Kabızlık ve Üfürümle Tespit Edilen Williams-Beuren Sendromu

Williams-Beuren Syndrome Detected with Constipation and Murmur Williams-Beuren syndrome (WBS) is a rare disease that occurs as a result of microdeletion of 11.23 of the long arm of chromosome 7, with a frequency of 1/20.000-30.000. Typical facial appearance, mental retardation, various congenital cardiovascular anomalies and endocrinological disorders may accompany this syndrome. In cases suspected as a result of clinical and laboratory findings, the diagnosis is made by showing the deletion of the mentioned region using the fluorescent in situ hybridization (FISH) method. We detected WBS in a 17-month-old male patient who presented with chronic constipation and had peripheral pulmonary stenosis in echocardiography performed with accompanying clinical findings, and aimed to emphasize the importance of multidimensional evaluation and early diagnosis. Keywords: Congenital heart disease, pulmonary stenosis, microdeletion syndromes, constipation, Williams-Beuren syndrome

Invivo and systematic analysis of random multigenic deletions associated with human diseases during epithelial morphogenesis in Drosophila

Random loss of multigenic loci on chromosomes, a crucial drive for evolution, occurs frequently in all living organisms. Analysis of such chromosomal disruption and understanding the consequences of their impact on the growth and development of multicellular organisms is challenging. In this report, we have addressed this issue using invivo mosaic analysis of deficiency lines in Drosophila. Genes on fly deficiency lines were compared with human orthologs for their implications in disease development during cytoskeletal processes and epithelial morphogenesis. The cytoskeletal phenotypes from the fly has been utilized to predict the function of human orthologs. In addition, as these Drosophila deficiency lines are equivalent to human microdeletions, based on the clonal behaviour and phenotypes generated, a systematic analysis has been carried out to establish the critical loci that correspond to Microdeletion Syndromes and Mendelian Disorders in humans. Further we have drawn the synteny that exists between these chromosomes and have identified critical region corresponding to defects. A few potential candidates that might have an implication in epithelial morphogenesis are also identified.

Genome mapping resolves structural variation within segmental duplications associated with microdeletion/microduplication syndromes

Segmental duplications (SDs) are a class of long, repetitive DNA elements whose paralogs share a high level of sequence similarity with each other. SDs mediate chromosomal rearrangements that lead to structural variation in the general population as well as genomic disorders associated with multiple congenital anomalies, including the 7q11.23 (Williams-Beuren Syndrome, WBS), 15q13.3, and 16p12.2 microdeletion syndromes. These three genomic regions, and the SDs within them, have been previously analyzed in a small number of individuals. However, population-level studies have been lacking because most techniques used for analyzing these complex regions are both labor- and cost-intensive. In this study, we present a high-throughput technique to genotype complex structural variation using a single molecule, long-range optical mapping approach. We identified novel structural variants (SVs) at 7q11.23, 15q13.3 and 16p12.2 using optical mapping data from 154 phenotypically normal individuals from 26 populations comprising 5 super-populations. We detected several novel SVs for each locus, some of which had significantly different prevalence between populations. Additionally, we refined the microdeletion breakpoints located within complex SDs in two patients with WBS, one patient with 15q13.3, and one patient with 16p12.2 microdeletion syndromes. The population-level data presented here highlights the extreme diversity of large and complex SVs within SD-containing regions. The approach we outline will greatly facilitate the investigation of the role of inter-SD structural variation as a driver of chromosomal rearrangements and genomic disorders.

Delineation of Clinical Manifestations of the Inherited Xq24 Microdeletion Segregating with sXCI in Mothers: Two Novel Cases with Distinct Phenotypes Ranging from UBE2A Deficiency Syndrome to Recurrent Pregnancy Loss

