Molecular Karyotyping Research Articles

A novel tetra-primer ARMS-PCR approach for the molecular karyotyping of chromosomal inversion 2Ru in the main malaria vectors Anopheles gambiae and Anopheles coluzzii

BackgroundChromosomal inversion polymorphisms have been associated with adaptive behavioral, physiological, morphological and life history traits in the two main Afrotropical malaria vectors, Anopheles coluzzii and Anopheles gambiae. The understanding of the adaptive value of chromosomal inversion systems is constrained by the feasibility of cytological karyotyping. In recent years in silico and molecular approaches have been developed for the genotyping of most widespread inversions (2La, 2Rb and 2Rc). The 2Ru inversion, spanning roughly 8% of chromosome 2R, is commonly polymorphic in West African populations of An. coluzzii and An. gambiae and shows clear increases in frequency with increasing rainfall seasonally and geographically. The aim of this work was to overcome the constraints of currently available cytological and high-throughput molecular assays by developing a simple PCR assay for genotyping the 2Ru inversion in individual specimens of both mosquito species.MethodsWe designed tetra-primer amplification refractory mutation system (ARMS)-PCR assays based on five tag single-nucleotide polymorphisms (SNPs) previously shown to be strongly correlated with 2Ru inversion orientation. The most promising assay was validated against laboratory and field samples of An. coluzzii and An. gambiae karyotyped either cytogenetically or molecularly using a genotyping-in-thousands by sequencing (GT-seq) high-throughput approach that employs targeted sequencing of multiplexed PCR amplicons.ResultsA successful assay was designed based on the tag SNP at position 2R, 31710303, which is highly predictive of the 2Ru genotype. The assay, which requires only one PCR, and no additional post-PCR processing other than electrophoresis, produced a clear banding pattern for 98.5% of the 454 specimens tested, which is a 96.7% agreement with established karyotyping methods. Sequences were obtained for nine of the An. coluzzii specimens manifesting 2Ru genotype discrepancies with GT-seq. Possible sources of these discordances are discussed.ConclusionsThe tetra-primer ARMS-PCR assay represents an accurate, streamlined and cost-effective method for the molecular karyotyping of the 2Ru inversion in An. coluzzii and An. gambiae. Together with approaches already available for the other common polymorphic inversions, 2La, 2Rb and 2Rc, this assay will allow investigations of the adaptive value of the complex set of inversion systems observed in the two major malaria vectors in the Afrotropical region.Graphical

Cytological origination of the first found allotriploid tree peony, Paeonia × lemoinei ‘Oukan’ (AAB), reveled by molecular karyotype comparation

Polyploid breeding is one of the most important approaches to improve the traits of cultivated plants, but there has been no feasible method to get polyploid tree peony. In this study, we revealed a sexual triploidization approach from a diploid intersubsectional hybrid tree peony, Paeonia × lemoinei ‘High Noon’, to an allotriploid one, P. × lemoinei ‘Oukan’, by accurate karyotyping based on genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH). The ancestor genomes from P. suffruticosa and P. delavayi, which were defined as A-genome and B-genome respectively, were clearly distinguished by GISH in ‘High Noon’ and ‘Oukan’. Nonhomologous chromosomes were successfully recognized by means of 5S and 45S rDNA FISH. Karyotype comparation based on GISH and FISH indicated that the B-genome and one of the two A-genomes in ‘Oukan’ (2n=3x=15, AAB) were highly consistent to the corresponding genomes in ‘High Noon’ (2n=2x=10, AB), implying the triploid origination via 2n gametes produced by first division restitution (FDR). In addition, it was demonstrated for the first time that the dual in series sites of 5S rDNA located on the short arm of chromosome 3 in both A and B-genomes. Besides the familiar strong 45S rDNA signals observed at terminal region of short arms, single weak 45S rDNA signal was newly detected at terminal region in the short arm of certain chromosome 1 in A-genome, and at interstitial-distal region in the long arm of chromosome 5 in both genomes. These findings provide a proof and theoretical support for tree peony polyploid breeding, and an accurate karyotyping method for genetic research of plants in Paeonia.

