As many as 1 in 20 eggs produced after the age of 40 may carry this chromosome abnormality. Poor muscle tone, including heart muscle Tongue and mouth not proportioned, affecting speech Common mental retardation Immune system weak Trisomy of chromosome 13 and 18 also occur. Other Chromosome Abnormalities Polyploidy Increase in the number of sets of chromosomes, usually resulting from the formation of diploid gametes. Occurs naturally in many plants and may produce larger, hardier individuals. If both gametes are diploid, the individuals are often fertile.
Polyploidy is used extensively in developing agricultural varieties.
The impacts of these chromosomal alterations vary, depending on when and where. In some cases, the cell will not work, and dies. In gametes, they will be carried in all cell lines, and there is some evidence that some chromosomal alterations may activate oncogenes, or cancer causing genes. One form of leukemia is caused by a translocation.