Prenatal diagnosis of acrania/exencephaly/anencephaly sequence (AEAS): additional structural and genetic anomalies.

OBJECTIVES: To analyse additional structural and genetic anomalies in fetuses with acrania/exencephaly/anencephaly sequence (AEAS). METHODS: A retrospective analysis of 139 fetuses with AEAS diagnosed between 2006 and 2020 in a single tertiary referral ultrasound department. RESULTS: The median gestational age at diagnosis decreased from 15 weeks in 2006 to 13 weeks in 2020 (- 0.21 per each year; p = 0.009). In 103 fetuses, the defects were limited to the neural tube (NTD) (74.1%), in 36 fetuses (25.9%), there were additional structural non-NTD anomalies. The most common were ventral body wall defects present in 17.8% (23/139), followed by anomalies of the limbs (7.2%; 10/139), face (6.5%; 9/139) and heart (6.5%; 9/139). Genetic anomalies were diagnosed in 7 of the 74 conclusive results (9.5%; 7/74; trisomy 18, n = 5; triploidy, n = 1; duplication of Xq, n = 1). In univariate logistic regression models, male sex, limb anomalies and ventral body wall defects significantly increased the risk of genetic anomalies (OR 12.3; p = 0.024; OR 16.5; p = 0.002 and OR 10.4; p = 0.009, respectively). CONCLUSIONS: A significant number of fetuses with AEAS have additional structural non-NTD anomalies, which are mostly consistent with limb body wall complex. Genetic abnormalities are diagnosed in almost 10% of affected fetuses and trisomy 18 is the most common aberration. Factors that significantly increased the odds of genetic anomalies in fetuses with AEAS comprise male sex, limb anomalies and ventral body wall defects.

Prenatal diagnosis of Emanuel syndrome - case series and review of the literature.

We present three new cases and review of the literature on the prenatal diagnosis of Emanuel syndrome (ES). Twenty-one foetuses have been analysed. In all three cases diagnosed in our department, posterior fossa abnormalities were seen and in one hypoplastic right ventricle was diagnosed at the first trimester scan. Defects of the posterior fossa (62% of foetuses; 13/21) and left diaphragmatic hernia (29% of foetuses; 6/21) are the most frequently reported prenatal findings in ES syndrome. No pattern of specific prenatal ultrasound markers of ES exists. Abnormalities of the posterior fossa are frequent and may be diagnosed as early as in the first trimester of pregnancy. Specific diagnosis can be made only after invasive genetic testing.IMPACT STATEMENTWhat is already known on this subject? Emanuel syndrome (ES) is a rare genetic disorder. No pattern of specific prenatal ultrasound markers exists. The great majority of cases is diagnosed postnatally and only a few cases of prenatal diagnosis have been published to date.What do the results of this study add? The most frequent structural abnormalities in prenatally detected ES involved central nervous system (80.9%), namely posterior fossa defects (57.1%) and mild ventriculomegaly (23.8%). Other frequent abnormalities include left diaphragmatic hernia (28.6%), renal defects (23.8%) and foetal growth restriction (FGR) (23.8%).What are the implications of these findings for clinical practice and/or further research? Abnormalities of the posterior fossa are the most frequent defects in ES and may be diagnosed as early as in the first trimester of pregnancy. Specific diagnosis can be made only after invasive genetic testing.

Implementation of Exome Sequencing in Prenatal Diagnosis and Impact on Genetic Counseling: The Polish Experience.

