People with trisomy 21 develop Down’s syndrome. What law of Mendelian inheritance is violated in this disease? What is the most likely way this occurs?

Down's syndrome is a condition produced by excess gene located on chromosome 21 because of inappropriate cell division. Trisomy 21 induces Down syndrome in 95 percent of cases, which shows the individual does have three copies of chromosome 21 rather than the standard two copies among all cells. It is a genetic problem. It contains genetic abnormalities, learning difficulties, and facial characteristics defects. A disabled child might have heart conditions as well as sight and hearing troubles.

A trisomy condition occurs when a patient receives three copies of the chromosome and not the typical pairing. These are a violation to the Segregation law of genetics and happens whenever the chromosomes lack to split throughout the first cycle of meiosis.