Bannayan-Riley-Ruvalcaba syndrome: Description, Causes and Risk Factors:
Bannayan-Riley-Ruvalcaba syndrome is a rare hereditary condition that most often can cause polyps (hamartomas) of the small and large intestine, an increased head size (macrocephaly), benign fatty tumors (lipomas), blood vessel changes (hemangiomas), and thyroid problems. Males with BRRS often have some freckling on the penis.
The features of BRRS usually start showing up in childhood. Babies are typically born with a larger head, longer body, and a weight over 9 pounds (4kg). After birth their growth slows and as a result, children and adults are of normal height and size. Sometimes children will also have decreased muscle tone (hypotonia) and/or learning difficulties and developmental delay. Benign fatty tumors under the skin or in the abdomen and intestinal polyps (most commonly hamartomatous polyps) are common. Hemangiomas, or raised red birthmarks caused by blood vessel changes, may also be present. Hemangiomas can be either on internal organs or on the skin.
Bannayan-Riley-Ruvalcaba is a genetic syndrome usually caused by a mutation in a gene known as PTEN. Mutations in this gene have been found in about 60 percent of all people with a clinical diagnosis of Bannayan-Ruvalcaba-Riley syndrome and about 40-80 percent of people with a clinical diagnosis of Cowden syndrome. The fact that both conditions are caused by mutations in the same gene explains why they share many similarities and why a physician must consider both possibilities when deciding upon a diagnosis and your health care management plan.
People diagnosed with BRRS do not necessarily have all the same features. Only 50 percent of children have developmental delays and learning problems, while the other 50 percent have normal development. About 45 to 80 percent of affected individuals will develop polyps on the intestine. People with BRRS who have a mutation in the PTEN gene (Phosphatase and tensin homolog) may also be at risk for the features associated with Cowden syndrome. Therefore, we have also included with those features as well.
Bannayan-Riley-Ruvalcaba syndrome can be inherited or passed from an affected parent to a child. BRRS has an autosomal dominant pattern of inheritance. This means that each child (male or female) with an affected parent has a 50 percent chance of inheriting the PTEN mutation and developing BRRS. Likewise each child has a 50 percent chance of not inheriting the mutation and not developing BRRS.
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Birth Weight greater than 4 kg/9 lbs.
- Low muscle tone (hypotonia).
- Motor delay, speech delay, and/ormild developmental delay.
- Myopathic process in proximal muscles.
- Hamartomatous polyps.
- Joint hyperextensibility.
- Pectus excavatum.
- Tan, nonelevated spots (freckling) on penis.
Genetic testing of the Bannayan-Riley-Ruvalcaba syndrome gene can identify if someone has a mutation causing BRRS. There is a charge for these services when provided by clinically approved laboratories. These charges may or may not be covered by insurance and should be discussed with your doctor or genetic counselor.
The usual test for Bannayan-Riley-Ruvalcaba syndrome is called gene sequencing. In sequencing, the individual components (“letters”) of the PTEN gene are examined in detail looking for a mutation. This test is very accurate, but only about 60% of people meeting the criteria for BRRS have an identifiable mutation. This means that 40 percent of people who meet the criteria for BRRS will not have an identifiable mutation and will have a normal test result even though they do have BRRS. This could be due to a limitation in the test, and some labs offer additional testing to detect rare mutations missed by sequencing. It may also be possible, although this has not been proven, that BRRS could be cause by a mutation in another gene that has not been identified yet.
Bannayan-Riley-Ruvalcaba syndrome testing may also be available to you through a research study. Unlike clinical testing, research-based testing may take many months or years, but it is usually done without any cost to you. It may also provide information and results that are not available on a clinical basis. You may want to consider these issues as you decide whether you wish to pursue either clinical or research-based testing. Your physician and genetic counselor can help you if you are interested in participating in a research study.
Bannayan-Riley-Ruvalcaba syndrome cannot be cured. Treatment is symptomatic aimed at improving quality of life. Physical and speech therapy can be beneficial. Clear information about BRRS will help teachers to support children at school. From early adult life, special care should be taken to monitor for the development of tumors.
At present it is not clear whether people who have a clinical diagnosis of BRRS but do not have a detectable PTEN mutation should follow these guidelines as well. You should discuss this further with your healthcare providers.
Both men and women should receive thyroid cancer screening that includes an ultrasound of the thyroid at age 18 and annual thyroid palpation (having a doctor feel the thyroid) after that. You might also consider having an annual ultrasound. Because thyroid nodules can be a common feature, an experienced endocrinologist should evaluate any thyroid nodules to determine if they require follow-up, such as a biopsy.
Skin cancer screenings should also be considered. Yearly visits to a dermatologist can help manage the CS skin findings and also screen for skin cancer.
Recent evidence suggests that the risk for colon cancer may be increased in people with BRRS. Currently it is recommended that people with BRRS have colonoscopy every 10 years beginning at age 50 like anyone in the general population.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.