Molecular Data and Karyotype Revealed Two Distinct Species of Domesticated Water Buffaloes in the Philippines

The six species of the genus Bubalus include the lowland and mountain anoa, Asian wild buffalo, tamaraw, swamp buffalo, and riverine buffalo. Few studies were conducted on the matrilineal phylogeny and genetic diversity of Bubalus species. In addition, there is controversy regarding the identity of the two domesticated water buffaloes in the Philippines – the introduced riverine and the native swamp buffalo. Thus, this study aimed to determine the genetic distance and phylogenetic relationship of Bubalus species using the mitochondrial cytochrome b (cytb) variation and to re-evaluate the taxonomic species designation of Bubalus bubalis. A total of499 Philippine cytb sequences from this study (n = 179), as well as other Asian countries (n = 319)and Syncerus caffer (n = 1), from NCBI were included in the analysis. The highest interspecies genetic distance (d) (0.040) was between the tamaraw and lowland anoa, whereas the lowest genetic distance (0.020) was between mountain and lowland anoa. Moreover, the phylogenetic tree indicated 52 haplotypes that delineated three groups, including lowland anoa, mountain anoa, and tamaraw with two domesticated buffaloes. The latter group further separated into three species – tamaraw, riverine, and swamp buffaloes. The analyses of genetic distance,phylogeny, and median-joining network structure based on cytb confirmed that the swamp buffaloes from Occidental Mindoro and South Cotabato, Philippines belong to maternal lineage B. Karyotype analysis consistently confirms that riverine buffaloes possess 50 chromosomes, whereas swamp buffaloes have 48 chromosomes, aligning with previous findings. Moreover, the swamp and riverine buffaloes appear to be distinct species, with the swamp buffalo having a closer affinity to the tamaraw than to the riverine buffalo. We, therefore, propose to revive the species assignment of the Bubalus kerabau Fitzinger, 1860 as a distinct species to the swamp buffalo. Furthermore, a common maternal ancestry was confirmed between the tamaraw and two domesticated buffaloes – the swamp and riverine. Research findings provided valuable information on understanding and monitoring the matrilineal genetic diversity of the genus Bubalus toward conservation and management.

CHALLENGES FOR CHROMOSOME ANALYSIS IN PREGNANCY LOSS: LESSONS LEARNED FROM 1208 SAMPLE EXPERIENCE

Objective: Previous studies have shown that half of the spontaneous abortions were associated with fetal chromosomal abnormalities, however it is not always possible to reveal the reasons of pregnancy loss. The aim of the current study was to investigate the frequency of chromosome abnormalities and culture failure rates of pregnancy loss and compare the results with similar studies in the literature.
 
 Material and Methods: The karyotype analysis results of 1208 abortion materials which were obtained from long-term cultures of chorionic villus samples of the patients who were admitted to the Haseki Training and Research Hospital Genetic Diagnosis Center between August 2016 and February 2021, were evaluated retrospectively.
 
 Results: No results were obtained due to culture failure in approximately half of the materials. Numerical anomalies were observed in 87% (116) of abnormal karyotypes that consist of trisomy, monosomy X and triploidy. Trisomies were the most common anomaly. While the frequency of trisomy was significantly higher in the older age group (≥35 years) (p=0.001), the frequency of monosomy X and triploidy were higher in the younger age group. Chromosomal changes whose frequencies were not affected by maternal age were structural chromosomal abnormalities and tetraploidies.
 
 Conclusion: Since the developing new Technologies are still not affordable enough and their widespread use is limited. As a result, current approaches have indicated that chromosome analysis is still a necessary and useful method. It is thought that detecting the chromosomal anomaly that led to abortion facilitates multidisciplinary patient management and enables to provide more accurate and comprehensive genetic counseling. In cases where the chromosome analysis test is not informative, the application of DNA-based tests such as Quantitative Fluorescence PCR (QF-PCR) and molecular karyotyping may help the diagnosis.

Giant uterine fibroids with chromosome 22 monosomy. A clinical case

We present a clinical case of giant uterine fibroids in this research, with the peculiarity of surgical treatment and the course of the postoperative period described. A series of genetic studies specific to uterine fibroids was performed, namely, mutations in the MED12 gene, overexpression of the HMGA2 gene, and chromosomal imbalance. We did not detect mutations of exon 2 of the MED12 gene and an increase in the expression of the HMGA2 gene in the patients myomatous node sample. The molecular karyotype arr(22)1 (chromosome 22 monosomy) was established by comparative genomic hybridization in the tissue of giant uterine fibroids.