BACKGROUND: Despite advances in routine prenatal cytogenetic testing, most anomalous fetuses remain without a genetic diagnosis. Exome sequencing (ES) is a molecular technique that identifies sequence variants across protein-coding regions and is now increasingly used in clinical practice. Fetal phenotypes differ from postnatal and, therefore, prenatal ES interpretation requires a large amount of data deriving from prenatal testing. The aim of our study was to present initial results of the implementation of ES to prenatal diagnosis in Polish patients and to discuss its possible clinical impact on genetic counseling. METHODS: In this study we performed a retrospective review of all fetal samples referred to our laboratory for ES from cooperating centers between January 2017 and June 2021. RESULTS: During the study period 122 fetuses were subjected to ES at our institution. There were 52 abnormal ES results: 31 in the group of fetuses with a single organ system anomaly and 21 in the group of fetuses with multisystem anomalies. The difference between groups was not statistically significant. There were 57 different pathogenic or likely pathogenic variants reported in 33 different genes. The most common were missense variants. In 17 cases the molecular diagnosis had an actual clinical impact on subsequent pregnancies or other family members. CONCLUSIONS: Exome sequencing increases the detection rate in fetuses with structural anomalies and improves genetic counseling for both the affected couple and their relatives.

Comparative Genomic Hybridization to Microarrays in Fetuses with High-Risk Prenatal Indications: Polish Experience with 7400 Pregnancies.

The aim of this study was to determine the suitability of the comparative genomic hybridization to microarray (aCGH) technique for prenatal diagnosis, but also to assess the frequency of chromosomal aberrations that may lead to fetal malformations but are not included in the diagnostic report. We present the results of the aCGH in a cohort of 7400 prenatal cases, indicated for invasive testing due to ultrasound abnormalities, high-risk for serum screening, thickened nuchal translucency, family history of genetic abnormalities or congenital abnormalities, and advanced maternal age (AMA). The overall chromosomal aberration detection rate was 27.2% (2010/7400), including 71.2% (1431/2010) of numerical aberrations and 28.8% (579/2010) of structural aberrations. Additionally, the detection rate of clinically significant copy number variants (CNVs) was 6.8% (505/7400) and 0.7% (57/7400) for variants of unknown clinical significance. The detection rate of clinically significant submicroscopic CNVs was 7.9% (334/4204) for fetuses with structural anomalies, 5.4% (18/336) in AMA, 3.1% (22/713) in the group of abnormal serum screening and 6.1% (131/2147) in other indications. Using the aCGH method, it was possible to assess the frequency of pathogenic chromosomal aberrations, of likely pathogenic and of uncertain clinical significance, in the groups of cases with different indications for an invasive test.

Prenatal Diagnosis by Array Comparative Genomic Hybridization in Fetuses with Cardiac Abnormalities.

Congenital heart defects (CHDs) appear in 8-10 out of 1000 live born newborns and are one of the most common causes of deaths. In fetuses, the congenital heart defects are found even 3-5 times more often. Currently, microarray comparative genomic hybridization (array CGH) is recommended by worldwide scientific organizations as a first-line test in the prenatal diagnosis of fetuses with sonographic abnormalities, especially cardiac defects. We present the results of the application of array CGH in 484 cases with prenatally diagnosed congenital heart diseases by fetal ultrasound scanning (256 isolated CHD and 228 CHD coexisting with other malformations). We identified pathogenic aberrations and likely pathogenic genetic loci for CHD in 165 fetuses and 9 copy number variants (CNVs) of unknown clinical significance. Prenatal array-CGH is a useful method allowing the identification of all unbalanced aberrations (number and structure) with a much higher resolution than the currently applied traditional assessment techniques karyotype. Due to this ability, we identified the etiology of heart defects in 37% of cases.

Triploid pregnancy-Clinical implications.

Triploidy is a life-limiting genetic aberration resulting from an extra haploid set of chromosomes of paternal (diandric triploidy) or maternal origin (digynic triploidy). Triploidy affects around 1%-2% of all conceptions. The majority of cases is miscarried at early developmental stages. In consequence of genomic imprinting, parental origin affects the phenotype of triploid pregnancies as well as the prevalence and spectrum of related maternal complications. Distinctive ultrasound features of both triploid phenotypes as well as characteristic patterns of biochemical markers may be useful in diagnosis. Molecular confirmation of the parental origin allows to predict the risk of complications, such as gestational trophoblastic neoplasia, hyperthyroidism, hypertension, or preeclampsia associated with the paternal origin of triploidy. Diagnosis of partial hydatidiform mole associated with diandric triploidy is challenging especially in the first trimester pregnancy loss due to the limitations of both histopathology and ultrasound. We present important clinical aspects of triploid pregnancies and indicate unresolved issues demanding further studies.

