#Mosaic down syndrome celebrities full#
While all forms of Down syndrome are associated with an extra full or partial 21st chromosome, there are a few different types of the condition. Also, because every gene in the extra 21st chromosome is affected, children with Down syndrome “may have medical conditions that affect every part of the body,” Pipan adds. The extra genetic material is present from the moment of conception, so Down syndrome is not something a person can develop after birth or later in life: You’re either born with it or you’re not. “But the 21st chromosome has 350 genes, and probably all of them contribute to Down syndrome,” Pipan says. ( Cystic fibrosis and muscular dystrophy are two examples of these single-gene disorders.) ( 3) And Pipan points out that many disorders stem from a single gene abnormality or mutation. Pipan explains.Įvery chromosome carries dozens, hundreds, or even thousands of specific genes.
When someone has Down syndrome, they have all 23 pairs of their chromosomes, but they are also born with an extra full or partial copy of the 21st chromosome, Dr. ( 2) Those 46 chromosomes are a person’s genetic blueprint - the stuff that makes them who they are, determining things like eye color, personality traits, and inherited risk of different diseases. By definition, Down syndrome is a genetic condition whereby an individual has a surplus of DNA material, says Mary Pipan, MD, a behavioral pediatrician and director of the Trisomy 21 Program at Children's Hospital of Philadelphia.Ī super quick genetic chemistry lesson is probably in order here.Įvery cell in a person’s body contains their genetic code, or DNA, which typically consists of 23 pairs of chromosomes - with one chromosome in each pair coming from the child’s mother and the other chromosome in each pair coming from the child’s father.
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