The Consequences of Abnormal Gene Dosage: Lessons from Chromosome 18.

Accurate interpretation of genomic copy number variation (CNV) remains a challenge and has important consequences for both congenital and late-onset disease. Hemizygosity dosage characterization of the genes on chromosome 18 reveals a spectrum of outcomes ranging from no clinical effect, to risk factors for disease, to both low- and high-penetrance disease. These data are important for accurate and predictive clinical management. Additionally, the potential mechanisms of reduced penetrance due to dosage compensation are discussed as a key to understanding avenues for potential treatment. This review describes the chromosome 18 findings, and discusses the molecular mechanisms that allow haploinsufficiency, reduced penetrance, and dosage compensation.

Prevalence and descriptive epidemiology of Turner syndrome in the United States, 2000-2017: A report from the National Birth Defects Prevention Network.

The lack of United States population-based data on Turner syndrome limits assessments of prevalence and associated characteristics for this sex chromosome abnormality. Therefore, we collated 2000-2017 data from seven birth defects surveillance programs within the National Birth Defects Prevention Network. We estimated the prevalence of karyotype-confirmed Turner syndrome diagnosed within the first year of life. We also calculated the proportion of cases with commonly ascertained birth defects, assessed associations with maternal and infant characteristics using prevalence ratios (PR) with 95% confidence intervals (CI), and estimated survival probability. The prevalence of Turner syndrome of any pregnancy outcome was 3.2 per 10,000 female live births (95% CI = 3.0-3.3, program range: 1.0-10.4), and 1.9 for live birth and stillbirth (≥20 weeks gestation) cases (95% CI = 1.8-2.1, program range: 0.2-3.9). Prevalence was lowest among cases born to non-Hispanic Black women compared to non-Hispanic White women (PR = 0.5, 95% CI = 0.4-0.6). Coarctation of the aorta was the most common defect (11.6% of cases), and across the cohort, individuals without hypoplastic left heart had a five-year survival probability of 94.6%. The findings from this population-based study may inform surveillance practices, prenatal counseling, and diagnosis. We also identified racial and ethnic disparities in prevalence, an observation that warrants further investigation.

In vitro cytogenotoxic evaluation of aripiprazole on human peripheral lymphocytes and computational molecular docking analysis.

Two different drug groups, typical (classic) and atypical (new), are used in the treatment of schizophrenia. Aripiprazole, an atypical antipsychotic chemical, is the active ingredient of the drug Abilify. This study was conducted to determine the possible genotoxic effect of aripiprazole. For this purpose, four different doses of aripiprazole (5; 10; 20, and 40 µg/mL) were examined with Chromosome Abnormality (CA), Sister Chromatid Exchange (SCE), Micronucleus (MN) tests. Based on these tests, Proliferation Index (PI), Percent Abnormal Cells (AC), Mitotic Index (MI), Micronuclear Binuclear Cell (MNBN), and Nuclear Division Index (NDI) levels were determined in human peripheral lymphocytes treated for 24 and 48 hours. Also, to determine possible binding sites of Aripiprazole on B-DNA molecular docking analysis was performed using AutoDock 4.0 (B-DNA dodecamer, PDB code: 1BNA). Aripiprazole binds to B-DNA with a very significant free binding energy (-11.88 Kcal/mol). According to our study, aripiprazole did not significantly change SCE, CA, AC percentage, MN frequencies when compared with control. According to these results, aripiprazole does not have a genotoxic effect. At the same time, no significant change was observed in the PI, MI, and NDI frequencies when compared with the control. In line with these results, it was observed that the use of aripiprazole in the treatment of schizophrenia did not pose any acute genotoxic and cytotoxic risk.

Recurrent pregnancy loss: fewer chromosomal abnormalities in products of conception? a meta-analysis.

