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Preimplantation Genetic Testing for Structural Rearrangements
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Inmaculada Campos-Galindo, Vanessa Peinado
Infertility is a multifactorial condition of increasing prevalence [1,2]. Chromosome abnormalities appear to play important roles in its etiology [3]—these aberrations are 2–3 times more common in infertile individuals than in the general population [4,5] and are responsible for gestational pregnancy losses, implantation failures, and congenital malformations. Indeed, the prevalence of infertility in individuals with chromosome abnormalities is up to 25 times higher than in the general population [6–8]. Consequently, chromosome analysis is an essential part of the infertility evaluation (both members of the couple) to maximize the probability of pregnancy and minimize the transmission of chromosomal/genetic anomalies to the offspring.
Basic genetics and patterns of inheritance
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Performing cytogenetic analysis has become an integral part of many areas of medical practice, including obstetrics, pediatrics, and oncology. Traditional chromosome analysis first involves obtaining a sample of living tissue. This can be blood, skin, amniotic fluid, products of conception, bone marrow, or any viable solid tissue. Blood is the most frequently analyzed tissue for routine chromosome analysis. For blood, the lymphocytes are isolated. For amniotic fluid, the amniocytes are obtained by spinning down the fluid and removing the cell pellet. For solid tissues, the tissue is minced and/or sonicated. For all tissue types, the cells are cultured in tissue culture for 48 to 72 hours. Cell division is arrested at metaphase by the addition of colcemid. The cells are then harvested and placed on a microscope slide. The cell nuclei are ruptured by adding a hypotonic solution, then stained to show the bands, and images of the metaphase chromosome spreads are analyzed. Each chromosome is studied by looking at the banding pattern to identify not only numerical abnormalities, but also structural problems. Newer computerized technology allows karyotype analysis by digital imaging methods. By convention, the 22 autosome pairs are arranged by size, from the largest to the smallest, in four rows, with the pair of sex chromosomes in the lower right corner (Fig. 1). Ideograms are schematic representations of banding patterns used by cytogeneticists to standardize numbering of specific bands (Fig. 2).
Genetics and metabolic disorders
Published in Jagdish M. Gupta, John Beveridge, MCQs in Paediatrics, 2020
Jagdish M. Gupta, John Beveridge
3.37. Which of the following techniques is/are used for DNA testing?Polymerase chain reaction.Chromosome analysis.Genetic probes.Southern blotting.In situ hybridization.
Very severe immune aplastic anemia after mRNA vaccination against COVID-19 responds well to immunosuppressive therapy: clinical characteristics and comparison to previous reports
Published in Hematology, 2022
Suhyeon Woo, Bohyun Kim, Sang-Cheol Lee, Min-Sun Kim, Young Ahn Yoon, Young-Jin Choi
In our patient, the chromosomal abnormality t(11;14)(p10;p10) was found. Generally, the t(11;14)(q13;q32) abnormality can be found in plasma cell myeloma and other hematologic malignancies, but there was no evidence of other hematologic malignancies, including myeloma, in the patient’s bone marrow study. The t(11;14)(p10;p10) abnormality has not been reported to be associated with any specific hematologic malignancies. No specific genes have been identified in this location but clonal mosaicism of the chromosome has been found in many normal tissues. Some benign clonal populations are common in AA [8]. Therefore, the significance of this chromosomal abnormality was inconclusive. Close bone marrow study follow-ups and chromosomal analysis should be done to evaluate the clinical significance of a chromosomal abnormality. Next-generation sequencing (NGS) can detect mutations associated with myeloid malignancies in nearly 20% of the patients with AA [20]. Unfortunately, we could not perform an NGS study. However, a genetic abnormality is not an essential requirement for the diagnosis of AA. Therefore, we could diagnose AA in our patient.
A rare case of spontaneous tumor lysis syndrome in multiple myeloma
Published in Journal of Community Hospital Internal Medicine Perspectives, 2020
Louay Aldabain, Lyn Camire, David S. Weisman
A 58-year-old male presented with worsening lethargy, dyspnea, orthopnea, and paroxysmal nocturnal dyspnea of 1-week duration and decreased urine output for the last 2–3 days prior to his presentation. His past medical history was significant for morbid obesity, gout, sarcoidosis, chronic right-sided heart failure, COPD on 3 L home oxygen, atrial fibrillation, chronic kidney disease, pulmonary hypertension, and obstructive sleep apnea. The patient presented to another hospital with acute or chronic hypoxic respiratory failure, acute renal failure, and hyperkalemia and was discharged 8 days prior to presentation at our hospital. Initial workup revealed Bence-Jones proteinuria lambda U at 7500 mg/dL, and a bone survey revealed a skull lesion. Bone marrow biopsy demonstrated diffuse marrow replacement by plasma cells accounting for nearly 85% of nucleated cells, consistent with multiple myeloma (Figures 1–4). Chromosomal analysis was normal. The patient was discharged with a plan to initiate treatment for multiple myeloma after discharge.
New mutation causing androgen insensitivity syndrome – a case report and review of literature
Published in Gynecological Endocrinology, 2019
Marzena Maciejewska-Jeske, Patrycja Rojewska-Madziala, Karolina Broda, Karolina Drabek, Anna Szeliga, Adam Czyzyk, Stanislaw Malinger, Anna Kostrzak, Agnieszka Podfigurna, Gregory Bala, Blazej Meczekalski, Agnieszka Malcher, Maciej Kurpisz
The androgen receptor (AR) gene is located proximally on the long arm of chromosome X (locus Xq11-12) [15]. It encodes a transcription factor containing three major functional domains: the ligand-binding domain, the DNA-binding domain, and the N-terminal domain [16]. Over 1000 mutations causing AIS have been identified in the AR gene. Most of these are missense mutations, with numerous splicing mutations as well. Insertion and deletion mutations are relatively rare at this site [16]. In our case, chromosome analysis using GTG method was carried out. It revealed 46, XY karyotype with a single-base exchange in AR gene, which was the substitution from cytosine to thymine in chromosome X:66942710 position (referred to human reference genome GRCh37) which has resulted in an amino acid changes from leucine (CTT) to phenyloalanine (TTT) in ligand-binding domain. Recently, several new mutations in the AR gene have been reported and linked to AIS. Wu et al. reported four new mutations (insertions and deletions) in exons 1, 6, and 8 (c.1368_1369insGGCGGC, c.1436delC, c.2440_2441delTT, c.2633_2634insAGTTCAC) [17]. Similarly, Wang et al. discovered a new splice acceptor site mutation (c(0).1769-1G > C) [18].