Distribution of diandric and digynic triploidy depending on gestational age.

PURPOSE: To establish the distribution of diandric and digynic triploidy depending on gestational age. METHODS: 107 triploid samples tested prospectively in a single genetic department during a four-year period were analyzed for parental origin of triploidy by Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) (n=95) with the use of matching parental samples or by MS-MLPA (n=12), when parental samples were unavailable. Tested pregnancies were divided into three subgroups with regard to the gestational age at spontaneous pregnancy loss: <11 gestational weeks, 11-14 gestational weeks, and >14 gestational weeks. RESULTS: Diandric triploidy constituted overall 44.9% (46.5% in samples miscarried <11 gestational weeks, 64.3% in samples miscarried between 11 and 14 gestational weeks, and 27.8% in pregnancies which survived >14 gestational weeks). CONCLUSIONS: The distribution of diandric and digynic triploidy depends on gestational age. The majority of diandric triploid pregnancies is lost in the first trimester of pregnancy. In the second trimester, diandric cases are at least twice less frequent than digynic ones.

A placental trisomy 2 detected by NIPT evolved in a fetal small Supernumerary Marker Chromosome (sSMC).

BACKGROUND: Non-invasive prenatal testing (NIPT) is a rapidly developing and widely used method in the prenatal screening. Recently, the widespread use of the NIPT caused a neglecting of the limitations of this technology. CASE PRESENTATION: The 38-year-old woman underwent amniocentesis because of a high risk of trisomy 2 revealed by the genome-wide Non-Invasive Prenatal Test (NIPT). The invasive prenatal diagnosis revealed the mosaicism for a small supernumerary marker chromosome sSMC derived from chromosome 2. Interphase fluorescence in situ hybridization (FISH) on uncultured amniocytes revealed three signals of centromere 2 in 30% of the cells. GTG-banded metaphases revealed abnormal karyotype (47,XX,+mar[21]/46,XX[19]) and was confirmed by array comparative genomic hybridization (aCGH). Cytogenetic analyses (FISH, aCGH, karyotype) on fetal skin biopsies were performed and confirmed the genomic gain of the centromeric region of chromosome 2. In the placenta, three cell lines were detected: a normal cell line, a cell line with trisomy 2 and a third one with only the sSMC. CONCLUSION: Whole-genome Non-Invasive Prenatal Testing allows not only the identification of common fetal trisomies but also diagnosis of rare chromosomal abnormalities. Especially in such cases, it is extremely important to perform not only NIPT verification on a sample of material other than trophoblast, but also to apply appropriate research methods. Such conduct allows detailed analysis of the detected aberration, thus appropriate clinical validity.

Twin pregnancies discordant for digynic triploidy - A case series.

OBJECTIVE: To analyse natural course and perinatal management in twin pregnancies discordant for digynic triploidy. CASE REPORT: We present five cases of twins discordant for digynic triploidy. Pregnancy outcome was known for three of them. In one case, premature rupture of membranes occurred at 20 gestational weeks and both fetuses were miscarried. In two other pregnancies healthy co-twins were born at term after the triploid fetuses demise at 28 and 37 weeks. No maternal complications were observed. CONCLUSION: Twin pregnancies discordant for triploidy poses a challenge for perinatal management. Expectant management should be considered in digynic triploid cases.

Prenatal diagnosis of glutaric acidemia type 2 with the use of exome sequencing - an up-to-date review and new case report.

