|
|
| Year:
2025 |
Month:
January
|
Volume:
14 |
Issue:
1 |
Page:
PO10 - PO13 |
A Cross-sectional Study on Molecular Cartography: The Mapping of Down Syndrome with Cytogenetic Tools
|
| |
Correspondence
A Deepa, K Chandramouleeswari, M Dougul Regis,
Dr. M Dougul Regis,
Assistant Professor, 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 :
|
 |
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.
|
| |
[ FULL
TEXT ] | [   ]
|
| |
Print
|
|