A married middle aged female gives history of repeated abortions for the past 5 years. Which of the following chromosomal anomaly is the most common cause for this?

• The given karyogram shows three chromosomes at 21 instead of a pair. It is called Trisomy 21. • Trisomy 21 is synonymous with Down’s syndrome and is the most common of the chromosomal disorders. It is a major cause of mental retardation. • Other trisomies are Edward syndrome (Trisomy 18) and Patau syndrome (Trisomy 13)