INTRODUCTION: Inborn errors of metabolism (IEM) also called metabolic diseases constitute a large and heterogenous group of disorders characterized by a failure of essential cellular functions. Antenatal manifestation of IEM is absent or nonspecific, which makes prenatal diagnosis challenging. Glutaric acidemia type 2 (GA2) is a rare metabolic disease clinically manifested in three different ways: neonatal-onset with congenital anomalies, neonatal-onset without congenital anomalies and late-onset. Neonatal forms are usually lethal. Congenital anomalies present on prenatal ultrasound as large, hyperechoic or cystic kidneys with reduced amniotic fluid volume. MATERIAL AND METHODS: We present a systematic literature review describing prenatal diagnosis of GA2 and a new prenatal case. RESULTS: Ten prenatally diagnosed cases of GA2 have been published to date, mainly based on biochemical methods. New case of GA2 was diagnosed using exome sequencing method. DISCUSSION: All prenatal cases from literature review had positive history of GA2 running in the family. In our study trio exome sequencing was performed in case of fetal hyperechoic kidneys without a history of GA2. Consequently, we were able to identify two novel pathogenic variants of the ETFDH gene and to indicate their parental origin. SUMMARY: Exome sequencing approach used in case of fetal hyperechoic kidneys allows to identify pathogenic variants without earlier knowledge of the precise genetic background of the disease. Hyperechoic, enlarged kidneys could be one of the clinical features of metabolic diseases. After exclusion of chromosomal abnormalities, urinary tract obstruction and intrauterine infections, glutaric acidemia type 2 and number of monogenic disorders should be consider.

Usefulness of methylation-specific multiplex ligation-dependent probe amplification for identification of parental origin of triploidy.

Triploidy is a genetic aberration resulting from an extra haploid set of chromosomes of paternal (diandric) or maternal (digynic) origin. Diandric cases, opposite to digynic ones, may lead to gestational trophoblastic neoplasia (GTN) or generate maternal complications, therefore their identification is crucial, but reproducibility of traditionally used histopathological assessment is poor. The aim of the study was to analyse the usefulness of methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) with probes for two differentially methylated regions (DMR) at chromosome 11p.15.5 for identification of the parental origin of triploidy. 84 triploid DNA samples were tested with MS-MLPA: 34 paternal cases (40.5%) and 50 maternal ones (59.5%) according to the reference results of QF-PCR. Methylation ratio (MR) was calculated. Reference values proposed by the MRC-Holland for diploid samples (MR 0.8-1.2) were used. The values outside these ranges were used to diagnose parental origin of triploidy-paternal (MR > 1.2) or maternal (MR < 0.8). The effectiveness of MS-MLPA was 94.0%. The mean MR in paternal triploidy was 1.7 (SD-0.25; n = 34) compared with 0.56 in maternal triploidy (SD-0.12; n = 50). MR values in paternal and maternal triploidy did not overlap. In five samples (6.0%) parental origin of triploidy could not be accurately established by MS-MLPA, probably due to the maternal cell contamination (MCC). MS-MLPA can be used as a convenient method for distinguishing between paternal and maternal triploidy without the necessity for parental samples testing. It enables adequate selection of the paternal triploid cases for follow up in order to exclude post-molar GTN.

In-house genetic counseling increases the detection of abnormal karyotypes-a 26-year experience in prenatal diagnosis in a single tertiary referral hospital in Poland.

PURPOSE: To evaluate the trends in prenatal diagnosis over 26 years in a tertiary referral hospital. METHODS: A retrospective analysis of invasive prenatal procedures performed between 1991 and 2016. Maternal characteristics, indications for invasive diagnosis, and percentage of abnormal karyotypes were compared between periods according to guidelines implemented nationally and locally. RESULTS: A total of 14,302 invasive prenatal procedures were performed. The proportion of invasive procedures performed for advanced maternal age, abnormal karyotype in a previous pregnancy, and maternal anxiety decreased from 71.1%, 17.8%, 8.9% in 1991 to 23.9%, 1.3%, and 2.3% in 2016 (OR 0.6, 0.8, and 0.9 for each 5 years, respectively; p < 0.001), while the proportion of invasive procedures performed for abnormal ultrasound increased from 2.2% in 1991 to 51.6% in 2016 (OR 1.9 for each 5 years; p < 0.001). Abnormal karyotype was found in 9.7%. The proportion of abnormal karyotypes increased significantly from 0.0% in 1991 to 15.7% in 2016 (OR 1.35 for each 5-year period; p < 0.001). The odds of abnormal karyotype increased after the implementation of the Ordinance of the Minister of Health in 2003 (OR 1.6), the National Prenatal Screening Program in 2007 (OR 2.2), and the in-house genetic counseling with combined first trimester screening in 2015 (OR 3.1). CONCLUSIONS: Significant changes in prenatal diagnosis led to a better selection of patients undergoing invasive prenatal procedures. The implementation of in-house genetic counseling was associated with an increased rate of the detection of abnormal karyotypes.