O-060 Single-cell DNA sequencing reveals that current bulk DNA sequencing methods lead to an underestimation of chromosomal mosaicism in human blastocysts

Abstract Study question What is the incidence of chromosomal mosaicism in trophectoderm and inner cell mass from good quality human blastocysts after NGS-based single-cell molecular karyotyping? Summary answer Single-cell analysis showed that almost all human blastocysts are mosaic, involving low level mosaicism and/or abnormal cells resulting from reciprocal error events. What is known already Chromosome segregation in early human embryos is considered to be error prone. While meiotic errors affect all cells within embryos, mitotic errors lead to chromosomal mosaicism, the presence of cytogenetically different cells within an embryo. The reported incidence of mosaicism in blastocysts after bulk DNA sequencing of multicellular trophectoderm (TE) biopsies performed for preimplantation genetic testing for aneuploidy (PGT-A) varies between 2-19%. However, bulk DNA analysis can only assess net average chromosome gains or losses with a detection limit of 20-30%, and it makes distinguishing true mosaicism from technical artefact problematic. Study design, size, duration Observational study in human good quality surplus embryos which were donated for research purposes (CCMO, NL82597.000.22). The embryos were thawed and cultured until the blastocyst stage. From the blastocysts with at least a morphology grade 3BB, the ICM was dissociated from the TE. From 55 embryos, both samples were successfully disaggregated into single cells and manually placed in 384 well plates. For the cytogenetic analysis, a validated method for single-cell molecular karyotyping was used (scKaryo-seq). Participants/materials, setting, methods Embryos with at least two cytogenetically different cells were considered mosaic. To investigate if bulk DNA sequencing would have detected this mosaicism, we performed an in-silico reanalysis on our single-cell data. For each embryo, TE cells with the same mitotic abnormality were quantified. Next, we determined the number of mosaic embryos in which these abnormalities were present in at least 20% of TE cells, as a cut-off for what PGT-A methods are expected to detect. Main results and the role of chance On average 42% of the total number of cells that could be isolated per embryo were successfully karyotyped, giving a total of 1057 karyotyped cells (522 normal, 535 abnormal) from 55 embryos. Six embryos (11%) were normal, four (7%) were uniformly abnormal and 45 (82%) were mosaic. From these, 14 (26%) embryos were aneuploid mosaic with cytogenetically different abnormal cells and 31 (56%) were diploid-aneuploid mosaic with normal and abnormal cells. Here cytogenetically different abnormal cells were also frequently observed, with products of reciprocal events detected in 20 embryos. The in-silico reanalysis was performed on 38 embryos with a mosaic TE. It predicted that only 11% of the mitotic abnormalities observed in TE cells through scKaryo-seq would have been detected by bulk DNA sequencing. In 19 out of 38 embryos at least one mitotic abnormality affected more than 20% of the TE cells, meaning that only 50% of the embryos would have been recognized as mosaic with bulk DNA analysis. Bulk DNA sequencing methods used for PGT-A lead to an underestimation of mosaicism, since low-level mosaicism that affects a few cells within an embryo and products of reciprocal events without a net gain or loss remain undetected. Limitations, reasons for caution Isolation and cytogenetic analysis of viable single cells at the blastocyst stage is technically challenging and only 42% of the cells per embryo could be successfully karyotyped. Furthermore, it is unknown to what extent in vitro culture conditions and the freezing-thawing process influenced our findings. Wider implications of the findings These single cell observations support the notion that mosaicism is a common biological phenomenon in human blastocysts. Any selective mechanism eliminating embryos or cells with chromosomal abnormalities is still not fully active at this stage. The underestimation of mosaicism by bulk DNA analysis has potential implications for current PGT-A practices Trial registration number not applicable

Terminal microdeletion of chromosome 18 in a Malaysian boy characterized with few features of typical 18q- deletion syndrome: a case report

