Prenatal diagnosis of 18p deletion and 8p trisomy syndrome: literature review and report of a novel case.

18p deletion syndrome constitutes one of the most frequent autosomal terminal deletion syndromes, affecting one in 50,000 live births. The syndrome has un-specific clinical features which vary significantly between patients and may overlap with other genetic conditions. Its prenatal description is extremely rare as the fetal phenotype is often not present during pregnancy. Trisomy 8p Syndrome is characterized by heterogenous phenotype, with the most frequent components to be cardiac malformation, developmental and intellectual delay. Its prenatal diagnosis is very rare due to the unspecific sonographic features of the affected fetuses. We present a very rare case of a fetus with multiple anomalies diagnosed during the second trimester whose genomic analysis revealed a 18p Deletion and 8p trisomy Syndrome. This is the first case where this combination of DNA mutations has been described prenatally and the second case in general. The presentation of this case, as well as the detailed review of all described cases, aim to expand the existing knowledge regarding this rare condition facilitating its diagnosis in the future.

The Effect of Resolution Level and Targeted Design in the Diagnostic Performance of Prenatal Chromosomal Microarray Analysis.

INTRODUCTION: This study was performed to assess the optimal resolution for prenatal testing by array comparative genomic hybridization (aCGH), aiming to balance between maximum diagnostic yield and minimal detection of variants of uncertain significance (VOUS). METHODS: This was a prospective study using data of 2,336 fetuses that underwent invasive prenatal diagnosis, and the samples were analyzed by aCGH. In total, six different aCGH platforms were studied; four different resolutions (0.18 Mb, 0.5 Mb, 1 Mb, and 2 Mb) and two platform designs (whole-genome [WG] and targeted). The results of these designs were compared based on their diagnostic yield and VOUS rate. The performance of the different designs was further analyzed according to indication for invasive testing. RESULTS: The diagnostic yield of copy number variants increased with increasing level of analysis. The detection rates of clinically significant chromosomal abnormalities were almost the same across our targeted array designs; 7.2% with 0.18 Mb backbone/0.05 Mb versus 7.1% with 0.5 Mb backbone/0.05 Mb (p >0.05). However, a significant difference in the rate of VOUS was observed; 9.4% with 0.18 Mb backbone/0.05 Mb versus 6% with 0.5 Mb backbone/0.05 Mb (p <0.001). After analyzing the results across different indications for testing, we found that the application of non-targeted platform designs and lower levels of resolution analysis (such as 1 Mb WG or 0.5 MbL/1 MbG WG) would offer similar diagnostic yield in most cases with major congenital anomalies, with lower VOUS rates. However, the sample size for many indication groups was too small to extract robust associations. CONCLUSION: It appears that the targeted array platform with 0.5 Mb backbone resolution and 0.05 Mb on targeted gene-rich regions is optimal for routine chromosomal microarray analysis use in prenatal diagnosis. It may be beneficial to individualize the minimum resolution in specific referral indications as the indications for invasive prenatal testing may be quite heterogeneous.

Small supernumerary marker chromosomes: A legacy of trisomy rescue?

We studied by a whole genomic approach and trios genotyping, 12 de novo, nonrecurrent small supernumerary marker chromosomes (sSMC), detected as mosaics during pre- or postnatal diagnosis and associated with increased maternal age. Four sSMCs contained pericentromeric portions only, whereas eight had additional non-contiguous portions of the same chromosome, assembled together in a disordered fashion by repair-based mechanisms in a chromothriptic event. Maternal hetero/isodisomy was detected with a paternal origin of the sSMC in some cases, whereas in others two maternal alleles in the sSMC region and biparental haplotypes of the homologs were detected. In other cases, the homologs were biparental while the sSMC had the same haplotype of the maternally inherited chromosome. These findings strongly suggest that most sSMCs are the result of a multiple-step mechanism, initiated by maternal meiotic nondisjunction followed by postzygotic anaphase lagging of the supernumerary chromosome and its subsequent chromothripsis.