Prenatal diagnosis and clinical significance of cephalocele-A single institution experience and literature review.

OBJECTIVES: To determine the frequency of genetic and additional structural abnormalities as well as pregnancy outcomes in fetuses with prenatally diagnosed cephalocele. METHODS: A retrospective analysis of data retrieved from ultrasound examinations and genetic testing in fetuses with cephalocele diagnosed between 2006 and 2018 in a tertiary referral hospital along with a systematic literature search in the PubMed database on fetuses with prenatally diagnosed cephalocele. RESULTS: Twenty-one out of 36 fetuses were found to have additional structural anomalies (58.3%). In four fetuses, anomalies were consistent with limb-body wall complex, in five with Meckel-Gruber syndrome, and in one with amniotic band syndrome. Genetic abnormalities were present in 11.1% of fetuses (trisomy 6; microdeletion 22q11.21; microduplication 16p13.11; pathogenic variant in gene CC2D2A). Twenty-eight pregnancies were terminated (77.8%; 28/36); two were miscarried (5.6%; 2/36). All six children from pregnancies that continued were liveborn but only two survived the surgery and developed neurological sequence. Overall survival rate was 25% (2/8) with 0% intact survival. CONCLUSIONS: Additional structural anomalies are common in fetuses with cephalocele. A significant number of fetuses have genetic abnormalities, and a detailed genetic testing should be performed in all cases. The prognosis is poor with high mortality rate and 0% intact survival.

The role of ultrasound and genetic counsel in prenatal diagnosis of split hand/foot malformation with long bone deficiency.

OBJECTIVE: The aim of the report is to highlight importance of careful ultrasound examination and genetic counsel in case of split hand/foot prenatal diagnosis. Evaluation of the accompanying long bone deficiency indicates that array comparative genomic hybridization (aCGH) should be used. CASE REPORT: We present a prenatal diagnosis of split hand/foot malformation with long bone deficiency type 3 (SHFLD3) in a patient suffering from congenital limb anomalies but without previous molecular diagnosis. Genetic consultation and prenatal testing were offered. While karyotype was normal, aCGH revealed microduplication in locus 17p33.3. Microarray analysis was carried out also in pregnant patient and her asymptomatic mother and gave positive results on both. CONCLUSION: Prenatal diagnosis of SHFLD3 either imaging or cytogenetic is possible. Both methods should be used to make a correct diagnosis. Due to reduced penetrance of SHFLD3 not all individuals carrying microduplication present clinical findings. Therefore, pedigree analysis and genetic counsel is important for whole family and not only for affected members. Advances in genetics may allow to establish exact diagnosis in previously undiagnosed patients.

The location of the fetal ears: A hint for prenatal diagnosis of agnathia-otocephaly complex.

Otocephaly is an extremely rare lethal congenital anomaly characterized by the absence or underdevelopment of the mandible. The clinical presentation is variable. Some cases may present with severe micrognathia as the only anomaly seen prenatally. The key to early diagnosis is careful assessment of the location of the fetal ears on 2D ultrasound examination.

Complex malformations involving the fetal body wall - definition and classification issues.

