reductions (p < 0.05). Certain modifiers must be considered in routine prenatal genetic counseling for Hb E/β-thalassemia.

Experience in prenatal genetic testing and reproductive decision-making for monogenic disorders from a single tertiary care genetics clinic in a low-middle income country

ObjectivesExplore health-care seeking behaviour among couples with pregnancies at-risk of monogenic disorders and compare time duration for obtaining Prenatal Genetic Test (PGT) results based on (i) amniocentesis and Chorionic Villus Sampling (CVS) (ii) in-house testing and out-sourced testing. Report the spectrum of monogenic disorders in our cohort.MethodsMedical records of women consulting prenatal genetic counselling clinic at Aga Khan University Hospital, Karachi from December-2015 to March-2021 with history of miscarriage or a monogenic disorder in previous children were reviewed.ResultsForty-three pregnancies in 40 couples were evaluated, 37(93%) were consanguineous. Twenty-five (63%) couples consulted before and 15(37%) after conception. Thirty-one (71%) pregnancies underwent CVS at the mean gestational age of 13-weeks and 6-days ± 1-week and 3-days and amniocentesis at 16-weeks and 2-days ± 1-week and 4-days. PGT for 30 (70%) pregnancies was outsourced. The mean number of days for in-house PGT was 16.92 ± 7.80 days whereas for outsourced was 25.45 ± 7.7 days. Mean duration from procedure to PGT result was 20.55 days after CVS compared to 28.75 days after amniocentesis. Eight (18%) fetuses were homozygous for disease-causing variant for whom couples opted for termination of pregnancy (TOP). Twenty-six monogenetic disorders were identified in 40 families.ConclusionProactive health-care seeking behaviour and TOP acceptance is present amongst couples who have experienced a genetic disorder.

The pathogenic p.Gln319Ter variant is not causing congenital adrenal hyperplasia when inherited in one of the duplicated CYP21A2 genes.

The study aimed to identify the pathogenic status of p.Gln319Ter (NM_000500.7: c.955C>T) variant when inherited in a single CYP21A2 gene (bimodular RCCX haplotype) and to discriminate between a non-causing congenital adrenal hyperplasia (CAH) allele when inherited in a duplicated and functional CYP21A2 gene context (trimodular RCCX haplotype). 38 females and 8 males with hyperandrogenemia, previously screened by sequencing and identified as carriers for the pathogenic p.Gln319Ter, were herein tested by multiplex ligation-dependent probe amplification (MLPA) and a real-time PCR Copy number Variation (CNV) assay. Both MLPA and real-time PCR CNV analyses confirmed a bimodular and pathogenic RCCX haplotype with a single CYP21A2 in 19/46 (41.30%) p.Gln319Ter carriers and who in parallel all shared elevated 17-OHP levels. The remaining 27 individuals that also carried the p.Gln319Ter exhibited low 17-OHP levels as a result of their carriership of a duplicated CYP21A2 with a trimodular RCCX haplotype. Interestingly, all of these individuals also carried in linkage disequilibrium with p.Gln319Ter two single nucleotide polymorphisms, the c.293-79G>A (rs114414746) in intron 2 and the c.*12C>T (rs150697472) in the 3'-UTR. Therefore, these variants can be used to distinguish between pathogenic and non-pathogenic genomic contexts of the c.955T (p.Gln319) in the genetic diagnosis of congenital adrenal hyperplasia (CAH). The employed methodologies identified a considerable number of individuals with non-pathogenic p.Gln319Ter from the individuals that typically carry the pathogenic p.Gln319Ter in a single CYP21A2. Therefore, it is extremely important the detection of such haplotypes for the prenatal diagnosis, treatment and genetic counseling in patients with CAH.

Familial 5.29 Mb deletion in chromosome Xq22.1–q22.3 with a normal phenotype: a rare pedigree and literature review

