Microscopic examination of chromosomes to detect numerical and structural changes. The microscopic chromosome images are normally paired and arranged by size for examination and analysis.
Figure 1: Karyotype for a trisomy 21 patient (according to Dundar M, Uzak AS, Erdogan M, Akbarova Y. Prediction, prevention and personalisation of medication for the prenatal period: genetic prenatal tests for both rare and common diseases EPMA J. 2011 Jun; 2(2): 181–195.)