Original article / research
Year :
2025 |
Month :
January
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Volume :
14 |
Issue :
1 |
Page :
PO10 - PO13 |
Full Version
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A Cross-sectional Study on Molecular Cartography: The Mapping of Down Syndrome with Cytogenetic Tools
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A Deepa, K Chandramouleeswari, M Dougul Regis 1. Postgraduate, Institute of Pathology, Madras Medical College, Chennai, Tamil Nadu, India.
2. Professor and Head, Institute of Child Health and Hospital for Children, Madras Medical College, Chennai, Tamil Nadu, India.
3. Assistant Professor, Institute of Child Health and Hospital for Children, Madras Medical College, Chennai, Tamil Nadu, India.
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Correspondence
Address :
A Deepa, K Chandramouleeswari, M Dougul Regis, Dr. M Dougul Regis,
Department of Pathology, A Block, No.15, Institute of Child Health and Hospital for Children, Halls Road, Tamilsalai, Egmore, Chennai-600008, Tamil Nadu, India.
E-mail: dougulregis@gmail.com
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| ABSTRACT |  | : Introduction: Down Syndrome (DS), or trisomy 21, is the most common genetic cause of intellectual disability among children, with an incidence of 1 in 700 births. This extra copy of chromosome 21 leads to characteristic clinical features known as Down facies, which include microcephaly, hypertelorism, a flat nasal bridge, macroglossia, a fissured tongue, microophthalmia, large ears, and various physical abnormalities like short stature, a short neck, a sandal gap, and a single palmar crease. Additionally, individuals with DS often experience intellectual disabilities, including delayed speech development and slow learning. Although the characteristic phenotypes are available for diagnosing DS, genetic testing is necessary for confirmation.
Aim: To confirm the diagnosis of DS through karyotyping, a cytogenetic analysis.
Materials and Methods: This cross-sectional study was conducted in the Department of Pathology (Molecular Pathology Laboratory) at the Institute of Child Health, Madras Medical College, Chennai, Tamil Nadu, India over a period of eight months from September 2023 to April 2024. The study included 50 patients, all children aged between 10 days and six years, who exhibited clinical features of DS. A peripheral blood sample of 3 mL was collected in a heparinised vacutainer. Karyotyping was performed, and the samples were stained with Giemsa banding using trypsin digestion. Metaphase spreads were examined under a microscope (Olympus) with the assistance of Applied Spectral Imaging (ASI) software, and karyotype descriptions were made according to the International Standard Committee on Human Cytogenetics Nomenclature guidelines. Descriptive analyses were conducted using Statistical Package for Social Sciences (SPSS) software version 29.0.2. Parameters like age, gender, risk factors (including elderly mothers and children born to consanguineous parents), and common associations (such as cardiovascular abnormalities) were analysed.
Results: Among the 50 children with clinical features of DS, a genotypic correlation was found in 48 children (96%). Among these, pure trisomy 21 was identified in 34 children (70%), Robertsonian translocation in 9 (20%) children, and mosaics in 5 (10%) children. The cardiovascular system was the most commonly affected system, with 38 (80%) children showing abnormalities, and 28 (60%) children were born to elderly primiparous mothers, making this the most frequently observed risk factor.
Conclusion: Despite advancements in non invasive prenatal screening techniques, karyotyping remains a definitive and widely used method for diagnosing DS. Continued research in this field aims to improve early detection and expand the understanding of the genetic mechanisms underlying the disorder. |
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Keywords
: Karyotyping, Trisomy 21, Translocation |
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DOI and Others
: DOI: 10.7860/NJLM/2025/74501.2896
Date of Submission: Jul 25, 2024
Date of Peer Review: Aug 14, 2024
Date of Acceptance: Oct 22, 2024
Date of Publishing: Jan 01, 2025
AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. NA
PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Jul 26, 2024
• Manual Googling: Sep 24, 2024
• iThenticate Software: Oct 21, 2024 (9%)
ETYMOLOGY: Author Origin
EMENDATIONS: 8
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