BackgroundXq22.1–q22.3 deletion is a rare chromosome aberration. The purpose of this study was to identify the correlation between the phenotype and genotype of chromosome Xq22.1–q22.3 deletions.MethodsChromosome aberrations were identified by copy number variation sequencing (CNV-seq) technology and karyotype analysis. Furthermore, we reviewed patients with Xq22.1–q22.3 deletions or a deletion partially overlapping this region to highlight the rare condition and analyse the genotype–phenotype correlations.ResultsWe described a female foetus who is the “proband” of a Chinese pedigree and carries a heterozygous 5.29 Mb deletion (GRCh37: chrX: 100,460,000–105,740,000) in chromosome Xq22.1–q22.3, which may affect 98 genes from DRP2 to NAP1L4P2. This deletion encompasses 7 known morbid genes: TIMM8A, BTK, GLA, HNRNPH2, GPRASP2, PLP1, and SERPINA7. In addition, the parents have a normal phenotype and are of normal intelligence. The paternal genotype is normal. The mother carries the same deletion in the X chromosome. These results indicate that the foetus inherited this CNV from her mother. Moreover, two more healthy female family members were identified to carry the same CNV deletion through pedigree analysis according to the next-generation sequencing (NGS) results. To our knowledge, this family is the first pedigree to have the largest reported deletion of Xq22.1–q22.3 but to have a normal phenotype with normal intelligence.ConclusionsOur findings further improve the understanding of the genotype–phenotype correlations of chromosome Xq22.1–q22.3 deletions.This report may provide novel information for prenatal diagnosis and genetic counselling for patients who carry similar chromosome abnormalities.

Paternal age, risk of congenital anomalies, and birth outcomes: a population-based cohort study.

The objective of the study was to explore the impact of paternal age on the risk of congenital anomalies and birth outcomes in infants born in the USA between 2016 and 2021. This retrospective cohort study used data from the National Vital Statistics System (NVSS) database, a data set containing information on live birth in the USA between 2016 and 2021. Newborns were divided into four groups based on their paternal age (< 25, 25-34, 35-44, and > 44years) and using the 25-34 age group as a reference. The primary outcomes were congenital anomalies involving structural anomalies and chromosome anomalies. Secondary outcomes were preterm birth, low birth weight, severe neonatal perinatal asphyxia, and admission to neonatal intensive care units (NICU). A multivariable logistic regression model was used to analyze the association between paternal age and outcomes. Overall, 17,764,695 live births were included in the final analyses. After adjusting confounding factors, advanced paternal age > 44years was associated with increased odds of congenital anomalies (adjusted odds ratio (aOR) = 1.17, 95%CI 1.12-1.21) compared with the 25-34 age group, mainly for the chromosomal anomalies (aOR = 1.59, 95%CI 1.40-1.78) but not the structure anomalies (aOR = 1.03, 95%CI 0.97-1.09). The risk of preterm delivery, low birth weight, and NICU hospitalization in their infants was increased by advanced parental age as well. Conclusion: Advanced paternal age increases the risk of congenital anomalies, especially chromosomal anomalies in their offspring, implying prenatal genetic counseling is required. What is Known: • There's a rising trend of advanced paternal age, which is associated with an increased likelihood of premature birth and low birth weight in their offspring. However, the exploration between paternal age and congenital abnormalities in offspring was limitedand contradictory. What is New: • Infants with a paternal age > 44 years were more likely to be born with congenital anomalies, especially chromosomal anomalies.

Prenatal diagnosis and genetic analysis for two Chinese pedigrees carrying large fragment deletions of 13q21

To explore the strategies of prenatal diagnosis and genetic counseling for fetuses of two families with large deletions of 13q21. Two singleton fetuses who were diagnosed with chromosome 13 microdeletions by non-invasive prenatal testing (NIPT) at Ningbo Women and Children's Hospital in March 2021 and December 2021 respectively were selected as the study subjects. Chromosomal karyotyping and chromosomal microarray analysis (CMA) were carried on amniotic samples. Peripheral blood samples were collected from the two couples for CMA assay to determine the origin of abnormal chromosomes identified in the fetuses. The karyotypes of the two fetuses were both normal. CMA revealed that they have respectively harbored heterozygous deletions spanning 11.935 Mb at 13q21.1q21.33 and 10.995 Mb at 13q14.3q21.32, which were respectively inherited from their mother and father. Both deletions had low gene density and lacked haploinsufficient genes, and were predicted to be likely benign variants based on database and literature search. Both couples had opted to continue with the pregnancy. The deletions of the 13q21 region in both families may be of benign variants. As the follow-up time was short, there was no sufficient evidence for the determination of pathogenicity, though our finding may still provide a basis for the prenatal diagnosis and genetic counseling.

A deletion variant Arg616 of androgen receptor in a Chinese family with complete androgen insensitivity syndrome.

