Clinical application of SNP array analysis in fetuses with ventricular septal defects and normal karyotypes

Prenatal phenotypes and pregnancy outcomes of fetuses with recurrent 1q21.1 microdeletions and microduplications

Objective

Chromosomal 1q21.1 deletions and duplications are genomic disorders that are usually diagnosed postnatally. However, the genotype-phenotype correlations of 1q21.1 copy number variants (CNVs) during the prenatal period are still not clear. This study aimed to provide a systematic summary of prenatal phenotypes for such genomic disorders.

Methods

In total, 26 prenatal amniotic fluid samples diagnosed with 1q21.1 microdeletions/microduplications were obtained from pregnant women who opted for invasive prenatal testing. Karyotypic analysis and chromosomal microarray analysis (CMA) were performed for all cases simultaneously. The pregnancy outcomes and health conditions after birth in all cases were followed up. Meanwhile, prenatal cases with 1q21.1 microdeletions or microduplications in the literature were retrospectively collected.

Results

In total, 11 pregnancies (11/8,252, 0.13%) with 1q21.1 microdeletions and 15 (15/8,252, 0.18%) with 1q21.1 microduplications were identified. Among these 1q21.1 CNVs, 4 cases covered the thrombocytopenia-absent radius (TAR) region, 16 cases covered the 1q21.1 recurrent microdeletion/microduplication region, and 6 cases covered all regions mentioned above. The prenatal abnormal ultrasound findings were recorded in four participants with 1q21.1 deletions and seven participants with 1q21.1 duplications. Finally, three cases with 1q21.1 deletions and five with 1q21.1 duplications terminated their pregnancies.

Conclusion

In the prenatal setting, 1q21.1 microdeletions were associated with increased nuchal translucency (NT), anomalies of the urinary system, and cardiovascular abnormalities, while 1q21.1 microduplications were correlated with cardiovascular malformations, nasal bone dysplasia, and increased NT. In addition, cerebral ventriculomegaly might be correlated with 1q21.1 microduplications. Considering the variable expressivity and incomplete penetrance of 1q21.1 CNVs, long-term follow-up after birth should be carried out in these cases.

Genetic and ultrasonographic analyses of fetuses with 1q21.1q21.2 microdeletion/microduplication: a retrospective study

BACKGROUND

1q21.1q21.2 microdeletions/microduplications are rare and incompletely penetrant genetic mutations, and only a few reports regarding their prenatal diagnosis are currently available. Here, we analyzed the ultrasonographic phenotypic characteristics of fetuses with these mutations to improve the understanding, diagnosis, and screening of these mutations during gestation.

METHODS

We retrospectively analyzed 8700 cases of pregnant women who underwent invasive prenatal screening by karyotyping and chromosomal microarray analysis (CMA) between November 2016 and November 2021.

RESULTS

CMA revealed copy number changes in the 1q21.1q21.2 region of eleven fetuses, of which five had microdeletions and six had microduplications. These eleven fetuses exhibited variable ultrasonographic phenotypes. Of the five fetuses with the microdeletion, one exhibited a right-dominant heart, permanent right umbilical vein, and mild tricuspid regurgitation, another showed thickened nuchal translucency, and the remaining three had normal ultrasound phenotypes. Two of the six cases with 1q21.1q21.2 microduplication had structural malformations; one of them had a bilateral subependymal cyst, neck mass, and enlarged cardiothoracic ratio, while the other had right ventricular hypoplasia. Of the remaining four cases, two exhibited nasal bone dysplasia, one showed measurement slower than that during menopause and mild tricuspid regurgitation, and another did not show any notable abnormality in ultrasound examination. Among the eleven cases of 1q21.1q21.2 microdeletion/microduplication, only the parents of two fetuses underwent pedigree verification. The parents of these two fetuses with 1q21.1q21.2 microdeletion syndrome chose to continue the pregnancy, and all aspects of postnatal follow-up were normal. The parents of the other nine fetuses refused pedigree verification; of these cases, four cases terminated, and five cases continued the pregnancies. The five continued pregnancies were followed up after birth; no abnormalities were found.