OBJECTIVE: The objective of the study is to analyse the sonographic features, cytogenetic results and pregnancy outcomes in complex malformations involving the body wall in a large cohort of fetuses with regard to different definitions proposed in the literature. METHOD: A retrospective study on 96 fetuses with complex malformations comprising ventral wall, craniofacial structures, limbs and umbilical cord that were evaluated between 1997 and 2015. RESULTS: The most common sonographic finding was an extensive ventral wall defect (95.8%; 92/96) comprising liver (94.6%; 87/92), intestine (82.6%; 76/92), heart (17.4%; 16/92) and bladder (8.7%; 8/92). Acrania and encephalocoele were observed in 24 and 9 fetuses (25.0%, 24/96; 9.4%, 9/96), respectively. Limb anomalies were present in 54 fetuses (56.3%; 54/96). Rudimentary or absent umbilical cord was observed in 62 fetuses (64.6%; 62/96). In 79 fetuses, there were additional multiple structural anomalies detected prenatally. None of the currently used definitions encompasses all possible phenotypes of body wall defects present in our cohort. Chromosomal aberrations were seen in 8 out of 60 cases with conclusive cytogenetic result (13.3%, 8/60). CONCLUSION: Chromosomal anomalies are common, and karyotyping should be offered. There is a need for a more rigorous classification of complex malformations in order to better understand the underlying pathophysiology. © 2017 John Wiley & Sons, Ltd.

Prenatal diagnosis of Duchenne and Becker muscular dystrophies: Underestimated problem of the secondary prevention of monogenetic disorders.

AIM: The aim of this study was to analyze the influence of effective preconceptional testing for carrier status in women at risk for Duchenne and Becker muscular dystrophies (D/BMD) on the prenatal diagnosis. METHODS: A retrospective analysis of 201 prenatal tests was performed in 169 Polish women at risk, in regard to time of testing for carrier status (prior to conception or during pregnancy) and carrier status of tested women, including confirmed D/BMD carriers (n = 78; 46.2%), D/BMD non-carriers - tested for germline mosaicism risk (n = 23; 13.6%), and women at risk with uncertain carrier status (n = 68; 40.2%). RESULTS: Only 52.7% of women were tested for D/BMD carrier status prior to conception and in these women prenatal diagnosis was carried out more frequently in the first trimester of pregnancy (64.7% vs 47.8%; P = 0.035). The results of prenatal testing in male fetuses in pregnancies of confirmed D/BMD carriers and D/BMD non-carriers - tested for germline mosaicism risk were conclusive in all cases, whereas in women with uncertain carrier status, only 60.0% of results were conclusive. Eighty-five of 103 female fetuses (82.5%) were tested prenatally and in 31.8% of them fetal carrier status was confirmed. CONCLUSION: Carrier status testing in women prior to conception has a positive impact on the frequency of first-trimester prenatal diagnosis and known D/BMD carrier status on the effectiveness of prenatal diagnosis. Due to the low percentage of women tested effectively prior to conception, carrier status testing in the families at risk should be propagated (including possibility of prenatal diagnosis of female fetuses).

Triploidy - variability of sonographic phenotypes.

OBJECTIVES: To analyze sonographic abnormalities in triploid pregnancies and assess the usefulness of the classification proposed by McFadden and Kalousek for prenatal sonographic assessment of triploid fetuses. METHODS: We conducted a retrospective analysis of the sonographic features in a series of 67 triploid fetuses evaluated between 11 and 30 weeks of gestation in a single referral center between 1997 and 2015. RESULTS: Non-specific structural fetal defects were visualized in the majority of fetuses (61.2%) regardless of the parental origin of the triploidy. A 'diandric phenotype' was identified in eight relatively well-grown fetuses (11.9%) that presented with cystic placentas. A 'digynic phenotype' was identified in 47 asymmetrically growth-restricted fetuses with non-cystic placentas (70.2%). In 12 cases (17.9%), features of both phenotypes were present. CONCLUSIONS: Nearly 40% of triploid fetuses do not have any apparent structural abnormalities, and only careful assessment of fetal growth and placenta may lead to the suspicion of the diagnosis. As diandric triploidy carry a high risk for maternal complications, identification of these cases is vital for prenatal counseling. In nearly 20% of triploid pregnancies, parental origin cannot be established based on sonographic assessment. © 2017 John Wiley & Sons, Ltd.