Background: Complete androgen insensitivity syndrome (CAIS, OMIM; 300068) is a disorder of sex development with X-linked recessive inheritance. Cases of CAIS usually present as female phenotype, with primary amenorrhea and/or inguinal hernia. Family aggregation is a rare scenario. Methods: This study is a retrospective analysis of CAIS cases in a three-generation pedigree. The patients' genomes were determined by sequencing the androgen receptor (AR) gene. The clinical data of the patients, including manifestations, hormone levels, and AR variants, were analyzed. Results: Sixteen people in this family were involved. A deletion variant (c.1847_1849del; p. Arg616del) was identified in exon 3 of AR, which encodes the DNA binding domain. Until now, four patients and four carriers have been identified in three generations of this family. All the patients live as female, and one has developed gonadal malignancy. Conclusion: The present study identified a deletion variant in three generations of a family with CAIS, including four carriers and four patients. This study verified the genetic pattern and the corresponding clinical characteristics of CAIS. Furthermore, a case with gonadal malignancy was discovered. The information on diagnosis and treatment in this pedigree is useful for prenatal diagnosis and genetic counseling of similar families.

Prenatally detected six duplications at Xp22.33-p11.22: a case report

BackgroundThe discrepancy between the results of cytogenetics and the results of chromosome microarray analysis (CMA) has often led to confusion over genetic counselling for prenatal diagnosis.Case presentationThe prenatal ultrasound results of a congenital heart defect (CHD) foetus displayed an apartial endocardial pad defect and permanently dilated coronary sinus and left superior vena cava at 21 weeks of gestation. Cytogenetic analysis, CMA, fluorescent in situ hybridization (FISH) and multiplex ligation-dependent probe amplification (MLPA) with foetal cord blood samples were used to detect the genetic aetiology. Routine G-binding cytogenetic analysis showed normal karyotypes in both the foetus’ and parents’ blood samples. CMA results demonstrated that there were 53.973-Mb recurrent CNVs at Xp22.33-p11.22, as confirmed by MLPA assay.ConclusionsHerein, we described the CNV of six duplications at Xp22.33-p11.22 and the 53.973 Mb duplication CNV that was not found in foetal cord blood samples by conventional cytogenetic methods, and it was confirmed by CMA and MLPA. Our novel findings will provide helpful information for prenatal diagnosis and genetic counselling for foetal CHDs.

Mode of delivery preference in prenatal genetic counseling between English- and Spanish-speaking patients at two US medical institutions.

Although Hispanic individuals are at an increased risk for various genetic conditions, they have lower uptake of genetic counseling and genetic testing. Virtual appointments have many advantages that may help Spanish-speaking patients access genetic services more readily. Despite these benefits, there are limitations that may make them less attractive options for these individuals. This study aimed to determine if satisfaction with genetic counseling or mode of delivery preference differs between English- and Spanish-speaking individuals who have had a virtual prenatal genetic counseling session. Participants were recruited from prenatal genetic counseling clinics at Indiana University Health and Eskenazi Hospital. A REDCap survey was sent to all eligible participants. Survey questions included mode of delivery preference for future genetic counseling sessions (virtual versus in-person), the validated Genetic Counseling Satisfaction Scale, and questions inquiring about the importance of various factors affecting mode of delivery preference. Spanish-speaking individuals preferred future visits to be in-person, while English-speaking individuals preferred future visits to be virtual (Fisher's exact p = 0.003). Several factors were associated with these preferences, including waiting time, ability to leave/take off work for an appointment, length of session, childcare arrangements, and people attending the appointment (all p < 0.05). Both language groups reported similar mean satisfaction with the genetic counseling provided during their previous virtual appointments (p = 0.51). This study found that certain aspects of virtual genetic counseling appointments make them less appealing to Spanish-speaking individuals. Making virtual genetic counseling appointments more appealing while continuing to offer in-person appointments may help Spanish-speaking individuals receive necessary genetics services. Continued research into disparities and barriers to telemedicine for Spanish-speaking patients is necessary to increase access to this service delivery model for genetic counseling.