CONCLUSIONS

Fetuses with 1q21.1q21.2 microdeletion/microduplication show different ultrasound characteristics and may have congenital heart disease, thickened nuchal translucency, and nasal bone dysplasia or show no notable abnormalities in an ultrasound examination. Our study highlights that CMA as a powerful diagnostic tool for these diseases can provide an accurate genetic diagnosis, while improving prenatal diagnosis standards.

Congenital Heart Defects and 22q11.2 Deletion Syndrome: A 20-Year Update and New Insights to Aid Clinical Diagnosis

Congenital heart defects (CHDs) are one of the most prevalent clinical features described in individuals diagnosed with 22q11.2 deletion syndrome (22q11.2DS). Therefore, cardiac malformations may be the main finding to refer for syndrome investigation, especially in individuals with a mild phenotype. Nowadays, different cytogenetic methodologies have emerged and are used routinely in research laboratories. Hence, choosing an efficient technology and providing an accurate interpretation of clinical findings is crucial for 22q11.2DS patient's diagnosis. This systematic review provides an update of the last 20 years of research on 22q11.2DS patients with CHD and the investigation process behind each diagnosis. A search was performed in PubMed, Embase, and LILACS using all entry terms to DiGeorge syndrome, CHDs, and cytogenetic analysis. After screening, 60 papers were eligible for review. We present a new insight of ventricular septal defect as a possible pivotal cardiac finding in individuals with 22q11.2DS. Also, we describe molecular technologies and cardiac evaluation as valuable tools in order to guide researchers in future investigations.

Should prenatal chromosomal microarray analysis be offered for isolated ventricular septal defect? A single-center retrospective study from China

Objective

To evaluate the utility of chromosomal microarray analysis (CMA) in fetuses with isolated ventricular septal defect (VSD) and to explore the favorable factors for predicting spontaneous closure of defects.

Methods

The study included 436 singleton pregnancies seen at a referral prenatal diagnosis center, between January 2016 and May 2020, of which 168 fetuses with isolated VSD were diagnosed in the prenatal setting. VSD was classified as an isolated VSD whether it had ultrasound soft markers or not. All patients underwent testing employing quantitative fluorescent polymerase chain reaction (QF-PCR) and CMA as the first-line genetic detection strategies, mainly in amniotic fluid and umbilical blood samples. Rates of chromosomal abnormalities were compared by subgroups of isolated VSD (muscular or perimembranous). Binary logistic regression analysis was performed to predict the independent determinants of spontaneous closure by 2 years.

Results

Overall, the CMA identified clinically significant copy number variations (CNVs) in 7/168 (4.2%) fetuses and variants of unknown significance (VOUS) in 15/168 (8.9%). Muscular and perimembranous VSDs were found in 53.6 and 46.4%, respectively. Clinically significant relevant subchromosomal aberrations were revealed in seven (9.0%) perimembranous VSDs compared with none in 90 muscular defects (P < 0.01). The median initial size of the defect in the muscular VSDs was 2.2(1.8–2.7) mm, as compared to that of 2.8 (2.2–3.2) mm in the perimembranous VSDs group (p = 0.000). In muscular vs. perimembranous VSDs, spontaneous closure occurred more frequently and earlier [40.0 vs. 15.4% in utero (p = 0.000), 61.1 vs. 30.8% at 1-year (p = 0.000), and 75.6 vs. 42.3% at 2-year (P = 0.000)]. Postnatal surgical closure was warranted in 4/90 (4.4%) of the infants with muscular VSDs, as compared to 29/71 (40.8%) with perimembranous defects (p = 0.000). Furthermore, isolated muscular type VSD, smaller defect size, and maternal age of less than 35 years are all positive predictors of spontaneous closure of the defects.

Conclusion

This study highlighted the value of microarray for unbalanced subchromosomal abnormalities in fetuses with isolated VSD, particularly in the perimembranous defects. The detection of an isolated muscular VSD prenatally may be considered a benign or likely benign finding; in contrast, for perimembranous VSD, a prenatal CMA should be offered.

