How often can Down syndrome occur?

By Qendra Jonathan

It is believed that individuals with Down syndrome have always existed. It wasn’t until 1866, however, when English doctor John Langdon Down published the description of the condition, which later took his name. In 1959 Professor Jerome Lejeune proved that Down syndrome is a chromosomal disorder. Instead of the 46 chromosomes that should normally be present in each cell, dr. Lejun noticed that individuals with Down syndrome had 47 chromosomes. Later, it was determined that this extra chromosome resulted in some physical characteristics and a different state during the developmental process.

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