This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Chromosome 20p deletion is a chromosome abnormality that occurs when there is a missing (deleted) copy of genetic material on the short arm (p) of chromosome 20. The severity and the signs and symptoms depend on the size and location of the deletion and which genes are involved. Extremely small deletions (microdeletions) involving the distal end of chromosome 20p are relatively common and in some cases are passed from parent to child without causing any health problems (called a familial variant). In other cases, a 20p deletion causes signs and symptoms such as developmental delay, growth delay, learning difficulties, distinctive facial features, birth defects, and/or various medical problems.
Some 20p deletions are not inherited and occur randomly during the formation of egg or sperm cells, or very early in fetal development. Other 20p deletions are present because a parent has a rearrangement of genetic material on his/her chromosomes. This rearrangement is usually a balanced translocation, which typically does not cause any health problems. Occasionally, a parent has the same deletion as his/her child. Chromosome testing of both parents can provide information about whether the deletion was inherited. If a parent has the same deletion as the child and does not have signs or symptoms, a genetics doctor usually assumes that the 20p deletion is not the cause of the child’s signs and symptoms. Treatment for chromosome 20p deletion is based on the signs and symptoms in each person.
This page is meant to provide general information about 20p deletions. You can contact GARD if you have questions about a specific deletion on chromosome 20p. To learn more about chromosome abnormalities, please visit our GARD webpage on FAQs about Chromosome Disorders.
For more information, visit GARD.