Chromosomal Microarray Analysis in Fetuses Detected with Isolated Cardiovascular Malformation: A Multicenter Study, Systematic Review of the Literature and Meta-Analysis

Cardiovascular malformations (CVM) represent the most common structural anomalies, occurring in 0.7% of live births. The CVM prenatal suspicion should prompt an accurate investigation with fetal echocardiography and the assessment through genetic counseling and testing. In particular, chromosomal microarray analysis (CMA) allows the identification of copy number variations. We performed a systematic review and meta-analysis of the literature, studying the incremental diagnostic yield of CMA in fetal isolated CVM, scoring yields for each category of heart disease, with the aim of guiding genetic counseling and prenatal management. At the same time, we report 59 fetuses with isolated CVM with normal karyotype who underwent CMA. The incremental CMA diagnostic yield in fetuses with isolated CVM was 5.79% (CI 5.54–6.04), with conotruncal malformations showing the higher detection rate (15.93%). The yields for ventricular septal defects and aberrant right subclavian artery were the lowest (2.64% and 0.66%). Other CVM ranged from 4.42% to 6.67%. In the retrospective cohort, the diagnostic yield was consistent with literature data, with an overall CMA diagnostic yield of 3.38%. CMA in the prenatal setting was confirmed as a valuable tool for investigating the causes of fetal cardiovascular malformations.

Analysis of 17 Prenatal Cases with the Chromosomal 1q21.1 Copy Number Variation

Copy number variations (CNVs) at the chromosomal 1q21.1 region represent a group of hot-spot recurrent rearrangements in human genome, which have been detected in hundreds of patients with variable clinical manifestations. Yet, report of such CNVs in prenatal scenario was relatively scattered. In this study, 17 prenatal cases involving the 1q21.1 microdeletion or duplication were recruited. The clinical survey and imaging examination were performed; and genetic detection with karyotyping and CNV analysis using chromosomal microarray (CMA) or CNVseq were subsequently carried out. These cases were all positive with 1q21.1 CNV, yet presented with exceedingly various clinical and utrasonographic indications. Among them, 12 pregnancies carried 1q21.1 deletions, while the other 5 carried 1q21.1 duplications, all of which were within the previously defined breaking point (BP) regions. According to the verification results, 9 CNVs were de novo, 7 were familial, and the other 1 was not certain. We summarized the clinical information of these cases, and the size and distribution of CNVs, and attempted to analyze the association between these two aspects. The findings in our study may provide important basis for the prenatal diagnosis and genetic counseling on such conditions in the future.

Dextro-transposition of the great arteries in one twin: case reports and literature review

BACKGROUND

Dextro-transposition of the great arteries (D-TGA) is a rare congenital heart disease, as it affects only 0.02-0.05% of live births. It is the second most common cyanotic heart disease following Tetralogy of Fallot. It has a male predominance. Fetal echocardiography is an optimal method for prenatal diagnosis of fetal D-TGA. In twin pregnancies, fetal D-TGA in one twin is very rare, especially in monochorionic-diamniotic twin pregnancies. Herein, we report a case of D-TGA in one twin in two dichorionic-diamniotic twin pregnancies and one monochorionic-diamniotic twin pregnancy from January 2018 to June 2021.

CASE DESCRIPTION

One twin with D-TGA was diagnosed by fetal echocardiography in the second trimester, and the co-twin was normal in all three cases. A multidisciplinary team provided extensive counseling regarding the D-TGA twin and the co-twin, and adequate perinatal management was provided. In cases 1, 2, and 3, the mothers underwent cesarean sections at 37 weeks + 2 days, 34 weeks + 5 days, and 36 weeks + 1 day, respectively. In case 1, which involved a female D-TGA neonate with birth weight 2,410 g, an emergent atrial septostomy was performed at 20 h after birth, and the neonate underwent atrial switch operation (ASO) 24 days after birth. In case 2, involving a male D-TGA neonate with a birth weight of 2,380 g, ASO was performed 24 days after birth. In case 3, involving a female D-TGA neonate with birth weight 2,240 g, ASO was performed 19 days after birth and delayed sternal closure was performed 4 days later. All six infants showed normal development during follow-up.