Genetic analysis of a Chinese pedigree with 18q21.2-q22.3 duplication and deletion in two offspring respectively resulting from a maternal intrachromosomal insertion

To provide prenatal diagnosis, pedigree analysis and genetic counseling for a pregnant woman who had given birth to a child featuring global developmental delay. A pregnant woman who underwent prenatal diagnosis at the Affiliated Hospital of Southwest Medical University in August 2021 was selected as the study subject. Peripheral blood samples were collected from the woman, her husband and child, in addition with amniotic fluid sample during mid-pregnancy. Genetic variants were detected by G-banded karyotyping analysis and copy number variation sequencing (CNV-seq). Pathogenicity of the variant was predicted based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). Candidate variant was traced in the pedigree to assess the recurrence risk. The karyotypes of the pregnant woman, her fetus, and affected child were 46,XX,ins(18)(p11.2q21q22), 46,X?,rec(18)dup(18)(q21q22)ins(18)(p11.2q21q22)mat and 46,XY,rec(18)del(18)(q21q22)ins(18)(p11.2q21q22)mat, respectively. Her husband was found to have a normal karyotype. CNV-seq has revealed a 19.73 Mb duplication at 18q21.2-q22.3 in the fetus and a 19.77 Mb deletion at 18q21.2-q22.3 in her child. The duplication and deletion fragments were identical to the insertional fragment in the pregnant woman. Based on the ACMG guidelines, the duplication and deletion fragments were both predicted to be pathogenic. The intrachromosomal insertion of 18q21.2-q22.3 carried by the pregnant woman had probably given rise to the 18q21.2-q22.3 duplication and deletion in the two offspring. Above finding has provided a basis for genetic counseling for this pedigree.

Estimation on risk of spontaneous abortions by genomic disorders from a meta-analysis of microarray results on large case series of pregnancy losses.

A meta-analysis on seven large case series (>1000 cases) of chromosome microarray analysis (CMA) on products of conceptions (POC) evaluated the diagnostic yields of genomic disorders and syndromic pathogenic copy number variants (pCNVs) from a collection of 35,130 POC cases. CMA detected chromosomal abnormalities and pCNVs in approximately 50% and 2.5% of cases, respectively. The genomic disorders and syndromic pCNVs accounted for 31% of the detected pCNVs, and their incidences in POC ranged from 1/750 to 1/12,000. The newborn incidences of these genomic disorders and syndromic pCNVs were estimated in a range of 1/4000 to 1/50,000 live births from population genetic studies and diagnostic yields of a large case series of 32,587 pediatric patients. The risk of spontaneous abortion (SAB) for DiGeorge syndrome (DGS), Wolf-Hirschhorn syndrome (WHS), and William-Beuren syndrome (WBS) was 42%, 33%, and 21%, respectively. The estimated overall risk of SAB for major genomic disorders and syndromic pCNVs was approximately 38%, which was significantly lower than the 94% overall risk of SAB for chromosomal abnormalities. Further classification on levels of risk of SAB to high (>75%), intermediate (51%-75%), and low (26%-50%) for known chromosomal abnormalities, genomic disorders, and syndromic pCNVs could provide evidence-based interpretation in prenatal diagnosis and genetic counseling.

Clinical outcomes of fetuses with chromosome 16 short arm copy number variants.

The short arm of chromosome 16 consists of several copy number variants (CNVs) that are crucial in neurodevelopmental disorders; however, incomplete penetrance and diverse phenotypes after birth aggravate the difficulty of prenatal genetic counseling. We screened 15,051 pregnant women who underwent prenatal chromosomal microarray analysis between July 2012 and December 2017. Patients with positive array results were divided into four subgroups based on the type of mutation identified on screening (16p13.3, 16p13.11, 16p12.2, and 16p11.2), and the maternal characteristics, prenatal examinations, and postnatal outcomes of different cases were reviewed. Chromosome 16 CNVs were identified in 34 fetuses, including four with 16p13.3 CNVs, 22 with 16p13.11 CNVs, two with 16p12.2 microdeletions, and six with 16p11.2 CNVs. Of the 34 fetuses, 17 delivered without early childhood neurodevelopmental disorders, three developed neurodevelopmental disorders during childhood, and 10 were terminated. Incomplete penetrance and variable expressivity make prenatal counseling challenging. Most cases with inherited 16p13.11 microduplication were reported to have normal development in early childhood, and we also report a few cases of de novo 16p CNVs without further neurodevelopmental disorders.

