Down Syndrome
Some genetic disorders are the result of too many or too few chromosomes. In one such disorder, called Down syndrome, a person’s cells have an extra copy of chromosome 21, which means these people will have a total of 47 chromosomes instead of 46. Anyone can be born with down syndrome if there is a mutation during cell division. The extra chromosome is the result of an error during meiosis. Recall that in meiosis cells divide and chromosomes separate to produce sex cells with half of the normal number of chromosomes. Down syndrome most often occurs when chromosomes fail to separate properly during meiosis.
People with Down syndrome have a distinctive physical appearance, and have some degree of mental retardation which affects their brain and how they learn and develop skills. Heart defects are also common by can be treated. Despite their limitations, many people with Down syndrome lead full, active lives.
People with Down syndrome have a distinctive physical appearance, and have some degree of mental retardation which affects their brain and how they learn and develop skills. Heart defects are also common by can be treated. Despite their limitations, many people with Down syndrome lead full, active lives.