CONCLUSIONS

Early antenatal diagnosis of D-TGA in one fetus of a twin pregnancy is significantly important. A multidisciplinary team should carry individual evaluation and integrated management of the D-TGA twin and co-twin during the pregnancy and perinatal period. After birth, delayed ductus arteriosus closure in the D-TGA twins should be performed when necessary and individualized timings for arterial switch operation should be considered.

Prenatally diagnosed isolated perimembranous ventricular septal defect: genetic and clinical implications

Objective

To evaluate the incidence of chromosomal aberrations and the clinical outcomes following the prenatal diagnosis of isolated perimembranous ventricular septal defect (pVSD).

Methods

This retrospective study was composed of a cohort of pregnant women whose fetuses were diagnosed with isolated pVSD. Complete examinations of the fetal heart were performed, as well as a postnatal validation echocardiography follow‐up at 1 year of age. The collected data included: spontaneous closure of the pVSD, need for intervention, chromosomal aberrations and postnatal outcome.

Results

Fifty‐five pregnant women were included in the study. 34/55 (61.8%) of the fetuses underwent prenatal genetic workup which revealed no abnormal results. No dysmorphic features or abnormal neurological findings were detected postnatally in those who declined a prenatal genetic workup during the follow‐up period of 2 years. In 25/55 of the cases (45.4%), the ventricular septal defects (VSD) closed spontaneously in utero, whereas in 17 cases of this group (30.9%) the VSD closed during the first year of life. None of the large 3 VSDs cases (>3 mm), closed spontaneously.

Conclusion

Prenatally isolated perimembranous VSD has a favorable clinical outcome when classified as small‐to‐moderate size, children in our cohort born with such findings had no macroscopic chromosomal abnormalities.

What's already known about this topic?

The detection rates of perimembranous ventricular septal defect (PVSD) is improving in recent years.

What does this study add?

We found no evidence that isolated pVSD is a significant risk factor for chromosomal anomalies.

Isolated small and medium size (<3 mm) PVSD's have a favorable clinical outcome with resolution either prenatally or within the infant's first year of life.

Molecular Approaches in Fetal Malformations, Dynamic Anomalies and Soft Markers: Diagnostic Rates and Challenges-Systematic Review of the Literature and Meta-Analysis

Fetal malformations occur in 2-3% of pregnancies. They require invasive procedures for cytogenetics and molecular testing. "Structural anomalies" include non-transient anatomic alterations. "Soft markers" are often transient minor ultrasound findings. Anomalies not fitting these definitions are categorized as "dynamic". This meta-analysis aims to evaluate the diagnostic yield and the rates of variants of uncertain significance (VUSs) in fetuses undergoing molecular testing (chromosomal microarray (CMA), exome sequencing (ES), genome sequencing (WGS)) due to ultrasound findings. The CMA diagnostic yield was 2.15% in single soft markers (vs. 0.79% baseline risk), 3.44% in multiple soft markers, 3.66% in single structural anomalies and 8.57% in multiple structural anomalies. Rates for specific subcategories vary significantly. ES showed a diagnostic rate of 19.47%, reaching 27.47% in multiple structural anomalies. WGS data did not allow meta-analysis. In fetal structural anomalies, CMA is a first-tier test, but should be integrated with karyotype and parental segregations. In this class of fetuses, ES presents a very high incremental yield, with a significant VUSs burden, so we encourage its use in selected cases. Soft markers present heterogeneous CMA results from each other, some of them with risks comparable to structural anomalies, and would benefit from molecular analysis. The diagnostic rate of multiple soft markers poses a solid indication to CMA.

