Sometimes, a person is born with one or more
extra chromosomes in each cell. This usually
results in abnormalities because the affected
person has
(1) a reduced number of genes in cell nuclei
(2) fewer cell mutations than a person with a
normal chromosome number
(3) more genes in each cell than a person with a
normal chromosome number
(4) less DNA in cell nuclei, but more proteins in
cell mitochondria
