CHROMOSOMAL POLYMORPHISM IN BULGARIAN PATIENTS WITH REPRODUCTIVE PROBLEMS – ONE GENETIC CENTRE EXPERIENCE

Chromosomal polymorphism is described as normal variants at chromosomal regions with no impact on the phenotype but a possible correlation to infertility and recurrent spontaneous abortions. The aim of this study was to evaluate the effect of the chromosomal polymorphisms involved in families with reproductive failures in the Bulgarian population. Material and methods: A total of 1733 patients with unexplained reproductive failures who visited the Laboratory of Medical Genetics – Varna, Bulgaria, (2004 - 2019) were investigated by conventional cytogenetic analysis GTG and CBG differential banding techniques and analyzed at the resolution 400-550 GTG bands. Results: Chromosomal polymorphisms were found in 173 infertile patients (9,98%). The sex distribution was 6,52% males and 3,46% females. The most frequent finding was inv(9)(qh) (23,7%). The other chromosomal variants, which were found, consisted: 9qh+/- variants (15,1%); polymorphisms on the short arms of the acrocentric chromosomes (21,4%); 16qh+ (12,7%) and 1qh+ (6,9%). Y chromosome polymorphism was found in 27,4% of the males with polymorphisms. Two rare cases of polymorphism involving the centromere regions - 19qcenh+ and 20pcenh+ were also found. Conclusion: There is growing evidence that polymorphisms may have a clinical impact on fertility and could take part in the etiology of RF. In this study, we found a significantly high percentage of polymorphisms (9,98%) among the tested patients, and they were more common among males. The statistical significance of increased incidence of chromosome variations found in our study emphasizes the need for routine evaluation of their role in families with RF in our country.

Hyperdiploid Multiple Myeloma with Novel Complex Structural Chromosome Abnormalities Associated with Poor Prognosis : A Rare Case Report

Hyperdiploid multiple myeloma (MM) is associated with better prognosis and non-hyperdiploid subtype is associated with variable to adverse prognosis based on the nature of karyotype abnormality. Rarely exceptions to this hyperdiploid and non-hyperdiploid divisions do exist in a minority. We report an adult male MM patient who showed hyperdiploid karyotype with few novel complex abnormalities and who showed poor clinical outcome. Conventional cytogenetic analysis carried out in 22 GTG banded metaphases showed 53,Y,der(X)t(X;22)(q27;q11.2),+3,+5,+6,+9,+11,+15,der(17)ins(17;1;3)(q11.2;?;?),der(17)ins(17;1;3)(q11.2;?;?),+19,-22,+mar karyotype pattern in 15 metaphases whereas 7 metaphases showed 46,XY karyotype pattern. Interphase FISH revealed biallelic del(13q14) and del(17p13) but no translocations involving the 14q32 region. Through Spectral karyotyping FISH, the origin of complex abnormalities involving der(17) chromosome, translocation t(X;22), and marker chromosome could be clearly delineated. Although the present case showed hyperdiploid karyotype, he showed an adverse prognosis probably due to the co-existence of high risk and complex abnormalities and expired 5 months after initial diagnosis despite standard treatment given.

Cytogenetic and Array-CGH Characterization of a Simple Case of Reciprocal t(3;10) Translocation Reveals a Hidden Deletion at 5q12

Chromosome deletions, including band 5q12, have rarely been reported and have been associated with a wide range of clinical manifestations, such as postnatal growth retardation, intellectual disability, hyperactivity, nonspecific ocular defects, facial dysmorphism, and epilepsy. In this study, we describe for the first time a child with growth retardation in which we identified a balanced t(3;10) translocation by conventional cytogenetic analysis in addition to an 8.6 Mb 5q12 deletion through array-CGH. Our results show that the phenotypic abnormalities of a case that had been interpreted as “balanced” by conventional cytogenetics are mainly due to a cryptic deletion, highlighting the need for molecular investigation in subjects with an abnormal phenotype before assuming the cause is an apparently simple cytogenetic rearrangement. Finally, we identify PDE4D and PIK3R1 genes as the two major candidates responsible for the clinical features expressed in our patient.