A Girl with 10 Mb Distal Xp Deletion Arising from Maternal Pericentric Inversion: Clinical Data and Molecular Characterization.

BACKGROUND: Short arm deletions of the X-chromosome are challenging issues for genetic counseling due to their low penetrance in population. Female carriers of these deletions have milder phenotype than male ones, considering the intellectual ability and social skills, probably because of the X-chromosome inactivation phenomenon. CASE REPORT: A female patient with a 10Mb distal Xp deletion and an Xq duplication, showing mild intellectual disability, is described in this report. While the deletion arose from a maternal pericentric inversion, the duplication was directly transmitted from the mother who is phenotypically normal. CONCLUSION: This report underlines the usefulness of molecular cytogenetic technics in postnatal diagnosis.

Non-invasive prenatal screening versus prenatal diagnosis by array comparative genomic hybridization: a comparative retrospective study.

OBJECTIVE: To calculate the proportion of array comparative genomic hybridization (aCGH) pathogenic results, that would not be detectable by non-invasive prenatal screening (NIPS). METHODS: This is a comparative study using data from 2779 fetuses, which underwent invasive prenatal diagnosis, and the samples were analyzed using aCGH. The simulated NIPS assay would test for trisomies 21, 18, 13, monosomy X, 47, XXX, 47, XYY, and 47, XXY. Indications for invasive testing were grouped into categories and the absolute, relative rates of pathogenic/likely pathogenic results of aCGH analysis that would not be detectable by NIPS were calculated. RESULTS: The expected rate of aCGH-detected abnormalities that would not be detectable by NIPS was 28.0% (95% CI 14.3-47.6) for nuchal translucency (NT) 95 to 99th centile; 14.3% (95% 5.0-34.6) for NT > 99th centile; 34.2% (95% CI 21.1-50.1) for high-risk first-trimester results (regardless of NT); 52.4% (95% CI 32.4-71.7) for second-trimester markers; and 50.0% (95% CI 26.8-73.2) for advanced maternal age. The overall rate of aCGH pathogenic/likely pathogenic results was 5.0% and 44.0% (95% CI 36.0-52.2) of them would not be detected by NIPS. CONCLUSIONS: Approximately half of the abnormal aCGH results would not be detectable by standard NIPS assays, highlighting the necessity of pre-test counseling, and illustrating the limitations of NIPS. © 2017 John Wiley & Sons, Ltd.

Deletion of 4.4 Mb at 2q33.2q33.3 May Cause Growth Deficiency in a Patient with Mental Retardation, Facial Dysmorphic Features and Speech Delay.

A patient with a rare interstitial deletion of chromosomal band 2q33.2q33.3 is described. The clinical features resembled the 2q33.1 microdeletion syndrome (Glass syndrome), including mental retardation, facial dysmorphism, high-arched narrow palate, growth deficiency, and speech delay. The chromosomal aberration was characterized by whole genome BAC aCGH. A comparison of the current patient and Glass syndrome features revealed that this case displayed a relatively mild phenotype. Overall, it is suggested that the deleted region of 2q33 causative for Glass syndrome may be larger than initially suggested.

Complex Rearrangement Involving Three Chromosomes, Four Breakpoints and a 2.7-Mb Deletion in the 18q Segment Observed in a Girl with Mild Learning Difficulties.

Complex chromosomal rearrangements (CCRs) are balanced or unbalanced structural rearrangements involving 3 or more cytogenetic break events on 2 or more different chromosomes. Here, we report a 7-year-old girl referred to our unit because of mild dysmorphic facial features, mild learning difficulties together with very mild mental retardation. Standard cytogenetic banding analysis revealed a de novo CCR involving chromosomes 1, 2 and 18. Further molecular investigation with aCGH revealed a cryptic interstitial deletion of 2.7 Mb in 18q22.1, which does not elicit a significant clinical phenotype. FISH was performed to confirm both molecular and cytogenetic results.

