Gorlin or Basal Cell Carcinoma syndrome and the PTCH1 and SUFU genes
Gorlin syndrome is caused by a germline mutation in the PTCH1 gene and less commonly, the SUFU gene. It is rare, affecting around 1 in 30,000 people. Gorlin syndrome is also known as Nevoid basal-cell carcinoma syndrome (NBCCS). Other terms that have been used include multiple basal-cell carcinoma syndrome and Gorlin–Goltz syndrome.
Individuals with Gorlin syndrome develop a type of skin cancer called basal cell carcinoma (BCCs). BCCs are common, particular on sun damaged, fair skin. However, in Gorlin syndrome BCC's may occur at a very young age and, in some people, hundreds or even thousands of BCCs may develop over a lifetime.
Most individuals with Gorlin syndrome develop multiple BCCs, most commonly on their face, arms and upper body. However, the signs and symptoms of Gorlin syndrome vary greatly from individual to individual, even in the same family.
Gorlin syndrome is diagnosed clinically, when an individual 2 of the major criteria: calcification of the falx cerebri, keratocystic odontogenic tumors, palmar / plantar pits or multiple BCCs.
- Almost all individuals over the age of 20 will have calcification of the falx cerebri, a membrane separating the hemispheres of the brain. This doesn't cause problems but shows up on a skull Xray.
- Cysts in the jaw (keratocystic odontogenic tumours) are also common and appear before age 30. They can cause swelling and tooth displacement. If these cysts are seen on a jaw Xray, the likelihood of finding a mutation in the PTCH gene is ~50%.
- Many individuals have punched out areas that appear on the palms of the hand or the soles of the feet, particularly after soaking in water. This is referred to as "pitting". They don't cause problems.
Other clinical findings in Gorlin syndrome include a unusual appearance of the the ribs and/or the spine, having a large head (macrocephaly) and wide-spaced eyes.
In less than 5% of children with Gorlin syndrome a rare brain tumour called a medulloblastoma (or primitive neuroectodermal tumor [PNET]) occurs. A non-cancer growth, called a fibroma, may occur in the heart in around 2% of individuals. Fibromas may also occur in the ovary in 20% of women with Gorlin syndrome (note: this doesn't affect fertility).
- Management involves a dental review with jaw Xray from age 8 and a once-off ultrasound of the heart to exclude a cardiac fibroma as a baby.
- Sun protection is very important. Skin examinations start at age 10 and when basal cell carcinomas occur, usual treats are used.
- Because mutations in the SUFU gene have a strong association with medulloblastoma in childhood, brain MRI screening is recommended every 4 to 6 months from 4 months of age to age 5
There is a 50% chance of a person who carries a germline PTCH or SUFU mutation, whether male or female, passing the mutation to their son or daughter. If a mutation is identified, then predictive testing is available for blood relatives.
Does this sound like you or your family?Has a PTCH1 or SUFU mutation been detected in a blood relative? Make an appointment with Dr Hilda High at Sydney Cancer Genetics. It is a confidential opportunity to discuss your personal and family history of cancer and genetic testing can be organised, if needed.
These links may be useful
- Support groups exist in Australia, the UK and the USA among others.
- The Cancer Genetics section of the Cancer Institute's eviQ website provides up-to-date Australian-based management guidelines
- If you want to participate in research into Gorlin syndrome, you can join the international registry. More information is available on the Gorlin Syndrome Alliance website