Introduction: Down syndrome is the most common genetic disorder throughout the world. There is a lot of literature contributed by various studies; however, very few studies have reported the frequency of various types of cytogenetic abnormalities and their association with various congenital defects in the individuals with Down’s syndrome.

Aim: To establish the clinical and cytogenetic correlation in the Down’s syndrome individuals.

Material and Methods: Retrospective analysis was done in 482 individuals with Down syndrome, who were clinically and cytogenetically evaluated during 2003 to 2015 in Genetic and Health Research Centre, Nashik, India.

Results: Out of 482 cases of Down syndrome studied, free trisomy 21 was identified in 422 cases (87.55%), translocation karyotype was observed in 36 cases (7.47%), mosaicism in 22 cases (4.56%) and two cases did not show any obvious chromosomal abnormality. 207 cases showed cardiac anomaly (42.95%), which were Atrio-Ventricular Canal Defect in 105 cases (51%), Ventricular Septal Defect in 62 cases (30%), Atrial Septal Defects and Patent Ductus Arteriosus in 17 cases each (8%) and Tetralogy of Fallot in 6 cases (3%). The frequencies of chromosomal abnormalities observed in Down’s syndrome cases with cardiac defects was 89.85% (186/207) for free trisomy 21, 8.17% (18/207) for translocation Down syndrome and 1.45% (3/207) for mosaicism. Non cardiac anomalies were observed in 92 patients (19%) and these were mostly in gastrointestinal tract, including duodenal atresia in 44 cases (9%), imperforate anus in 28 cases (6%) and Hirschsprung’s disease in 20 cases (4%). Mosaicism did not show any non-cardiac anomaly. 

Conclusion: Among Down syndrome with all types of chromosomal abnormalities, 42.95% cases had cardiac defects and 19.1% had non-cardiac defects. Cases with trisomy exhibit a common association with occurrence of ventricular septal defect while those with mosaicism, which was minimally found, had an association with Atrial Septal defect. Thus, careful clinical evaluation of both cardiac and noncardiac defects is warranted in all the new-borns with Down syndrome for early intervention and timely managemet.