Routine use of array comparative genomic hybridization (aCGH) as standard approach for prenatal diagnosis of chromosomal abnormalities. Clinical experience of 1763 prenatal cases.

OBJECTIVE: This study aims to evaluate the diagnostic yield of comparative genomic hybridization microarrays (aCGH) and compare it with conventional karyotype analysis of standard >5-Mb resolution. METHOD: A total of 1763 prenatal samples were analyzed by aCGH (CytoChip Focus Constitutional microarrays, BlueGnome, Cambridge). The diagnostic yield of chromosomal abnormalities detected by aCGH was assessed, compared with conventional karyotype analysis. RESULTS: The result was pathogenic/unknown penetrance in 125 cases (7.1%), and a variant of unknown significance (VOUS) was detected in 13 cases (0.7%). Out of the 125 cases with abnormal findings, 110 were also detected by conventional karyotype analysis. The aCGH increment in diagnostic yield was 0.9% (15/1763) and 1.6% when VOUS were included. Stratifying the sample according to indications for prenatal invasive testing, the highest values of diagnostic yield increment were observed for patients positive for second-trimester sonographic markers (1.5%) and for the presence of fetal structural anomalies (1.3%). In contrast, the incremental yield was marginal in patients with fetus with increased nuchal translucency (0.5%). CONCLUSION: The present study indicates that routine implementation of aCGH offers an incremental yield over conventional karyotype analysis, which is also present in cases with 'milder' indications, further supporting its use as a first-tier test.

An interstitial 4q31.21q31.22 microdeletion associated with developmental delay: case report and literature review.

The 4q deletion syndrome phenotype consists of growth failure and developmental delay, minor craniofacial dysmorphism, digital anomalies, and cardiac and skeletal defects. We have identified an inversion (inv(1)(q25.2q31.1)) and an interstitial deletion in a boy with developmental delay using array-comparative genomic hybridization. This de novo deletion is located at 4q31.21q31.22 (145,963,820- 147,044,764), its size is 0.9-1.1 Mb, and it contains 7 genes (ABCE1, OTUD4, SMAD1, MMAA, C4orf51, ZNF827, and ANAPC10) as well as 5 retrotransposon-derived pseudogenes. Bioinformatic analysis revealed that while small copy number variations seem to have no impact on the phenotype, larger deletions or duplications in the deleted region are associated with developmental delay. Additionally, we found a higher coverage in transposable element sequences in the 4q31.21q31.22 region compared to that of the expected repeat density when regarding any random genome region. Transposable elements might have contributed to the reshaping of the genome architecture and, most importantly, we identified 3 L1PA family members in the breakpoint regions, suggesting their possible contribution in the mechanism underlying the appearance of this deletion. In conclusion, this is one of the smallest deletions reported associated with developmental delay, and we discuss the possible role of genomic features having an impact on the phenotype.

Prenatal diagnosis of proximal partial trisomy 1q confirmed by comparative genomic hybridization array: molecular cytogenetic analysis, fetal pathology and review of the literature.

BACKGROUND: Partial trisomy of the long arm of chromosome 1 (1q) is an exceptionally rare chromosomal abnormality and most of the prenatally diagnosed cases are associated with either complete (q11-qter) or large (q21-qter) duplications with pre- or perinatal demise of all reported cases. The most common sonographic findings associated with this karyotype abnormality include ventriculomegaly, increased nuchal translucency or nuchal fold, renal and cardiac abnormalities, craniofacial dysmorphism, and limb deformities. However, there is a wide spectrum of clinical manifestations due to the great variability in the extent of the duplication size and the possible contribution of additional genetic rearrangements in the final phenotype. CASE REPORT: We report on a female fetus with sole partial trisomy 1q presenting with multiple structural malformations in the second trimester scan. Standard karyotyping demonstrated a large duplication on the proximal end of chromosome 1 [46,XX,dup(1)(pter→q31::q31→q12::q31→qter)] and further application of comparative genomic hybridization array confirmed the diagnosis and offered a precise characterization of the genetic defect. CONCLUSION: A fetus with nonmosaic partial trisomy 1q that was prenatally diagnosed upon multiple abnormal ultrasound findings is presented. A detailed review of the currently available literature on the prenatal diagnostic approach of partial trisomy 1q in terms of fetal sonographic assessment and molecular cytogenetic investigation is also provided. The use of novel molecular techniques such comparative genomic hybridization array could shed further light on the correlation between the genes identified in the chromosomal region of interest and the resultant phenotype.