BackgroundThe 18q- deletion syndrome is a rare congenital chromosomal disorder caused by a partial deletion of the long arm of chromosome 18. The diagnosis of a patient with this syndrome relies on the family medical history, physical examination, developmental assessment, and cytogenetic findings. However, the phenotype of patients with 18q- deletion syndrome can be highly variable, ranging from almost normal to severe malformations and intellectual disability, and normal cytogenetic findings are common, thus complicating the diagnosis. Interestingly, only few characteristic features of typical 18q- deletion syndrome were found in the patient, despite sharing the same critical region. To our knowledge, this is the first report of a Malaysian individual with 18q- terminal microdeletion diagnosed with microarray-based technology.Case presentationHere we report a 16-year-old Malaysian Chinese boy, a product of a non-consanguineous marriage, who presented with intellectual disability, facial dysmorphism, high arched palate, congenital talipes equinovarus (clubfoot), congenital scoliosis, congenital heart defect, and behavioral problems. A routine chromosome analysis on 20 metaphase cells showed a normal 46, XY G-banded karyotype. Array-based comparative genomic hybridization was performed using a commercially available 244 K 60-mer oligonucleotide microarray slide according to the manufacturer’s protocol. This platform allows genome-wide survey and molecular profiling of genomic aberrations with an average resolution of about 10 kB. In addition, multiplex ligation-dependent probe amplification analysis was carried out using SALSA MLPA kit P320 Telomere-13 to confirm the array-based comparative genomic hybridization finding. Array-based comparative genomic hybridization analysis revealed a 7.3 MB terminal deletion involving chromosome band 18q22.3-qter. This finding was confirmed by multiplex ligation-dependent probe amplification, where a deletion of ten probes mapping to the 18q22.3-q23 region was detected, and further multiplex ligation-dependent probe amplification analysis on his parents showed the deletion to be de novo.ConclusionThe findings from this study expand the phenotypic spectrum of the 18q- deletion syndrome by presenting a variation of typical 18q- deletion syndrome features to the literature. In addition, this case report demonstrated the ability of the molecular karyotyping method, such as array-based comparative genomic hybridization, to assist in the diagnosis of cases with a highly variable phenotype and variable aberrations, such as 18q- deletion syndrome.

CRISPR/Cas9 editing of transformer2 gene of the Oriental fruit Fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) leads to intersex phenotype

The Oriental fruit fly, Bactrocera dorsalis is a serious, highly invasive pest of fruits affecting global trade. Areawide management of B. dorsalis by release of sterile males obtained through irradiation suffers from the disadvantage of somatic mutations. In this regard, insect pest management in the post genome editing era poised for producing precise mutations based on CRISPR/Cas for example precision guided sterile insect technique and gene drive. Development of these technologies depend on the genes in sex determination pathway and spermatogenesis in target species. In the sex determination pathway of B. dorsalis, transformer (tra & tra2) are involved in female specific splicing of double sex (dsx). CRISPR/Cas9 mediated loss-of-function of tra has been shown to influence sex determination while it is lacking in tra2. In the present study we have edited transformer2 gene through embryonic microinjection of CRISPR/Cas9 ribonucleprotein (Cas9+sgRNA) targeting the sixth exon. Among the emergent G0 individuals, two showed an intersex phenotype, with a male-specific dorsal bristles in the third tergite on the left side of the abdomen and a degenerate ovipositor. The third individual manifested an unique phenotype, with a complete absence of the male specific dorsal bristles but a complete degenerate ovipositor. Sequencing results revealed both addition and deletions in all the three intersexes. Additionally, molecular karyotyping of these individuals, through Maleness on Y (MoY) PCR revealed a XX karyotype for all of them. Hence, we have shown that editing of the transformer2 locus in B. dorsalis interferes with the normal sex determination.

Added value of molecular karyotype in childhood acute lymphoblastic leukemia.