OBJECTIVE: To compare the prevalence of chromosomal abnormalities detected in products of conception (POCs) between recurrent pregnancy loss and sporadic pregnancy loss. METHODS: A systematic search was performed in the PubMed and Embase databases from inception to December 31, 2020. Relevant studies analysing the association between the number of pregnancy losses and the incidence of chromosomal abnormalities were included. Independent data extraction was conducted and study quality was assessed. Meta-analyses were carried out to calculate odds ratios by using fixed- or random-effects models according to statistical homogeneity. RESULTS: A total of 8320 POCs in 19 studies were identified for the meta-analyses. The incidence of chromosomal abnormalities in sporadic pregnancy loss was significantly higher than that in recurrent pregnancy loss. In subgroup analyses, the following studies reported a high incidence of abnormal outcomes of sporadic pregnancy loss: studies with ≥ 300 samples, studies published before 2014, studies conducted in European and American countries, and studies with analyses using conventional karyotype techniques. Moreover, the incidence of chromosomal abnormalities in women with two pregnancy losses was significantly higher than that in women with three or more pregnancy losses. However, there was no difference in the distribution of abnormal types between sporadic and recurrent pregnancy loss or between two and three or more pregnancy losses. CONCLUSIONS: The prevalence of chromosomal abnormalities detected in POCs was lower in recurrent pregnancy loss than in sporadic pregnancy loss, and decreased with an increasing number of pregnancy losses.

Complementary Approaches in Fetal Genetic Diagnosis: Decision-Making Process and Alternative Choices for Clinicians in a Secondary Health Care Institution.

OBJECTIVES: The aim of this study was to determine indications of invasive, genetic results of conventional karyotyping and chromosomal microarray analysis and culture failure rates to discuss possible solution options and guide our clinical choices. MATERIALS AND METHODS: Fetal samples were analyzed by conventional karyotyping, array comparative genomic hybridization, fluorescence in situ hybridization. RESULTS: Failure rates of chorionic villus sampling (CVS) and amniocentesis were as follows, respectively: 4.5% and 0.4%. The rates of abnormal genetic results in fetuses with only thickened nuchal translucency and thickened nuchal translucency + USG abnormality were %4.2 and %40, respectively. CONCLUSIONS: Abnormal genetic results showed a significant increase in cases of thickened nuchal translucency accompanied by USG abnormalities. Although culture failure rates in the CVS were higher, none of the cases remained inconclusive. Centers with prenatal invasive genetic diagnosis should offer a wide spectrum of genetic tests by medical genetics specialists.

Prenatal ultrasound diagnosis of Klippel-Trenaunay-Weber syndrome associated with umbilical cord hemangioma.

We describe a case of prenatal diagnosed Klippel-Trenaunay-Weber syndrome, which mainly manifested as hypertrophy of the left thigh, and was associated with umbilical cord hemangioma and loss of heterozygosity (LOH) for 1q21.2 q44. This case report describes the second reported case associated with umbilical cord hemangioma and the first reported case with LOH for 1q21.2 q44.

Confirmatory testing illustrates additional risks for structural sex chromosome abnormalities in fetuses with a non-invasive prenatal screen positive for monosomy X.

More and more women rely on non-invasive prenatal screening (NIPS) to detect fetal sex and risk for aneuploidy. The testing applies massively parallel sequencing or single nucleotide polymorphism (SNP) microarray to circulating cell-free DNA to determine relative copy number. In addition to trisomies 13, 18, and 21, some labs offer screening for sex chromosome abnormalities as part of their test. In this study, an index neonate screened positive for monosomy X and had discordant postnatal chromosomes indicating an X;autosome translocation. This patient prompted a retrospective chart review for similar cases at a large NIPS testing center. The review found 28 patients with an abnormal NIPS for monosomy X who were eventually diagnosed with additional discrepant structural sex chromosome abnormalities including translocations, isochromosomes, deletions, rings, markers, and uniparental disomy. The majority of these were mosaic with monosomy X, but in seven cases, there was no evidence of mosaicism on confirmatory testing. The identification of multiple sex chromosome aneuploidies in these cases supports the need for additional genetic counseling prior to NIPS testing and following abnormal NIPS results that are positive for monosomy X. This finding broadens our knowledge about the variable outcomes of positive monosomy X NIPS results and emphasizes the importance of confirmatory testing and clinical follow up for these patients.

PGT-A preimplantation genetic testing for aneuploidies and embryo selection in routine ART cycles: Time to step back?