Prenatal Identification of a Missense Mutation of the L1CAM Gene Associated With Hydrocephalus Using Next-Generation Sequencing.

We present the case of a 35-year-old pregnant woman who visited our department for a routine ultrasonography screening scan for fetus anatomy during the 22nd week of gestation. Our report revealed a male fetus with marked hydrocephalus and severe intrauterine growth retardation. After extensive counseling, the couple decided to proceed with an invasive diagnosis via amniocentesis. The cytogenetic analysis showed findings related to clinical history and ultrasound findings related to the presence of a nucleotide change in c.578T>C with an amino acid change in p.Leu198Pro of the L1CAM gene. The result was reported as a hemizygote missense L1CAM gene variant of unknown significance. After extensive parental counseling, the couple decided on pregnancy termination. We report the present case of L1CAM mutation in p.Leu198Pro to add to the limited knowledge regarding the clinical presentation of mutations of the L1CAM gene with emphasis on prenatal diagnosis.

An asymptomatic male individual carrying a 5.72 Mb de novo deletion in 8p23.2­p23.3: A case report.

Numerous rearrangements in the 8p23 chromosomal region have been reported; included in these rearrangements are isolated deletions in this area. Such deletions are associated with a wide range of phenotypic characteristics, including motor impairment, epilepsy, intellectual disability, cardiac defects and seizures. The present study describes the case of a 30-year-old asymptomatic man that carries a de novo deletion in 8p23.2-p23.3. Molecular karyotyping indicated that the detected deletion involves genes that are in the critical region which is hypothesized to be responsible for the phenotypic characteristics associated with such deletions. The normal phenotype of the patient supports the hypothesis that there is incomplete penetrance of 8p23.2-p23.3 deletions.

Dual testing with QF-PCR and karyotype analysis for prenatal diagnosis of chromosomal abnormalities. Evaluation of 13,500 cases with consideration of using QF-PCR as a stand-alone test according to referral indications.

OBJECTIVE: Evaluate the results obtained from Quantitative Fluorescent (QF)-PCR and conventional karyotype analysis to determine the advantages and disadvantages of dual testing in prenatal diagnosis. METHODS: From 1 June 2006 to 1 June 2010, dual testing by QF-PCR and karyotype analysis was performed in 13,500 prenatal samples. The rates of concordant results between the two methods were evaluated and the rates of clinically significant chromosomal abnormalities undetected by QF-PCR were assessed. RESULTS: Abnormal karyotype was found in 320 out of 13,500 cases (2.37%, 95% confidence interval (CI) 2.11-2.63%). From these, QF-PCR did not detect the abnormality in 70 cases (0.52%, 95% CI 0.4-0.64%), whereas 34 had a high/unknown risk of adverse outcome (0.25%, 95% CI 0.17-0.33%). By selectively applying dual testing only at cases with ultrasound findings and/or genetic history, 13 cases of high/unknown risk would have been missed (0.1%, 95% CI 0.05-0.15%). CONCLUSION: Selective dual testing is expected to achieve a serious beneficial economical outcome and reduce parental anxiety produced by ambiguous cytogenetic findings. However, the percentage of 0.1% undetected clinically significant abnormalities cannot be ignored. A suggestion would include the offering of a choice to the pregnant women, undergoing prenatal screening, by informing them about different approaches and various complications.

Sonographic antenatal diagnosis of congenital dacryocystoceles.