Heterozygous NOTCH1 deletion associated with variable congenital heart defects

Pathogenic heterozygous variants in the NOTCH1 gene are known to be associated with both left and right-sided congenital cardiac anomalies with strikingly incomplete penetrance and variable phenotypic expressivity. De novo NOTCH1 whole gene deletion has been reported rarely in the literature and its association with cardiac defects is less well established. Here, we report four cases of NOTCH1 gene deletion from two families associated with a spectrum of congenital heart defects from bicuspid aortic valve to complex cardiac anomalies. This is the first description of a familial NOTCH1 deletion, showing apparently high penetrance, which may be unique to this mechanism of disease. Immunohistochemical staining of cardiac tissue demonstrated reduced levels of NOTCH1 expression in both the left and right ventricular outflow tracts. These cases suggest that haploinsufficiency caused by NOTCH1 gene deletion is associated with both mild and severe cardiac defects, similar to those caused by pathogenic variants in the gene, but with apparently higher, if not complete, penetrance.

The effect of polyhydramnios degree on chromosomal microarray results: a retrospective cohort analysis of 742 singleton pregnancies

PURPOSE

To analyze the risk for clinically significant microarray aberrations in pregnancies with polyhydramnios.

METHODS

Data from all chromosomal microarray analyses (CMA) performed due to polyhydramnios between January 2013 and December 2019 were retrospectively obtained from the Ministry of Health Database. The rate of clinically significant (pathogenic and likely pathogenic) CMA findings in isolated and non-isolated polyhydramnios cohorts was compared to a local control group of 5541 fetuses with normal ultrasound, in which 78 (1.4%) abnormal results were demonstrated. Subgroup analyses were performed by the degree of polyhydramnios, week of diagnosis, maternal age, and the presence of additional sonographic anomalies.

RESULTS

In the isolated polyhydramnios cohort, 19/623 (3.1%) clinically significant CMA aberrations were noted, a significantly higher rate compared to the control population. However, the risk for abnormal CMA results in the 158 cases with mild polyhydramnios (AFI 25-29.9, or maximal vertical pocket 8-11.9 cm) did not significantly differ from pregnancies with normal ultrasound. Of 119 cases of non-isolated polyhydramnios (most frequently associated with cardiovascular (26.1%) and brain (15.1%) anomalies), 8 (6.7%) abnormal CMA findings were noted, mainly karyotype-detectable.

CONCLUSION

Mild polyhydramnios was not associated with an increased rate of clinically significant microarray results, compared to pregnancies with normal ultrasound. An extensive anatomical sonographic survey should be performed in pregnancies with polyhydramnios, with consideration of fetal echocardiography.

Microarray analysis in fetuses with duodenal obstruction: It is not just trisomy 21

OBJECTIVE

To explore the copy number variants (CNVs) in case of fetal duodenal obstruction (DO) and assess the associated prenatal findings and postnatal outcomes.

MATERIALS AND METHODS

This retrospective study reviewed 51 fetuses with DO and the findings of chromosomal microarray analysis (CMA) used as a first-tier test in our institution between January 2014 and May 2019.

RESULTS

The frequency of pathogenic aberrations in fetuses with DO was 15.7% (8/51), including 9.8% (5/51) pathogenic CNVs. Three fetuses with isolated DO each had a deletion on chromosome 13q, one fetus had duplication at 1q43q44, and one had microduplication at 17q12. No significant differences in pathogenic CNVs were observed between isolated DO and DO plus additional anomalies (4/42, 9.5% vs 1/9, 11.1%, P = .89). Of the 51 fetuses with DO, 11 pregnancies were terminated, and eight fetuses had chromosomal abnormalities; one pregnancy ended with intrauterine death, and there were 39 live births. Neonatal outcomes were available for 31 fetuses, and no neonatal deaths occurred after surgery.

CONCLUSIONS

Our cohort study demonstrated the value of CMA in fetuses with DO, suggesting that CNVs may underly genetic etiologies that should be considered in the diagnostic evaluation of DO. We think CMA should be recommended in case of DO.

Prenatally detected isolated ventricular septum defects and the association with chromosomal aberrations-A nationwide register-based study from Denmark

OBJECTIVE

To evaluate the association between prenatally detected isolated ventricular septum defects (VSDs) and chromosomal aberrations in a nationwide study in Denmark.

