PTEN Hamartoma Tumor Syndrome is a genetic condition in which non-cancerous growths, called hamartomas, develop in different areas of the body. In addition to hamartomas, people can have other physical issues, including larger-than-average head size, abnormal skin growths, and intellectual disabilities.
People with PTEN Hamartoma Tumor Syndrome are at higher risk of developing breast, thyroid, kidney, uterus, colorectal, and skin cancer.
PTEN Hamartoma Tumor Syndrome is hereditary, which means it can be passed from parents to their children.
PTEN Hamartoma Tumor Syndrome is caused by changes in a gene known as PTEN. Genes carry information telling cells in the body how to work. The PTEN gene helps to control how and when cells grow, divide, and die.
Most people carry two working copies of the PTEN gene in their cells. One copy is inherited from each parent. Cells from people with PTEN Hamartoma Tumor Syndrome carry one working copy of PTEN and one copy that is changed. This change causes the gene to not work right. It is called a PTEN variant.
Between 10– 50% of children with PTEN Hamartoma Tumor Syndrome inherit the PTEN gene variant from a parent who also has the syndrome. The rest have a new PTEN variant that did not come from a parent. These children have no history of the syndrome in their family. In these cases, the change either happened in an egg or sperm cell when the child was formed or in one of the child’s cells during pregnancy. These children are the first in their families to have PTEN Hamartoma Tumor Syndrome.
No matter how they acquired their PTEN variant, people with PTEN Hamartoma Tumor Syndrome have a 50% (or 1 in 2) chance of passing it on to their children.
As people with PTEN Hamartoma Tumor Syndrome get older, the working copy of PTEN often becomes changed in some of their cells. When both copies of the gene are changed, cancer can develop. That is why people with PTEN Hamartoma Tumor Syndrome have a higher risk of developing cancer than people who do not.
A doctor may suspect this diagnosis based on physical exam and/or after looking at a person’s medical or family history. In most cases, a doctor or genetic counselor will ask questions about the person’s health and the health of other family members. Read more about genetic counseling and genetic testing.
Diagnosing this syndrome is usually done by sequencing the PTEN gene to find variants (gene changes).
People with PTEN Hamartoma Tumor Syndrome are at high risk for certain cancers. These cancers generally occur in adults, not children, with the condition. The average age of cancer diagnosis is about 30 to 50 years old. The exception is thyroid cancer, which sometimes occurs in children with PTEN Hamartoma Tumor Syndrome.
The lifetime risks for each type of cancer are:
- Breast: 85% (women)
- Thyroid (usually follicular, rarely papillary): 35%
- Renal cell (kidney): 35%
- Endometrium (uterus): 28%
- Colorectal: 9%
- Melanoma (skin): 5%
Rarely, people with PTEN Hamartoma Tumor Syndrome develop a type of brain tumor called cerebellar dysplastic gangliocytoma (also called adult-onset Lhermitte-Duclos disease). The exact risk of developing this type of tumor is unknown because it is so rare.
Cancer screening involves tests to check for cancer before symptoms occur. The goal is to find cancer at the earliest and most treatable stage. Guidelines for cancer screening are available online. Recommended screenings may change over time as doctors learn more about this syndrome, so these screening tests should be discussed with a health care provider who knows this syndrome well.
Other ideas to reduce the risk of cancer include:
- Eat a healthful diet with lots of fruits and vegetables
- Get regular exercise
- Avoid smoking or using tobacco products
- Avoid secondhand smoke
- Avoid excess sun exposure and always wear sunscreen, hat, and protective clothing when out in the sun
- Get medical attention for unusual or ongoing symptoms
People with PTEN Hamartoma Tumor Syndrome may have some of the following issues:
- Larger than average head (macrocephaly): 94%
- Skin abnormalities (trichilemmomas, acral or plantar keratosis, oral papilloma): 90%
- Non-cancerous growths in the digestive system (polyps): 90%
- Non-cancerous growths in the thyroid gland (nodules, goiter, or adenoma): 75%
- Non-cancerous growths in the breast (fibrocystic disease): 67%
- Intellectual/learning disability or autism spectrum disorder
Other issues may include non-cancerous growths in the uterus (fibroids), non-cancerous growths of fatty cells under the skin (lipomas), muscle weakness, an abnormally curved spine (scoliosis), and/or freckling of the penis.
Because of the medical concerns related to this syndrome, specialists in the following areas may need to assess a child with PTEN Hamartoma Tumor Syndrome:
- Developmental pediatrics
- Dermatology
- Gastroenterology
- Endocrinology
Resources about PTEN Hamartoma Tumor Syndrome:
- PTEN Hamartoma Tumor Syndrome Foundation (www.ptenfoundation.org)
- PTEN World (www.ptenworld.com)
- Genetics Home Reference: PTEN (ghr.nlm.nih.gov/gene/PTEN)
Other resources:
- Making Sense of Your Genes: A Guide to Genetic Counseling (www.ncbi.nlm.nih.gov/books/NBK115508/)
Adapted from educational materials developed by the St. Jude Children’s Research Hospital Cancer Predisposition Program