Congenital dacryocystoceles are a relatively rare variant of nasolacrimal duct obstruction, accounting for only 0.1% of infants with congenital nasolacrimal duct obstruction. We report a new case of bilateral congenital dacrocystoceles diagnosed in an otherwise uncomplicated fetal ultrasound examination during the 33rd week of pregnancy. The diagnosis was confirmed postnatally. The neonate, who did not present postpartum respiratory distress, was scheduled for endoscopic marsupialization-probing of the cystic structures. Parents must be well informed about the risk of respiratory distress, and facial appearance. Complete resolution is achieved after surgical intervention.

Growth Hormone Deficiency due to p.(Gln467Argfs*64) Mutation in the ARID1B Gene in a Girl with Coffin-Siris Syndrome.

Introduction: Coffin-Siris syndrome (CSS) (MIM #135900) is an extremely rare genetic multisystemic disorder characterized by aplasia or hypoplasia of the upper phalanx of the fifth finger, moderate to severe cognitive and/or developmental delay, and characteristic facial features (thick lashes, hypertrichosis of the trunk, sparse hair). Congenital anomalies of the brain, kidney, and heart have been described but are less consistent across patients. Case presentation: We report a case of a 12-year-5-month-old girl with the clinical features of CSS, severe scoliosis, and epilepsy. Growth hormone deficiency was diagnosed at the age of 9 years. Recombinant human growth hormone (rhGH) treatment was started that resulted in a significant improvement of the growth velocity up to 5.4 cm/year (>90-97th centile). Next-generation sequencing identified a mutation in the ARID1B gene. Discusion: Despite its phenotypic heterogeneity, key features of CSS have become clearer and along with molecular diagnosis, a further global approach to improve the care of these individuals is enabled. Appropriate therapies for this population are needed to optimize growth and intellectual potentials.

Prenatal Identification of a Novel Mutation in the MCPH1 Gene Associated with Autosomal Recessive Primary Microcephaly (MCPH) Using Next Generation Sequencing (NGS): A Case Report and Review of the Literature.

BACKGROUND: MCPH1 is known as the microcephalin gene (OMIM: *607117), of which the encoding protein is a basic regulator of chromosome condensation (BCRT-BRCA1 C-terminus). The microcephalin protein is made up of three BCRT domains and conserved tandem repeats of interacting phospho-peptides. There is a strong connection between mutations of the MCPH1 gene and reduced brain growth. Specifically, individuals with such mutations have underdeveloped brains, varying levels of mental retardation, delayed speech and poor language skills. METHODS: In this article, a family with two affected fetuses presenting a mutation of the MCPH1 gene is reported. During the first trimester ultrasound of the second pregnancy, the measure of nuchal translucency was increased (NT = 3.1 mm) and, therefore, the risk for chromosomal abnormalities was high. Chorionic villi sampling (CVS) was then performed. Afterwards, fetal karyotyping and Next Generation Sequencing were carried out. Afterwards, NGS was also performed in a preserved sample of the first fetus which was terminated due to microcephaly. RESULTS: In this case, the fetuses had a novel homozygous mutation of the MCPH1 gene (c.348del). Their parents were heterozygous for the mutation. The fetuses showed severe microcephaly. Because of the splice sites in introns, this mutation causes the forming of dysfunctional proteins which lack crucial domains of the C-terminus. CONCLUSION: Our findings portray an association between the new MCPH1 mutation (c.348del) and the clinical features of autosomal recessive primary microcephaly (MCPH), contributing to a broader spectrum related to these pathologies. To our knowledge, this is the first prenatal diagnosis of MCPH due to a novel MCPH1 mutation.

Common structural features characterize interstitial intrachromosomal Xp and 18q triplications.