Recurrent spontaneous abortion related to balanced translocation of chromosomes – A case report

INTRODUCTION: Recurrent spontaneous abortion (RSA) is defined as three or more consecutive pregnancy losses before the 20th week of gestation. RSA is often idiopathic, but structural chromosomal abnormality is an important cause. An unbalanced karyotype in the conceptus of a couple when one partner has a structural chromosomal abnormality may result in failure to implant, miscarriage, or pregnancy of a fetus with an unbalanced karyotype.CASE PRESENTATION: We report a rare case of RSA associated with balanced translocation of chromosomes. a woman who had four spontaneous abortions, all pregnancy loss happened before 12 weeks of gestation, no other known chronic diseases reported to the family nor medications taken during pregnancy. The karyotype was 46.XX, t(13p,21p) The abnormal karyotype was not found in any other chromosomes. Further spectral karyotyping was performed to rule out the involvement of any other chromosomal aberrations present in the genome.The cytogenetic analysis of the husband revealed a normal karyotype 46.XY.CONCLUSION: Couples with more than three miscarriages should be referred to the genetist for chromosomal analysis for possible hereditary etiology and chromosomal abnormalities responsible for miscarriages to plan prenatal diagnostics and genetic counseling for subsequent pregnancies.

The crucial role of titin in fetal development: recurrent miscarriages and bone, heart and muscle anomalies characterise the severe end of titinopathies spectrum

BackgroundTitin truncating variants (TTNtvs) have been associated with several forms of myopathies and/or cardiomyopathies. In homozygosity or in compound heterozygosity, they cause a wide spectrum of recessive phenotypes with a...

Carrier screening and prenatal diagnosis for thalassemia-associated mutations in Jiaxing area of Zhejiang

To study the molecular epidemiology of thalassemia in Jiaxing area of Zhejiang province and provide a basis for prenatal diagnosis, genetic counseling and prevention and control of birth defects. A total of 24 003 pregnant women who presented at the Jiaxing Maternal and Child Health Care Hospital from April 2017 to September 2021 were enrolled. Capillary hemoglobin electrophoresis in combination with routine blood test were used for primary screening for carriers of thalassemia-associated mutations, and those with positive results were subjected to fluorescence quantitative PCR assay. Prenatal diagnosis was provided for couples with a risk of giving birth to children with intermediate or severe thalassemia. Among the 24 003 pregnant women, 1 211 cases were suspected as carriers of thalassemia-associated mutations, among whom 443 (36.58%) were confirmed by genetic testing. Among these, carriers of α-, β- and α-complex β-globin gene mutations have accounted for 27.31% (121/443), 70.65% (313/443) and 2.04% (9/443), respectively. The result of prenatal diagnosis for an at-risk couple was --SEA/αCSα, and the fetus was predicted to have intermediate or severe thalassemia. Termination of the pregnancy was recommended. Hemoglobin electrophoresis combined with routine blood test during pregnancy may be used as a preliminary screening measure for carriers of thalassemia-associated variants. Combined with genetic testing, this will be of great significance for the control of thalassemia in this region.

A Novel Homozygous Nonsense Variant in the DYM Underlies Dyggve-Melchior-Clausen Syndrome in Large Consanguineous Family.

(1) Background: Dyggve-Melchior-Clausen Syndrome is a skeletal dysplasia caused by a defect in the DYM gene (OMIM number 607461). Pathogenic variants in the gene have been reported to cause Dyggve-Melchior-Clausen (DMC; OMIM 223800) dysplasia and Smith-McCort (SMC; OMIM 607326) dysplasia. (2) Methods: In the present study, large consanguineous families with five affected individuals with osteochondrodysplasia phenotypes were recruited. The family members were analyzed by polymerase chain reaction for homozygosity mapping using highly polymorphic microsatellite markers. Subsequent to linkage analysis, the coding exons and exon intron border of the DYM gene were amplified. The amplified products were then sent for Sanger sequencing. The structural effect of the pathogenic variant was analyzed by different bioinformatics tools. (3) Results: Homozygosity mapping revealed a 9 Mb homozygous region on chromosome 18q21.1 harboring DYM shared by all available affected individuals. Sanger sequencing of the coding exons and exon intron borders of the DYM gene revealed a novel homozygous nonsense variant [DYM (NM_017653.6):c.1205T>A, p.(Leu402Ter)] in affected individuals. All the available unaffected individuals were either heterozygous or wild type for the identified variant. The identified mutation results in loss of protein stability and weekend interactions with other proteins making them pathogenic (4) Conclusions: This is the second nonsense mutation reported in a Pakistani population causing DMC. The study presented would be helpful in prenatal screening, genetic counseling, and carrier testing of other members in the Pakistani community.