Thanks to an improved therapeutic regimen in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL), 5 year-overall survival now exceeds 90%. Unfortunately, the 25% of children who relapse have an initial poor prognosis, potentially driven by pre-existing or emerging molecular anomalies. The latter are initially and essentially identified by cytogenetics. However, some subtle alterations are not visible through karyotyping. Single nucleotide polymorphisms (SNP) array is an alternative way of chromosomal analysis allowing for a more in-depth evaluation of chromosomal modifications such as the assessment of copy number alterations (CNA) and loss of heterozygosity (LOH). This method was applied here in retrospective diagnosis/relapse paired samples from seven children with BCP-ALL and in a prospective cohort of 38 newly diagnosed childhood cases. In the matched study, compared to the initial karyotype, SNP array analysis reclassified two patients as poor prognosis cases. Modulation during relapse was seen for 4 CNA and 0.9 LOH. In the prospective study, SNP reclassified the 10 patients with intermediate karyotype as 7 good prognosis and 3 poor prognosis. Ultimately, in all the children tested, SNP array allowed to identify additional anomalies compared to conventional karyotype, refine its prognostic value and identify some druggable anomalies that could be used for precision medicine. Overall, the anomalies detected could be segregated in four groups respectively involved in B-cell development, cell proliferation, transcription and molecular pathways. SNP therefore appears to be a method of choice in the integrated diagnosis of BCP ALL, especially for patients initially classified as intermediate prognosis. This complementary method of both cytogenetics and high throughput sequencing allows to obtain further classified information and can be useful in case of failure of these techniques.

Triploid and aneuploid hybrids obtained from hybridization between Eriobotrya japonica and E. cavaleriei

A short ripening stage, multiple large seeds per fruit, and anthracnose disease seriously restrict the loquat (Eriobotrya japonica) industry. To obtain breeding germplasm of loquat with multiple ideal traits, a wild Eriobotrya species, E. cavaleriei (2n=2x=34), which flowers in late spring and early summer and whose fruits ripen in autumn, was used as the male parent to produce triploid plants from crosses with loquat tetraploid (2n=4x=68) lines (EjK474, EjB433 and EjB456). Fifteen progenies were obtained from three hybridizations, and 13 plants were identified as hybrids according to insertion-deletion (InDel) markers. All 13 hybrids were roughly identified as triploids by flow cytometry. Therein, 4 plants were identified as aneuploids with decreased or increased chromosome numbers based on sequencing depth according to reduced-representation genome sequencing. The sequencing depth on some chromosomes of these 4 hybrids was approximately 2/3 times or 1.41 times the average depth of all detected InDel loci. Frequencies of the loquat parent-specific alleles on increased or decreased chromosomes were approximately 50% or 75%. This verified that increased or decreased alleles in the 4 hybrids were all from tetraploid parents. The fruit flesh color genotypes of all hybrids were detected; there were two red-flesh alleles and one white-flesh allele in all hybrids. Leaves of E. cavaleriei were highly resistant to anthracnose in an in vitro assay, and the leaves of loquat B433 were sensitive. Disease spot diameters on the leaves of hybrids were significantly smaller (p < 0.01) than those of B433 after infection by spores of C. gloeosporioides. Therefore, the resistance of the hybrids was greater than that of the female parent B433. All these results showed that allotriploids can be obtained via hybridization between loquat tetraploids and E. cavaleriei, with some aneuploids as secondary products. Different flowering phases and fruit ripening stages, seedlessness and resistance to anthracnose might be combined in allotriploids. This study verified that resequencing can be used to identify the molecular karyotype of interspecific hybrids.

THE GENETIC APPROACH TO STILLBIRTH: A SYSTEMATIC REVIEW.

An unexplained stillbirth is defined as stillbirth with no known cause after exclusion of common causes, including obstetric complications, infections, placental insufficiency or abruption, umbilical cord complications, and congenital abnormalities with or without known genetic cause. More than 60 % of stillbirth cases remain unexplained. The aim of this systematic review was to investigate the known genetic causes for unexplained stillbirth cases and to evaluate the current position and future directions for the use of genetic and genomic testing in expanding the knowledge in this field. A systematic search through several databases was performed using the keywords genetics and stillbirths in human. Different methods to detect various types of causal genetic aberrations have been used in the past decades, from standard karyotyping to novel methods such as chromosomal microarray analysis and next generation sequencing technologies. Apart from common chromosomal aneuploidies, a promising hypothesis about genetic causes included genes related to cardiomyopathies and channelopathies. However, these were tested in the research settings, since molecular karyotyping is currently the standard approach in the routine evaluation of genetic causes of stillbirth. Hereby we provide evidence that expanding knowledge using novel genetic and genomic testing might discover new genetic causes of unexplained stillbirth. This article is protected by copyright. All rights reserved.