Embryo aneuploidies may be responsible for implantation failures, miscarriages and affects IVF outcomes. A variety of technologies have been implemented to individuate euploid embryos in IVF treatments, which is named preimplantation genetic testing for aneuploidies (PGT-A). According to this strategy, a better embryo selection should increase IVF results. In reality, several issues remain unaddressed including the sampling strategy, involving the test outcomes, and the frequent occurrence of embryo mosaicism, affecting the criteria for selection of supposed viable embryos and possibly posing an ethical dilemma. Safety issues are in place, including perinatal and postnatal consequences of embryo sampling and the epigenetic weaknesses from a prolonged in vitro culture, necessary for trophectoderm biopsy. On the other side, chromosome number mistakes are progressively recognized as physiologic events in the early pre-implantation embryo with many corrective mechanisms in place and their destiny in the post-implantation development is unclear. Accordingly, the increasing precision of the diagnostic tools should be used to investigate the effect of such interventions within rigorous research programs in the sake of improved clinical outcomes. Meantime the diagnosis of embryo aneuploidies in IVF cycles should be considered as a research tool and systematic implementation in clinical practice may appear unjustified.

Microarray and RASopathy-disorder testing in fetuses with increased nuchal translucency.

OBJECTIVES: To determine the incidence of chromosomal abnormalities, submicroscopic chromosomal abnormalities and RASopathy-disorder (RD) pathogenic variants in a cohort of pregnancies with nuchal translucency thickness (NT) ≥ 3.5 mm, and to propose a clinical protocol for surveillance of this group of patients. METHODS: This was a retrospective chart review of patients referred to The Prenatal Diagnosis and Medical Genetics Program at Mount Sinai Hospital between January 2013 and December 2015, due to NT ≥ 3.5 mm, who underwent chorionic villus sampling or amniocentesis. Patients underwent extensive genetic counseling prior to invasive procedures and testing. Quantitative fluorescence polymerase chain reaction (QF-PCR) was performed as the first-line test for aneuploidy. If the result was negative, patients underwent karyotyping and/or chromosomal microarray analysis (CMA), and if the findings were normal, they had testing for RD pathogenic variants, which included nine known genes. Patients also underwent detailed fetal ultrasound examinations and echocardiography, performed by expert operators. RESULTS: A total of 226 eligible patients were identified. In 116/226 (51.3%) patients, QF-PCR identified a chromosomal aneuploidy. The remaining 110/226 (48.7%) patients had further genetic testing. Karyotyping/CMA detected an abnormal/pathogenic cytogenetic result in 9/110 (8.2%) patients, as well as five variants of unknown significance (VOUS). RD testing yielded three pathogenic variants (3/103), giving a detection rate of 2.9%, and one VOUS. The optimal NT cut-off for RD screening was 7.9 mm in this population. In 92/110 (83.6%) patients, the genetic investigations were normal. Of these pregnancies, an early (14-16 weeks' gestation) detailed fetal ultrasound examination identified a structural abnormality in 24 (26.1%), 15 (16.3%) had an abnormal detailed ultrasound examination at 18-22 weeks' gestation and fetal echocardiography showed a cardiac abnormality in nine (9.8%). The birth outcome in the 83 pregnancies that had normal genetic investigations and known outcome included seven (8.4%) cases of termination of pregnancy, seven (8.4%) cases of intrauterine fetal death and 69 (83.1%) cases of live birth. Nine (9.8%) patients were lost to follow-up. CONCLUSIONS: Both CMA and molecular testing for RD are important investigations in pregnancies with NT ≥ 3.5 mm. The use of genetic testing combined with fetal ultrasound examination provides valuable information that can influence pregnancy outcome, and provide recurrence risks, in this patient population. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

State-wide utilization and performance of traditional and cell-free DNA-based prenatal testing pathways: the Victorian Perinatal Record Linkage (PeRL) study.

