Bannayan-Riley-Ruvalcaba Syndrome

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This entry is adapted from the peer-reviewed paper https://medlineplus.gov/genetics/condition/bannayan-riley-ruvalcaba-syndrome

Bannayan-Riley-Ruvalcaba syndrome is a genetic condition characterized by a large head size (macrocephaly), multiple noncancerous tumors and tumor-like growths called hamartomas, and dark freckles on the penis in males. The signs and symptoms of Bannayan-Riley-Ruvalcaba syndrome are present from birth or become apparent in early childhood.

genetic conditions

1. Introduction

At least half of affected infants have macrocephaly, and many also have a high birth weight and a large body size (macrosomia). Growth usually slows during childhood, so affected adults are of normal height and body size. About half of all children with Bannayan-Riley-Ruvalcaba syndrome have intellectual disability or delayed development, particularly the development of speech and of motor skills such as sitting, crawling, and walking. These delays may improve with age.

About half of all people with Bannayan-Riley-Ruvalcaba syndrome develop hamartomas in their intestines, known as hamartomatous polyps. Other noncancerous growths often associated with Bannayan-Riley-Ruvalcaba syndrome include fatty tumors called lipomas and angiolipomas that develop under the skin. Some affected individuals also develop hemangiomas, which are red or purplish growths that consist of tangles of abnormal blood vessels. People with Bannayan-Riley-Ruvalcaba syndrome may also have an increased risk of developing certain cancers, although researchers are still working to determine the cancer risks associated with this condition.

Other signs and symptoms that have been reported in people with Bannayan-Riley-Ruvalcaba syndrome include weak muscle tone (hypotonia) and other muscle abnormalities, thyroid problems, and seizures. Skeletal abnormalities have also been described with this condition, including an unusually large range of joint movement (hyperextensibility), abnormal side-to-side curvature of the spine (scoliosis), and a sunken chest (pectus excavatum).

The features of Bannayan-Riley-Ruvalcaba syndrome overlap with those of another disorder called Cowden syndrome. People with Cowden syndrome develop hamartomas and other noncancerous growths; they also have an increased risk of developing certain types of cancer. Both conditions can be caused by mutations in the PTEN gene. Some people with Bannayan-Riley-Ruvalcaba syndrome have had relatives diagnosed with Cowden syndrome, and other individuals have had the characteristic features of both conditions. Based on these similarities, researchers have proposed that Bannayan-Riley-Ruvalcaba syndrome and Cowden syndrome represent a spectrum of overlapping features known as PTEN hamartoma tumor syndrome instead of two distinct conditions.

2. Frequency

The prevalence of Bannayan-Riley-Ruvalcaba syndrome is unknown, although it appears to be rare. Several dozen cases have been reported in the medical literature. Researchers suspect that the disorder is underdiagnosed because its signs and symptoms vary and some of them are subtle.

3. Causes

About 60 percent of all cases of Bannayan-Riley-Ruvalcaba syndrome result from mutations in the PTEN gene. Another 10 percent of cases are caused by a large deletion of genetic material that includes part or all of this gene. The protein produced from the PTEN gene is a tumor suppressor, which means that it normally prevents cells from growing and dividing (proliferating) too rapidly or in an uncontrolled way. If this protein is missing or defective, cell proliferation is not regulated effectively. Uncontrolled cell division can lead to the formation of hamartomas and other cancerous and noncancerous tumors. The protein produced from the PTEN gene likely has other important functions within cells; however, it is unclear how mutations in this gene can cause the other features of Bannayan-Riley-Ruvalcaba syndrome, such as macrocephaly, developmental delay, and muscle and skeletal abnormalities.

When Bannayan-Riley-Ruvalcaba syndrome is not caused by mutations or deletions of the PTEN gene, the cause of the condition is unknown.