The genetic landscape and clinical implication of pediatric Moyamoya angiopathy in an international cohort

Pediatric Moyamoya Angiopathy (MMA) is a progressive intracranial occlusive arteriopathy that represents a leading cause of transient ischemic attacks and strokes in childhood. Despite this, up to now no large, exclusively pediatric MMA cohort has been subjected to systematic genetic investigation. In this study, we performed molecular karyotyping, exome sequencing and automated structural assessment of missense variants on a series of 88 pediatric MMA patients and correlated genetic, angiographic and clinical (stroke burden) findings. The two largest subgroups in our cohort consisted of RNF213 and neurofibromatosis type 1 (NF1) patients. While deleterious RNF213 variants were associated with a severe MMA clinical course with early symptom onset, frequent posterior cerebral artery involvement and higher stroke rates in multiple territories, NF1 patients had a similar infarct burden compared to non-NF1 individuals and were often diagnosed incidentally during routine MRIs. Additionally, we found that MMA-associated RNF213 variants have lower predicted functional impact compared to those associated with aortic disease. We also raise the question of MMA as a feature of recurrent as well as rare chromosomal imbalances and further support the possible association of MMA with STAT3 deficiency. In conclusion, we provide a comprehensive characterization at the genetic and clinical level of a large exclusively pediatric MMA population. Due to the clinical differences found across genetic subgroups, we propose genetic testing for risk stratification as part of the routine assessment of pediatric MMA patients.

Expanding the phenotype of 12q21 deletions: A role of BTG1 in speech development?

We report on a female individual with feeding difficulties, constipation, poor overall growth, periventricular lesions resembling gliosis in brain MRI, recurrent otitis media with palsy of facial nerve, distinct facial features, and pronounced delay in speech development. The latter was the most prominent feature. Molecular karyotyping revealed a heterozygous de novo deletion of 4.353 Mb at chromosome 12q21.33q22. This report expands the number of described individuals with heterozygous deletions at 12q21.33, their clinical spectrum and highlights the clinical variability, even in individuals with deletion of the same genes. Furthermore, our findings indicate a role of BTG1 (OMIM *109580) in speech development.

A novel colony-stimulating factor 1 (CSF1) translocation involving human endogenous retroviral element in a tenosynovial giant cell tumor.

Tenosynovial giant cell tumors (TSGCTs) are rare tumors arising in tendons or the synoviae of joints and bursae. The localized type is benign while the diffuse type shows expansive growth leading to greater morbidity and is therefore considered locally aggressive. Typical recurrent chromosomal aberrations are found in the majority of TSCGT and the CSF1 gene is frequently involved. In this article, we describe a newly identified gene fusion mediated by an inversion in a case of diffuse TSGCT. Multicolor-fluorescence in situ hybridization (FISH) molecular karyotyping identified a pericentric inversion of chromosome 1 in 7 out of 17 analyzed cells 46,XX,inv(1)(p13.3q24.3) [7]/46,XX [10], and with interphase FISH the involvement the CSF1 locus was detected. After performing transcriptome sequencing analysis for fusion detection, only one out of five fusion gene algorithms detected a fusion involving the CSF1 gene product. The resulting chimera fuses a sequence from a human endogenous retrovirus (HERV) gene to CSF1 Exon 6 on chromosome 1, abrogating the regulatory element of the 3' untranslated region of the CSF1 gene. This new translocation involving Exon 6 of the CSF1 gene fused to 1q24.1, supports the hypothesis that a mutated CSF1 protein is likely to play a vital role in the pathogenesis of TSGCT. The role of the HERV partner identified as a translocation partner, however, remains unclear. Our data add to the complexity of involved translocation partners in TSGCT and point to the potential difficulty of identifying fusion partners in tumor diagnostics using transcriptome sequencing when HERV or other repeat elements are involved.