OBJECTIVES: To perform individual record linkage of women undergoing screening with cell-free DNA (cfDNA), combined first-trimester screening (CFTS), second-trimester serum screening (STSS), and/or prenatal and postnatal cytogenetic testing with the aim to (1) obtain population-based estimates of utilization of prenatal screening and invasive diagnosis, (2) analyze the performance of different prenatal screening strategies, and (3) report the residual risk of any major chromosomal abnormality following a low-risk aneuploidy screening result. METHODS: This was a retrospective study of women residing in the state of Victoria, Australia, who underwent prenatal screening or invasive prenatal diagnosis in 2015. Patient-funded cfDNA referrals from multiple providers were merged with state-wide results for government-subsidized CFTS, STSS and invasive diagnostic procedures. Postnatal cytogenetic results from products of conception and infants up to 12 months of age were obtained to ascertain cases of false-negative screening results and atypical chromosomal abnormalities. Individual record linkage was performed using LinkageWizTM . RESULTS: During the study period, there were 79 140 births and 66 166 (83.6%) women underwent at least one form of aneuploidy screening. Linkage data were complete for 93.5% (n = 61 877) of women who underwent screening, and of these, 73.2% (n = 45 275) had CFTS alone, 20.2% (n = 12 486) had cfDNA alone; 5.3% (n = 3268) had STSS alone, 1.3% (n = 813) had both CFTS and cfDNA, and < 0.1% (n = 35) had both STSS and cfDNA. CFTS had a combined sensitivity for trisomies 21 (T21), 18 (T18) and 13 (T13) of 89.57% (95% CI, 82.64-93.93%) for a screen-positive rate (SPR) of 2.94%. There were 12 false-negative results in the CFTS pathway, comprising 10 cases of T21, one of T18 and one of T13. cfDNA had a combined sensitivity for T21, T18 and T13 of 100% (95% CI, 95.00-100%) for a SPR of 1.21%. When high-risk cfDNA results for any chromosome (including the sex chromosomes) and failed cfDNA tests were treated as screen positives, the SPR for cfDNA increased to 2.42%. The risk of any major chromosomal abnormality (including atypical abnormalities) detected on prenatal or postnatal diagnostic testing after a low-risk screening result was 1 in 1188 for CFTS (n = 37) and 1 in 762 for cfDNA (n = 16) (P = 0.13). The range of chromosomal abnormalities detected after a low-risk cfDNA result included pathogenic copy-number variants (n = 6), triploidy (n = 3), rare autosomal trisomies (n = 3) and monosomy X (n = 2). CONCLUSIONS: Our state-wide record-linkage analysis delineated the utilization and clinical performance of the multitude of prenatal screening pathways available to pregnant women. The sensitivity of cfDNA for T21, T18 and T13 was clearly superior to that of CFTS. While there was no statistically significant difference in the residual risk of any major chromosomal abnormality after a low-risk CFTS or cfDNA result, there were fewer live infants diagnosed with a major chromosomal abnormality in the cfDNA cohort. These data provide valuable population-based evidence to inform practice recommendations and health policies. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Pedigree analysis of two brothers with severe oligozoospermia caused by maternal inv(X) (p22.3, q22) chromosome abnormality.

Sex chromosome abnormality (SCA) is one of the major causes of male spermatogenesis dysfunction. In our study, we sought to investigate the novel X chromosome inversion leading to severe oligozoospermia. Here, we report two brothers with severe oligozoospermia without any other abnormal clinical phenotype. The chromosome karyotypes in peripheral blood of both brothers were 46, Y, inv (X) (p22.3, q22), and no Y chromosome microdeletion was found. The karyotype of their mother was 46, X, inv (X) (p22.3, q22) and that of their father was 46, XY. This is the first report in China that X chromosomal inversion, 46, Y, inv (X) (p22.3, q22), is associated with severe oligozoospermia. This inversion may be a direct genetic risk factor for spermatogenesis.

[48,XXYY syndrome: A report of four cases].

OBJECTIVE: To explore the clinical characteristics and prognosis of the 48,XXYY syndrome and gain a deeper insight into this condition. METHODS: This retrospective study included 4 cases of 48,XXYY syndrome confirmed between 2011 and 2018. We analyzed the general information, clinical manifestations, laboratory results, imaging features and outcomes of assisted reproductive technology (ART) of the patients and reviewed the relevant literature. RESULTS: The 4 patients with 48,XXYY syndrome were characterized by low literacy, soft texture and small volume of the testis, high levels of FSH and LH, and low level of serum T. Two of them were diagnosed with ejaculatory dysfunction and aspermia, and the other 2 with normal ejaculatory function but azoospermia. Biochemical analysis of seminal plasma indicated normal quantifications of both fructose and neutral α glucosidase. ART with donor sperm was performed for all the 4 cases and 3 of them got full-term babies. CONCLUSIONS: The 48,XXYY syndrome is often complicated by hypergonadotropic hypogonadism, with the clinical manifestations of aspermia or non-obstructive azoospermia. ART with donor sperm can be employed to help the patient with 48,XXYY syndrome get their non-biological offspring.

"Donating our bodies to science": A discussion about autopsy and organ donation in Turner syndrome.