4. Inheritance

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

5. Other Names for This Condition

Bannayan-Ruvalcaba-Riley syndrome
Bannayan-Zonana syndrome
BRRS
BZS
Myhre-Riley-Smith syndrome
Riley-Smith syndrome
Ruvalcaba-Myhre syndrome
Ruvalcaba-Myhre-Smith syndrome

References

Blumenthal GM, Dennis PA. PTEN hamartoma tumor syndromes. Eur J Hum Genet.2008 Nov;16(11):1289-300. doi: 10.1038/ejhg.2008.162.
Eng C. PTEN Hamartoma Tumor Syndrome. 2001 Nov 29 [updated 2016 Jun 2]. In:Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Stephens K, Amemiya A,editors. GeneReviews® [Internet]. Seattle (WA): University of Washington,Seattle; 1993-2020. Available from http://www.ncbi.nlm.nih.gov/books/NBK1488/
Eng C. PTEN: one gene, many syndromes. Hum Mutat. 2003 Sep;22(3):183-98.Review.
Hobert JA, Eng C. PTEN hamartoma tumor syndrome: an overview. Genet Med. 2009 Oct;11(10):687-94. doi: 10.1097/GIM.0b013e3181ac9aea. Review.
Lynch NE, Lynch SA, McMenamin J, Webb D. Bannayan-Riley-Ruvalcaba syndrome: a cause of extreme macrocephaly and neurodevelopmental delay. Arch Dis Child. 2009 Jul;94(7):553-4. doi: 10.1136/adc.2008.155663.
Marsh DJ, Coulon V, Lunetta KL, Rocca-Serra P, Dahia PL, Zheng Z, Liaw D,Caron S, Duboué B, Lin AY, Richardson AL, Bonnetblanc JM, Bressieux JM,Cabarrot-Moreau A, Chompret A, Demange L, Eeles RA, Yahanda AM, Fearon ER,Fricker JP, Gorlin RJ, Hodgson SV, Huson S, Lacombe D, Eng C, et al. Mutationspectrum and genotype-phenotype analyses in Cowden disease and Bannayan-Zonanasyndrome, two hamartoma syndromes with germline PTEN mutation. Hum Mol Genet.1998 Mar;7(3):507-15.
Marsh DJ, Kum JB, Lunetta KL, Bennett MJ, Gorlin RJ, Ahmed SF, Bodurtha J,Crowe C, Curtis MA, Dasouki M, Dunn T, Feit H, Geraghty MT, Graham JM Jr, HodgsonSV, Hunter A, Korf BR, Manchester D, Miesfeldt S, Murday VA, Nathanson KL, ParisiM, Pober B, Romano C, Eng C, et al. PTEN mutation spectrum and genotype-phenotypecorrelations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity withCowden syndrome. Hum Mol Genet. 1999 Aug;8(8):1461-72.
Parisi MA, Dinulos MB, Leppig KA, Sybert VP, Eng C, Hudgins L. The spectrumand evolution of phenotypic findings in PTEN mutation positive cases ofBannayan-Riley-Ruvalcaba syndrome. J Med Genet. 2001 Jan;38(1):52-8.
Zbuk KM, Eng C. Cancer phenomics: RET and PTEN as illustrative models. Nat RevCancer. 2007 Jan;7(1):35-45.
Zhou XP, Waite KA, Pilarski R, Hampel H, Fernandez MJ, Bos C, Dasouki M,Feldman GL, Greenberg LA, Ivanovich J, Matloff E, Patterson A, Pierpont ME, RussoD, Nassif NT, Eng C. Germline PTEN promoter mutations and deletions inCowden/Bannayan-Riley-Ruvalcaba syndrome result in aberrant PTEN protein anddysregulation of the phosphoinositol-3-kinase/Akt pathway. Am J Hum Genet. 2003Aug;73(2):404-11.

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Subjects: Genetics & Heredity

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Catherine Yang

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Entry Collection: MedlinePlus

Update Date: 24 Dec 2020

Table of Contents

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1. Introduction

2. Frequency

3. Causes

4. Inheritance

5. Other Names for This Condition

References

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1. Introduction

2. Frequency

3. Causes

3.1. The gene associated with Bannayan-Riley-Ruvalcaba syndrome

4. Inheritance

5. Other Names for This Condition

References