METHOD

Nationwide, register-based study with prospectively collected data including all singleton pregnancies from 2014-2018. From the Danish Fetal Medicine Database, we retrieved data on maternal characteristics, first-trimester biomarkers, pre- and postnatal diagnoses, genetic test results, and pregnancy outcomes. VSDs were considered isolated in the absence of other malformations or soft markers, and with a low first-trimester risk assessment for trisomies 21, 18 and 13. All cases of an isolated VSD with a chromosomal anomaly were audited. The genetic tests included karyotyping and chromosomal microarray.

RESULTS

We retrieved data on 292 108 singleton pregnancies; 323 registered with a prenatally detected VSD and 697 with a VSD detected postnatally (incidence of 0.35%). Only 1/153 (0.7%, 95% CI 0.02;3.6%) of the isolated prenatally detected VSDs had an abnormal genetic test result (del (8)(q23.1)). Moreover, they had a lower free β-hCG MoM (0.9 MoM vs 0.99 MoM, P = 0.02), and were more likely born small for gestational age (SGA), defined as birthweight 2 or more SD below the mean, compared with the control population (5.2% vs 2.5%, P = 0.03).

CONCLUSION

We found a prevalence of chromosomal aberrations of 0.7% in fetuses with a prenatally detected isolated VSD. Moreover, we found an association between isolated VSDs and a larger proportion being born SGA.

What have we learned from 691 prenatal chromosomal microarrays for ventricular septal defects?

INTRODUCTION

Ventricular septal defect (VSD) represents the most common type of congenital cardiac anomaly, affecting more than 1 in 300 live births. The objective of this study was to examine the incidence and nature of abnormal chromosomal microarray analysis (CMA) results in a large cohort of pregnancies with VSD.

MATERIAL AND METHODS

Data acquisition was performed through the Ministry of Health computerized database. All CMA results performed due to VSD during 2013-2017 were included. The rates of clinically significant CMA results of cases with isolated and non-isolated VSD were compared with two control populations-a systematic review of 9272 pregnancies and a local cohort of 5541 fetuses with normal ultrasound.

RESULTS

Overall, 691 CMA analyses performed due to a sonographic indication of VSD were detected. Of 568 pregnancies with isolated VSD, eight (1.4%) clinically significant copy number variants were detected, a nonsignificant difference compared with low risk pregnancies. Of the 123 pregnancies with non-isolated VSDs, 18 (14.6%) clinically significant CMA results were detected, a considerably increased risk compared with control pregnancies. Karyotype-detectable anomalies constituted 12 of the 18 abnormal CMA results in non-isolated VSD group (66.7%), a significantly higher proportion compared with 2 of 8 (25%) in isolated VSD cohort.

CONCLUSIONS

The outcomes of our study, representing the largest number of CMA results in pregnancies with VSD, suggest that the rate of abnormal CMA findings in isolated VSD does not differ from pregnancies with normal ultrasound. This observation is true for populations undergoing routine common trisomy screening tests and early sonographic evaluation, as well as widely available non-invasive prenatal screening. Conversely, CMA analysis yields a high detection rate in pregnancies with non-isolated VSD. Our results question the recommendation to perform invasive prenatal testing for CMA in pregnancies with isolated VSD.

[Genetic analysis of a fetus with multiple malformations caused by complex translocations of four chromosomes]

OBJECTIVE

To conduct genetic analysis in a fetus with complex translocation of four chromosomes.

METHODS

G-banded chromosome karyotype analysis, single nucleotide polymorphism array (SNP array) and fluorescence in situ hybridization (FISH) were performed in a fetus with multiple malformations. Peripheral blood chromosome karyotype and FISH were also carried out for the parents.