At the Third Turner Resource Network Symposium, a working group presented the results of collaborative discussions about the importance of autopsy in Turner syndrome (TS). Considerable gaps in understanding the causes of death in TS can only be closed by more frequent death investigations and autopsies. The presentation included an overview of autopsy methods, strategies for utilizing autopsy, and biobanking to address research questions about TS, and the role of palliative care in the context of autopsy. This review highlights strategies to promote autopsy and tissue donation, culminating with an action plan to increase autopsy rates in the TS community.

Comorbidity landscape of the Danish patient population affected by chromosome abnormalities.

PURPOSE: Most chromosome abnormality patients require long-term clinical care. Awareness of mosaicism and comorbidities can potentially guide such health care. Here we present a population-wide analysis of direct and inverse comorbidities affecting patients with chromosome abnormalities. METHODS: We extracted direct and inverse comorbidities for the 11 most prevalent chromosome abnormalities from the Danish National Patient Registry (covering 6.9 million patients hospitalized between 1994 and 2015): trisomy 13, 18, and 21, Klinefelter (47,XXY), triple X, XYY, Turner (45,X), Wolf-Hirschhorn, Cri-du-chat, Angelman, and Fragile X syndromes (FXS). We also performed four sub-analyses for male/female Down syndrome (DS) and FXS and non-mosaic/mosaic DS and Turner syndrome. RESULTS: Our data cover 9,003 patients diagnosed with at least one chromosome abnormality. Each abnormality showed a unique comorbidity signature, but clustering of their profiles underlined common risk profiles for chromosome abnormalities with similar genetic backgrounds. We found that DS had a decreased risk for three inverse cancer comorbidities (lung, breast, and skin) and that male FXS and non-mosaic patients have a much more severe phenotype than female FXS and mosaic patients, respectively. CONCLUSION: Our study underlines the importance of considering mosaicism, sex, and the associated comorbidity profiles of chromosome abnormalities to guide long-term health care of affected patients.

Recognition and management of adults with Turner syndrome: From the transition of adolescence through the senior years.

Turner syndrome is recognized now as a syndrome familiar not only to pediatricians and pediatric specialists, medical geneticists, adult endocrinologists, and cardiologists, but also increasingly to primary care providers, internal medicine specialists, obstetricians, and reproductive medicine specialists. In addition, the care of women with Turner syndrome may involve social services, and various educational and neuropsychologic therapies. This article focuses on the recognition and management of Turner syndrome from adolescents in transition, through adulthood, and into another transition as older women. It can be viewed as an interpretation of recent international guidelines, complementary to those recommendations, and in some instances, an update. An attempt was made to provide an international perspective. Finally, the women and families who live with Turner syndrome and who inspired several sections, are themselves part of the broad readership that may benefit from this review.

Clinical experience with a single-nucleotide polymorphism-based non-invasive prenatal test for five clinically significant microdeletions.

Single-nucleotide polymorphism (SNP)-based non-invasive prenatal testing (NIPT) can currently predict a subset of submicroscopic abnormalities associated with severe clinical manifestations. We retrospectively analyzed the performance of SNP-based NIPT in 80 449 referrals for 22q11.2 deletion syndrome and 42 326 referrals for 1p36, cri-du-chat, Prader-Willi, and Angelman microdeletion syndromes over a 1-year period, and compared the original screening protocol with a revision that reflexively sequenced high-risk calls at a higher depth of read. The prevalence of these microdeletion syndromes was also estimated in the referral population. The positive predictive value of the original test was 15.7% for 22q11.2 deletion syndrome, and 5.2% for the other 4 disorders combined. With the revised protocol, these values increased to 44.2% for 22q11.2 and 31.7% for the others. The 0.33% false-positive rate (FPR) for 22q11.2 deletion syndrome decreased to 0.07% with the revised protocol. Similarly, the FPR for the other 4 disorders combined decreased from 0.56% to 0.07%. Minimal prevalences were estimated to be 1 in 1255 for 22q11.2 deletion syndrome and 1 in 1464 for 1p36, cri-du-chat, and Angelman syndromes combined. Our results show that these microdeletions are relatively common in the referral population, and that the performance of SNP-based NIPT is improved with high-depth resequencing.

Dual diagnoses in 152 patients with Turner syndrome: Knowledge of the second condition may lead to modification of treatment and/or surveillance.

