Nevoid Basal Cell Carcinoma Syndrome is caused by changes in one of three genes known as PTCH1, PTCH2, or SUFU. Genes carry information telling cells in the body how to work. The PTCH1, PTCH2, and SUFU genes help to control how cells grow and divide.
Most people without Nevoid Basal Cell Carcinoma Syndrome carry two working copies of the PTCH1, PTCH2, and SUFU genes in their cells. One copy of each of these genes is inherited from each parent. Cells from people with Nevoid Basal Cell Carcinoma Syndrome carry one copy of PTCH1, PTCH2, or SUFU that is changed. This change causes the gene to not work right. It is called a variant.
Most children with Nevoid Basal Cell Carcinoma Syndrome inherit their variant from a parent who also has the syndrome. About 20–30% of children have a new 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 Nevoid Basal Cell Carcinoma Syndrome. No matter how they acquired the PTCH1, PTCH2, or SUFU variant, people with Nevoid Basal Cell Carcinoma Syndrome have a 50% (or 1 in 2) chance of passing it on to their children.
Most people born with one PTCH1, PTCH2, or SUFU variant will have some signs and symptoms of the condition in childhood. These can include a large head, distinct facial features, or defects in the ribs and spine. During a person’s life, the second copy of the PTCH1, PTCH2, or SUFU gene might also become changed in one or more cells of the body, such as the skin or brain. When this happens, those cells can develop into a tumor. This is why people with Nevoid Basal Cell Carcinoma Syndrome have a greater risk of developing tumors, such as basal cell carcinomas or medulloblastoma.
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 PTCH1, PTCH2, and SUFU genes to find variants (gene changes).
People with Nevoid Basal Cell Carcinoma Syndrome are at higher risk for the following cancerous tumors:
- Medulloblastoma, a brain tumor that occurs in children
- Basal cell carcinoma, the most common form of skin cancer
People with Nevoid Basal Cell Carcinoma Syndrome are at higher risk for the following non-cancerous tumors:
- Painless cysts in the jaw, called jaw keratocysts
- Tumors in the connective tissue of the ovaries and heart, called fibromas
Although people with Nevoid Basal Cell Carcinoma Syndrome are at higher risk for tumors, some people never develop them. Others might develop many tumors. About 5% of children with Nevoid Basal Cell Carcinoma Syndrome develop medulloblastoma. This happens most often around 2 years of age. Basal cell carcinomas appear in about 90% of people with the syndrome, usually starting in the teenage years. Jaw cysts occur in about 90% of people with this condition. Most appear in the teenage years, but some can occur in younger children. Fibromas of the heart occur in about 2% of people with Nevoid Basal Cell Carcinoma Syndrome and are often present at birth. Fibromas of the ovary occur in about 20% of females with the condition.
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 Nevoid Basal Cell Carcinoma Syndrome may also have some or all of the following:
- Small pits in the palms of the hands or soles of the feet
- Large head size (macrocephaly), sometimes caused by too much fluid in the brain (hydrocephalus)
- Distinct facial features, such as wide-set eyes, a jaw that juts out and a prominent forehead
- Tiny white cysts (bumps), called milia, around the cheeks, eyes, and lips
- Defects in the ribs and spine
- Extra fingers and toes
- Eye conditions, such as cataracts, “lazy” eye, a very small eyeball or missing structures in the eye
- Cleft lip
- Cleft palate
Most people with Nevoid Basal Cell Carcinoma Syndrome have only some of these features. It is important for people with Nevoid Basal Cell Carcinoma Syndrome to be evaluated by their pediatrician or family physician for these non-tumor issues and to be referred for imaging (MRI, X-rays, or ultrasounds) or evaluation by other specialists as needed.
People with Nevoid Basal Cell Carcinoma Syndrome need to avoid exposure to radiation. When X-rays are needed, people with this condition should find a center that can do digital X-rays.
Because of the medical concerns related to this syndrome, specialists in the following areas may need to assess a child with Nevoid Basal Cell Carcinoma Syndrome:
- Dermatology
- Cardiology
- Ophthalmology
- Orthopedics
- Otolaryngology (Ear, nose, and throat specialist)
- Gynecology
Resources about Nevoid Basal Cell Carcinoma Syndrome:
- Basal Cell Carcinoma Nevus Syndrome Life Support Network (www.gorlinsyndrome.org)
- Genetics Home Reference: Gorlin syndrome (ghr.nlm.nih.gov/condition/gorlin-syndrome)
- Skin Cancer Foundation (www.skincancer.org/)
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