Varijacije u broju kopija na hromozomu 15 detektovane molekularnom kariotipizacijom kod pacijenata sa razvojnim kašnjenjem i urođenim anomalijama

Introduction: Global developmental delay (GDD) and congenital anomalies represent a heterogeneous group of medical conditions that may have a known genetic etiology. Molecular karyotyping is the gold standard for detecting copy number variations (CNV), and the first-line test in patients with GDD and congenital anomalies, with an average diagnostic yield of 15%. Chromosome 15 (C15) is one of the chromosomes on which CNV occurs most frequently. Aim: To analyze all detected (significant) CNVs on C15 in patients with GKR and/or congenital anomalies, estimate their share in the overall CNV detection rate of different pathogenicity classes, and present several illustrative cases. Material and methods: In the total sample of 350 patients analyzed by molecular karyotyping technique, 92 with detected significant CNV were singled out. All patients with variants on C15 were then analyzed and further classified according to type, size, and clinical significance. Results: In 11 patients, at least one significant CNV was detected on chromosome 15, which is 3.15% of the total sample and 11.96% of a sample of patients with significant CNV of any localization. In 72.7% cases, CNV was described as pathogenic or likely pathogenic and in 27.3% as a variant of unknown significance. In the total detection rate of csCNV from all chromosomes 15.4%, the percentage of variations from C15 was 17.2%. Conclusion: The detection rate of csCNVs on C15 in the diagnostic yield of the molecular karyotypisation of patients with GDD and congenital anomalies is 17.2%, which confirms that they make up a significant portion of the GDD etiology.

Expanding the clinical and molecular features of trichorhino- phalangeal syndrome with a novel variant.

Tricho-rhino-phalangeal syndrome (TRPS) is a rare, autosomal dominant disorder characterized by typical craniofacial features, ectodermal and skeletal findings. TRPS type 1 (TRPS1) is caused by pathogenic variations in the TRPS1 gene, which relates to the vast majority of cases. TRPS type 2 (TRPS2) is a contiguous gene deletion syndrome involving loss of functional copies of the TRPS1, RAD21, and EXT1. Herein, we reported the clinical and genetic spectrum of seven TRPS patients with a novel variant. We also reviewed the musculoskeletal and radiological findings in the literature. Seven Turkish patients (three female, four male) from five unrelated families aged between 7 to 48 years were evaluated. The clinical diagnosis was confirmed by either molecular karyotyping or TRPS1 sequencing analysis via next-generation sequencing. Both TRPS1 and TRPS2 patients had some common distinctive facial features and skeletal findings. All patients had a bulbous nose with hypoplastic alae nasi, brachydactyly, short metacarpals and phalanges in variable stages. Low bone mineral density (BMD) was identified in two TRPS2 family members presenting with bone fracture, and growth hormone deficiency was detected in two patients. Skeletal X-ray imaging revealed cone-shaped epiphysis of the phalanges in all, and multiple exostoses were present in three patients. Cerebral hamartoma, menometrorrhagia and long bone cysts were among the new/rare conditions. Three pathogenic variants in TRPS1 were identified in four patients from three families, including a frameshift (c.2445dup, p.Ser816GlufsTer28), one missense (c.2762G > A), and a novel splice site variant (c.2700+3A > G). We also reported a familial inheritance in TRPS2 which is known to be very rare. Our study contributes to the clinical and genetic spectrum of patients with TRPS while also providing a review by comparing with previous cohort studies.

Incidental Detection of a Chromosomal Aberration by Array-CGH in an Early Prenatal Diagnosis for Monogenic Disease on Coelomic Fluid.

Turner syndrome is a rare genetic condition in which a female is partly or completely missing an X chromosome. Signs and symptoms vary among those affected. In fetuses that survive at birth and without congenital malformations, the prognosis is usually positive, but it has high lethality in utero, especially in the first trimester of pregnancy. We report a case of monosomy X detected during a prenatal diagnosis for beta thalassemia on coelomic fluid (CF) at the VIII week of gestation. Beta globin gene analysis, whole genome amplification (WGA), quantitative fluorescent PCR and array comparative genomic hybridization (array-CGH) were performed on DNA extracted from CF. A monoallelic pattern of all Short Tandem Repeats mapped on the X chromosome was found and array-CGH performed on WGA from a few fetal erythroblasts confirmed monosomy X. This report underlines the importance of an early prenatal diagnosis and the countless potentialities of array-CGH that could make definition of molecular karyotype possible from a few fetal cells, unlike conventional cytogenetic techniques that require a greater cellular content. This is the first report of a molecular karyotype obtained from two cells selected by micromanipulation of CF and defined at such an early gestational age.