Rare intrachromosomal triplications producing partial tetrasomies have been reported for a number of chromosomes. A detailed molecular characterization, necessary to define the mechanism of their formation, has so far been lacking. We report on the detailed clinical, cytogenetic, and molecular characterization of two triplications, one de novo involving chromosome 18q, the other familial on chromosome Xp. The clinical phenotype of the patient with 18q triplication, very likely due to overexpression of one or more of the genes in the region, consists mainly of facial dysmorphisms and developmental delay. The familial Xp triplication does not cause an increase in the number of copies of any gene and is almost certainly a polymorphism. The rearrangements are actually complex duplications/triplications. In both patients, their proximal breakpoints are located within complex segmental duplications, one containing the VCX gene cluster on chromosome Xp, the other the TCEB3 genes on chromosome 18q. A proximal duplicated region is also present in both patients. All junctions we analyzed were formed by non-homologous end joining (NHEJ). The structural features shared between our patients suggest the involvement of a common mechanism in the genesis of interstitial intrachromosomal triplications.

Uterine arteriovenous malformations induced after diagnostic curettage: a systematic review.

PURPOSE: To perform an extensive systematic review to examine all the available literature reporting iatrogenic acquired arteriovenous malformation (AVM) induced after diagnostic curettage and to describe a further case of a 34-year-old woman presenting with acute vaginal bleeding due to AVM induced after uterine curettage for termination of pregnancy. METHODS: We searched the electronic databases: MEDLINE (1950-2011), Embase (1980-2011), Cochrane Library (2004-2011), Cinahl (1981-2011), Popline (2004-2011). RESULTS: Initial search extracted 333 relevant articles. Final assessment resulted to the inclusion of 91 studies, 85 case reports and 6 observational studies. Studies are dated between 1954 and 2011. A metanalysis of the 85 case reports reporting 100 patients was performed. The mean age of the women diagnosed with AVM was 30 ± 9.1 years, range (16-72) years, 96 women were premenopausal (96%) and 4 were postmenopausal (4%). Ultrasound imaging was applied in 86 patients (86%), and ultrasound combined with angiography was performed in 51 patients (51%). Uterine artery embolization (UAE) was the most common treatment option performed in 59 patients (59%). Total abdominal hysterectomy was performed in 29 patients (29%). Spontaneous resolution of AVM occurred in six patients (6%). In 17 patients (17%), recurrence occurred after treatment with UAE. Twenty-four articles reported pregnancies in 27 patients (27%). CONCLUSION: Ultrasound imaging with appropriate knowledge of color Doppler features minimizes the use of inappropriate interventional procedures such as diagnostic curettage. UAE is effective in treatment, and rarely leads to complications.

Prenatal diagnosis of Baraitser - Winter syndrome using exome sequencing: Clinical report and review of literature.

Baraitser - Winter Cerebrofrontofacial Syndrome (BWCFF) is a rare disorder characterized by facial dysmorphism and mental retardation of varying grades. The clinical phenotype of BWCFF indicates variable phenotypic expression involving various congenital malformations such as cardiac, renal and musculoskeletal abnormalities. Nevertheless, the prenatal presentation of BWCFF is rarely described, making prenatal diagnosis challenging. This report describes a prenatal diagnosis of BWCFF syndrome to date; a case of a fetus with intrauterine growth restriction, increased nuchal fold, bilateral hydronerphosis, rocker bottom foot and clubfoot detected on Anomaly Scan is outlined. Molecular karyotype failed to detect any abnormality. Assessment with Next Generation Sequencing was then performed, revealing a heterozygous de novo mutation in ACTB gene setting the diagnosis of BWCFF.

A novel heterozygous mutation in the SLC5A2 gene causing severe glycosuria, mild failure to thrive, and subclinical hypoglycemia.

Highlights A novel heterozygous mutation in the SLC5A2 gene in a 2-year-old girl with severe asymptomatic glycosuria, mild failure to thrive, and subclinical hypoglycemia: Continuous glucose monitoring identified 14% hypoglycemic excursions (< 70 mg/dl), reduced at 1% with 1 g/Kg uncooked cornstarch at bed-time milk and eliminated (0%) adjusting the dose at 1.5 g/Kg, as shown by Flash technology.