Challenging conventional karyotyping by next-generation karyotyping in 281 intensively treated patients with AML

Although copy number alterations (CNAs) and translocations constitute the backbone of the diagnosis and prognostication of acute myeloid leukemia (AML), techniques used for their assessment in routine diagnostics have not been reconsidered for decades. We used a combination of 2 next-generation sequencing–based techniques to challenge the currently recommended conventional cytogenetic analysis (CCA), comparing the approaches in a series of 281 intensively treated patients with AML. Shallow whole-genome sequencing (sWGS) outperformed CCA in detecting European Leukemia Net (ELN)–defining CNAs and showed that CCA overestimated monosomies and suboptimally reported karyotype complexity. Still, the concordance between CCA and sWGS for all ELN CNA–related criteria was 94%. Moreover, using in silico dilution, we showed that 1 million reads per patient would be enough to accurately assess ELN-defining CNAs. Total genomic loss, defined as a total loss ≥200 Mb by sWGS, was found to be a better marker for genetic complexity and poor prognosis compared with the CCA-based definition of complex karyotype. For fusion detection, the concordance between CCA and whole-transcriptome sequencing (WTS) was 99%. WTS had better sensitivity in identifying inv(16) and KMT2A rearrangements while showing limitations in detecting lowly expressed PML-RARA fusions. Ligation-dependent reverse transcription polymerase chain reaction was used for validation and was shown to be a fast and reliable method for fusion detection. We conclude that a next-generation sequencing–based approach can replace conventional CCA for karyotyping, provided that efforts are made to cover lowly expressed fusion transcripts.

FREQUENCY OF CLINICAL FEATURES AND CYTOGENETIC DEFECTS IN DOWN SYNDROME DIAGNOSED AT AFIP

Objective: To determine the frequency of clinical features and cytogenetic abnormalities in patients of down syndrome and correlation of cytogenetic abnormalities with clinical features. Study Design: Cross sectional study. Place and Duration of Study: Department of Haematology, Armed Forces Institute of Pathology, Rawalpindi, from Feb 2017 to Feb 2018. Methodology: Total 163 patients with clinical suspicion of Down syndrome were selected by non-probability convenient sampling and diagnosis was confirmed by conventional cytogenetic analysis using Giemsa trypsin banding technique. Clinical features were assessed and frequency of different cytogenetic abnormalities were noted. Results: Out of total 163 patients, 96 (59%) were male and 67 (41%) were female. Median age of the patients was 11 months. Trisomy 21 was detected in 158 (96.9%), Robertsonian translocation in 4 (2.4%) and mosaicism in 01 (0.6%) patient. The predominant clinical features observed were slaunted with eyes, epicanthic folds, depressed nasal bridge and protruding tongue. Conclusion: Trisomy 21 is the most common cytogenetic abnormality observed in patients of down syndrome.

A Dual Gender Rare Case with 47,XY, + 18/46,XX Karyotype: Chimera or Mosaic?

Our objective is to report one rare case of dual gender chimerism involving abnormal male trisomy 18 and normal female karyotype. The baby was born full term with birth weight of 1.8 kg, not vigorous with light meconium stained liquor and Apgar score of 51, 85 and 910. Parents are 40 years old and mother is G6P5 + 1. The baby had clinical features of Edwards syndrome, and a blood sample was sent to Human Genome Centre, Universiti Sains Malaysia, Malaysia for cytogenetic analysis. Conventional cytogenetic analysis results showed two distinct sex discordant genetic cell lines XY and XX in 90:10 ratio. The male genetic cell line XY also showed trisomy 18 (47,XY, + 18) consistent with clinical diagnosis of male Edwards syndrome, whereas the second genetic cell line showed normal 46,XX female. The present case was reported as dual gender chimera with chi 47,XY, + 18/46,XX karyotype pattern. To the best of available knowledge, dual gender chimerism with abnormal male trisomy 18 and normal female karyotype has not been reported so far, and this case is reported for its rarity and as the first report.

The Role of Cytogenetic Methods in the Diagnosis of Haematological Diseases

Introduction: Conventional cytogenetics by the use of standard karyotyping allows the study of numerical and structural chromosomal aberrations. Haematological malignancies include a number of cancer types that originate in the blood cells of the bone marrow or of the lymphatic system. Cytogenetic methods are traditionally used for the sake of diagnosis and prognosis of these diseases. However, with the ever more frequent use of molecular methods in the diagnostic laboratories, the importance of the conventional cytogenetic analysis in the diagnosis of haematological diseases needs to be reassessed. Aim: To evaluate the role of cytogenetic methods in the diagnosis of haematological malignancies. Materials and Methods: A retrospective analysis of cytogenetic findings of 146 patients with various haematological malignancies was performed. All of the findings were made over a period of three years at the Centre for Genetics at the Medical Faculty of the University of Sarajevo in Bosnia and Herzegovina. Microsoft Excel 2019 was used for the analysis and presentation of data in the form of tables and graphs. Results: The results of the present study showed that the use of conventional cytogenetic analysis is a good diagnostic method for 50.68% (74) of patients in whom chromosomal aberrations were detected. Conclusion: Cytogenetics remains the most comprehensive method for assessing chromosomal abnormalities due to its ability to detect clinically relevant aneuploidies and additional cytogenetic abnormalities that cannot be detected by locus-specific assays.