First cytogenomic characterization of murine testis tumor cell line MLTC-1

The cell line MLTC-1 was established in 1982 as a transplantable Leydig cell tumor from a C57BL/6 mouse. The cell line has already been applied in &amp;gt;100 studies: still, the only information about its genetic content is given in the first description: MLTC-1 initially had a polyploid karyotype. Here, a molecular karyotyping and multicolor banding-based molecular cytogenetic study was done to provide the first chromosomal/ (molecular) cytogenetic characterization of MLTC-1. A hexaploid karyotype with 72 to 105 chromosomes was hereby characterized. Besides polyploidy, unbalanced two- and three-way translocations, dicentrics and one neocentric derivative were identified. Also, no Y-chromosome could be detected in this clearly male derived cell line. Overall, a completely unbalanced genome is present in MLTC-1 with ~20 regions being subject to copy number losses or gains. After translating these imbalances into the human genome in a standardized way, a 40% match of imbalances with human Leydig cell tumors was evident; however, about the same rate of concordance was detectable for human spermatocytic seminomas and non-seminomas as well as testicular germ cell tumor. Accordingly, MLTC-1 is better suited as an advanced testicular germ cell tumor model in general, rather than specifically for human Leydig cell tumors.

Olecular cytogenetic and cytopostgenomic analysis of the human genome

Despite the achievements of human genomics, comprehensive genome analysis, including acquiring the knowledge about intercellular and interindividual variations at (sub)chromosomal/ cytogenomic level, remains a difficult task. This basically results from a lack of heuristic algorithms for uncovering (cyto)genomic and/or somatic genome variations and the functional outcomes. However, current developments in molecular cytogenetics and “cytopostgenomics” may offer a solution of the problem. The aim of the study: To present a heuristic algorithm for molecular cytogenetic and cytopostgenomic analysis of the human genome to uncover mechanisms of genetic (brain/neurodevelopmental) diseases. Materials and methods: Data on cytogenetic and (cyto)genomic variations (chromosome abnormalities, chromosome/genome instability, copy number variation (CNV) etc.) addressed by original molecular cytogenetic techniques and processed by original bioinformatic (cytopostgenomic) methods were used to develop the algorithm. Karyotyping was performed in 8556 individuals. FISH analysis was applied when required (cases of somatic mosaicism/ chromosome instability). Molecular karyotyping by SNP-array was performed in 600 (~7%) cases. Results: Using our long-term experience of studying chromosomal and genomic variations/instability in neurodevelopmental disorders as well as original developments in (cyto) genomic data processing, we managed to present a heuristic algorithm for molecular cytogenetic and cytopostgenomic analysis of the human genome to uncover mechanisms for brain diseases. Estimated efficiency of the algorithm was established to achieve 84%. Analyzing the dynamics of applying cytogenetic and cytogenomic techniques throughout ~35 years of our diagnostic research we found that the diagnostic efficiency had been increasing from ~7% (exclusive diagnosis by karyotyping) to more than 80% (molecular cytogenetic and cytopostgenomic analysis). Conclusion: Here, we propose a heuristic algorithm for molecular cytogenetic and cytopostgenomic analysis of the human genome to uncover mechanisms for genetic diseases. The efficiency and ability to uncover mechanisms of chromosome instability allows us to conclude that the algorithm may be highly competitive for basic and diagnostic genomic/cyto(post)genomic research.

Possibilities and Limitations of CNV Interpretation Software and Algorithms in Homo Sapiens

Background: Technical advances and cost reduction have allowed for the worldwide popularity of array platforms. Otherwise called “molecular karyotyping”, it yields a large amount of CNV data, which is useless without interpretation. Objective: This study aims to review existing CNV interpretation software and algorithms to reveal their possibilities and limitations. Results: Open and user-friendly CNV interpretation software is limited to several options, which mostly do not allow for cross-interpretation. Many algorithms are generally based on the Database of Genomic Variants, CNV size, inheritance data, and disease databases, which currently seem insufficient. Conclusion: The analysis of CNV interpretation software and algorithms resulted in a conclusion that it is necessary to expand the existing algorithms of CNV interpretation and at least include pathway and expression data. A user-friendly freely available CNV interpretation software, based on the expanded algorithms, is yet to be created.