Chromosomal microdeletion syndromes present with a wide spectrum of clinical phenotypes that depend on the size and gene content of the affected region. In a healthy carrier, epigenetic mechanisms may compensate for the same microdeletion, which may segregate through several generations without any clinical symptoms until the epigenetic modifications no longer function. We report 2 novel cases of Xq24 microdeletions inherited from mothers with extremely skewed X-chromosome inactivation (sXCI). The first case is a boy presenting with X-linked mental retardation, Nascimento type, due to a 168-kb Xq24 microdeletion involving 5 genes (CXorf56, UBE2A, NKRF, SEPT6, and MIR766) inherited from a healthy mother and grandmother with sXCI. In the second family, the presence of a 239-kb Xq24 microdeletion involving 3 additional genes (SLC25A43, SLC25A5-AS1, and SLC25A5) was detected in a woman with sXCI and a history of recurrent pregnancy loss with a maternal family history without reproductive wastages or products of conception. These cases provide evidence that women with an Xq24 microdeletion and sXCI may be at risk for having a child with intellectual disability or for experiencing a pregnancy loss due to the ontogenetic pleiotropy of a chromosomal microdeletion and its incomplete penetrance modified by sXCI.

Targeted capture enrichment followed by NGS: development and validation of a single comprehensive NIPT for chromosomal aneuploidies, microdeletion syndromes and monogenic diseases

Background Non-invasive prenatal testing (NIPT) has been widely adopted for the detection of fetal aneuploidies and microdeletion syndromes, nevertheless, limited clinical utilization has been reported for the non-invasive prenatal screening of monogenic diseases. In this study, we present the development and validation of a single comprehensive NIPT for prenatal screening of chromosomal aneuploidies, microdeletions and 50 autosomal recessive disorders associated with severe or moderate clinical phenotype. Results We employed a targeted capture enrichment technology powered by custom TArget Capture Sequences (TACS) and multi-engine bioinformatics analysis pipeline to develop and validate a novel NIPT test. This test was validated using 2033 cell-fee DNA (cfDNA) samples from maternal plasma of pregnant women referred for NIPT and paternal genomic DNA. Additionally, 200 amniotic fluid and CVS samples were used for validation purposes. All NIPT samples were correctly classified exhibiting 100% sensitivity (CI 89.7–100%) and 100% specificity (CI 99.8–100%) for chromosomal aneuploidies and microdeletions. Furthermore, 613 targeted causative mutations, of which 87 were unique, corresponding to 21 monogenic diseases, were identified. For the validation of the assay for prenatal diagnosis purposes, all aneuploidies, microdeletions and point mutations were correctly detected in all 200 amniotic fluid and CVS samples. Conclusions We present a NIPT for aneuploidies, microdeletions, and monogenic disorders. To our knowledge this is the first time that such a comprehensive NIPT is available for clinical implementation.

Non-invasive prenatal testing by low coverage genomic sequencing: Detection limits of screened chromosomal microdeletions

ObjectiveTo study the detection limits of chromosomal microaberrations in non-invasive prenatal testing with aim for five target microdeletion syndromes, including DiGeorge, Prader-Willi/Angelman, 1p36, Cri-Du-Chat, and Wolf-Hirschhorn syndromes.MethodWe used known cases of pathogenic deletions from ISCA database to specifically define regions critical for the target syndromes. Our approach to detect microdeletions, from whole genome sequencing data, is based on sample normalization and read counting for individual bins. We performed both an in-silico study using artificially created data sets and a laboratory test on mixed DNA samples, with known microdeletions, to assess the sensitivity of prediction for varying fetal fractions, deletion lengths, and sequencing read counts.ResultsThe in-silico study showed sensitivity of 79.3% for 10% fetal fraction with 20M read count, which further increased to 98.4% if we searched only for deletions longer than 3Mb. The test on laboratory-prepared mixed samples was in agreement with in-silico results, while we were able to correctly detect 24 out of 29 control samples.ConclusionOur results suggest that it is possible to incorporate microaberration detection into basic NIPT as part of the offered screening/diagnostics procedure, however, accuracy and reliability depends on several specific factors.What’s already known about this topic?Microdeletion detection accuracy, similarly to most common trisomies detection, was found to be dependent mostly on technical and biological parameters of the test and tested samples, such as coverage of target region, fetal fraction, size and positions of the deletions.What does this study add?Estimation of relevant regions for five chosen microdeletion syndromes. Confirmation and improvement upon previous methods. Systematic evaluation of sensitivity of microdeletion detection with read counts from 10M to 20M.