RESULTS

The fetal amniotic fluid karyotype was 46, XY, t(12; 13)(q22; q32). SNP array analysis showed that there were 20 192 kb duplication at 1q42.13q44 and 13 293 kb deletion at 15q26.1q26.3 in the fetus. The results of karyotype and SNP array were inconsistent. FISH analyses on the parental peripheral blood samples demonstrated that the mother was a cryptic 46, XX, t(1; 15)(q42.1; q26.1) translocation. The fetus had inherited 46, XY, t(12; 13)(q22; q32) from his father and der(15)t(1; 15)(q42.1; q26.1) from his mother.

CONCLUSIONS

The 1q42.13q44 duplication and 15q26.1q26.3 deletion may have contributed to the abnormal sonographic features of the fetus. The combination of cytogenetic, SNP array and FISH techniques was beneficial for providing an accurate genetic counseling.

Identification of Novel Regulatory Genes in APAP Induced Hepatocyte Toxicity by a Genome-Wide CRISPR-Cas9 Screen

Acetaminophen (APAP) is a commonly used analgesic responsible for more than half of acute liver failure cases. Identification of previously unknown genetic risk factors would provide mechanistic insights and novel therapeutic targets for APAP-induced liver injury. This study used a genome-wide CRISPR-Cas9 screen to evaluate genes that are protective against, or cause susceptibility to, APAP-induced liver injury. HuH7 human hepatocellular carcinoma cells containing CRISPR-Cas9 gene knockouts were treated with 15 mM APAP for 30 minutes to 4 days. A gene expression profile was developed based on the 1) top screening hits, 2) overlap of expression data from APAP overdose studies, and 3) predicted affected biological pathways. We further demonstrated the implementation of intermediate time points for the identification of early and late response genes. This study illustrated the power of a genome-wide CRISPR-Cas9 screen to systematically identify novel genes involved in APAP-induced hepatotoxicity and to provide potential targets to develop novel therapeutic modalities.

Clinical value of chromosomal microarray analysis in prenatally diagnosed dextro-transposition of the great arteries

Objectives: To evaluate the usefulness of chromosomal microarray analysis (CMA) in fetuses with dextro-transposition of the great arteries (d-TGA).Methods: Thirty-two fetuses with d-TGA were examined for submicroscopic copy number variations (CNVs) using CMA.Results: Among the 32 d-TGA fetuses, 23 had isolated lesions (71.9%) and nine had other cardiac or extracardiac anomalies (28.1%). CNVs were detected in 16/32 (50%) of the fetuses, including benign CNVs detected in nine fetuses (28.1%), pathogenic CNVs detected in three fetuses (9.4%), and variants of unknown significance (VOUS) detected in four fetuses (12.5%). There was no significant difference in the detection rates of pathogenic CNVs between the isolated and nonisolated groups. All four VOUS were found in the nonisolated group.Conclusion: CMA might be an effective tool for identifying submicroscopic chromosomal aberrations in fetuses with d-TGA.

Polymorphisms/Mutations in A-Kinase Anchoring Proteins (AKAPs): Role in the Cardiovascular System

A-kinase anchoring proteins (AKAPs) belong to a family of scaffolding proteins that bind to protein kinase A (PKA) by definition and a variety of crucial proteins, including kinases, phosphatases, and phosphodiesterases. By scaffolding these proteins together, AKAPs build a "signalosome" at specific subcellular locations and compartmentalize PKA signaling. Thus, AKAPs are important for signal transduction after upstream activation of receptors ensuring accuracy and precision of intracellular PKA-dependent signaling pathways. Since their discovery in the 1980s, AKAPs have been studied extensively in the heart and have been proven essential in mediating cyclic adenosine monophosphate (cAMP)-PKA signaling. Although expression of AKAPs in the heart is very low, cardiac-specific knock-outs of several AKAPs have a noteworthy cardiac phenotype. Moreover, single nucleotide polymorphisms and genetic mutations in crucial cardiac proteins play a substantial role in the pathophysiology of cardiovascular diseases (CVDs). Despite the significant role of AKAPs in the cardiovascular system, a limited amount of research has focused on the role of genetic polymorphisms and/or mutations in AKAPs in increasing the risk of CVDs. This review attempts to overview the available literature on the polymorphisms/mutations in AKAPs and their effects on human health with a special focus on CVDs.