Numerical Disorders
This is called aneuploidy (an abnormal number of chromosomes), and occurs when an individual is missing either a chromosome from a pair (monosomy) or has more than two chromosomes of a pair (trisomy, tetrasomy, etc.).
In humans an example of a condition caused by a numerical anomaly is Down Syndrome, also known as Trisomy 21 (an individual with Down Syndrome has three copies of chromosome 21, rather than two). Trisomy has been determined to be a function of maternal age.
An example of monosomy is Turner Syndrome, where the individual is born with only one sex chromosome, an X.
Read more about this topic: Chromosome Abnormality
Famous quotes containing the words numerical and/or disorders:
“There is a genius of a nation, which is not to be found in the numerical citizens, but which characterizes the society.”
—Ralph Waldo Emerson (1803–1882)
“It no longer makes sense to speak of “feeding problems” or “sleep problems” or “negative behavior” is if they were distinct categories, but to speak of “problems of development” and to search for the meaning of feeding and sleep disturbances or behavior disorders in the developmental phase which has produced them.”
—Selma H. Fraiberg (20th century)