Turner syndrome is a sex chromosome abnormality in which a female has a single X chromosome or structurally deficient second sex chromosome. The phenotypic spectrum is broad, and atypical features prompt discussion of whether the known features of Turner syndrome should be further expanded. With the advent of clinical whole exome sequencing, there has been increased realization that some patients with genetic disorders carry a second genetic disorder, leading us to hypothesize that a "dual diagnosis" may be more common than suspected for Turner syndrome. We report five new patients with Turner syndrome and a co-occurring genetic disorder including one patient with Li-Fraumeni syndrome, Li-Fraumeni and Noonan syndrome, mosaic trisomy 8, pathogenic variant in RERE, and blepharophimosis-ptosis-epicanthanus inversus syndrome. We also undertook an extensive literature review of 147 reports of patients with Turner syndrome and a second genetic condition. A total of 47 patients (31%) had trisomy 21, followed by 36 patients (24%) had one of 11 X-linked disorders. Notably, 80% of the 147 reported patients with a dual diagnosis had mosaicism for Turner syndrome, approximately twice the frequency in the general Turner syndrome population. This article demonstrates the potential for co-occurring syndromes in patients with Turner syndrome, prompting us to recommend a search for an additional genetic disorder in Turner patients with unusual features. Knowledge of the second condition may lead to modification of treatment and/or surveillance. We anticipate that increased awareness and improved diagnostic technologies will lead to the identification of more cases of Turner syndrome with a co-occurring genetic syndrome.

Investigating Pregnancy Outcomes After Abnormal Cell-Free DNA Test Results.

Cell-free DNA (cfDNA) testing has increased sensitivity and specificity compared to other prenatal screening methods, but invasive diagnostic testing (IDT) is recommended for confirmation. We performed a retrospective chart review of 39 women with abnormal cfDNA results between March 2012 and September 2015 at an urban academic hospital to evaluate patient choice and pregnancy outcomes. We analyzed data using descriptive statistics, Fisher's exact tests, and Wilcoxon rank-sum tests. Median maternal age was 36.0 years [interquartile range (IQR) 31, 39]; 64.1% of women (25/39) were advanced maternal age and 69.2% (27/39) had abnormal ultrasounds. Median gestational age at time of cfDNA testing was 18 3/7 weeks [IQR 12 2/7, 20 5/7]. cfDNA results included trisomy 21 (89.7%, 35/39), trisomy 18 (7.7%, 3/39), and both trisomy 21/monosomy X (2.6%, 1/39). Of 39 women, 22 (56.4%) continued and 10 (25.6%) terminated the pregnancy; six (15.4%) had fetal demises, and one was lost to follow-up. Of women continuing their pregnancies, 54.6% (12/22) declined further genetic counseling, and 77.3% (17/22) declined IDT. Only 14 women pursued IDT; not pursuing IDT was associated with continuing the pregnancy (Fisher's exact test, p = .001). All women terminating their pregnancy (90.0%, 9/10) pursued IDT or had major anomalies on ultrasound, suggesting that women considering termination undergo more confirmatory tests or already have high suspicion for an abnormal pregnancy.

Live births after simultaneous avoidance of monogenic diseases and chromosome abnormality by next-generation sequencing with linkage analyses.

In vitro fertilization (IVF), preimplantation genetic diagnosis (PGD), and preimplantation genetic screening (PGS) help patients to select embryos free of monogenic diseases and aneuploidy (chromosome abnormality). Next-generation sequencing (NGS) methods, while experiencing a rapid cost reduction, have improved the precision of PGD/PGS. However, the precision of PGD has been limited by the false-positive and false-negative single-nucleotide variations (SNVs), which are not acceptable in IVF and can be circumvented by linkage analyses, such as short tandem repeats or karyomapping. It is noteworthy that existing methods of detecting SNV/copy number variation (CNV) and linkage analysis often require separate procedures for the same embryo. Here we report an NGS-based PGD/PGS procedure that can simultaneously detect a single-gene disorder and aneuploidy and is capable of linkage analysis in a cost-effective way. This method, called "mutated allele revealed by sequencing with aneuploidy and linkage analyses" (MARSALA), involves multiple annealing and looping-based amplification cycles (MALBAC) for single-cell whole-genome amplification. Aneuploidy is determined by CNVs, whereas SNVs associated with the monogenic diseases are detected by PCR amplification of the MALBAC product. The false-positive and -negative SNVs are avoided by an NGS-based linkage analysis. Two healthy babies, free of the monogenic diseases of their parents, were born after such embryo selection. The monogenic diseases originated from a single base mutation on the autosome and the X-chromosome of the disease-carrying father and mother, respectively.