Osler-Weber-Rendu syndrome is an inherited disorder of the blood vessels that can cause excessive bleeding.

Osler-Weber-Rendu syndrome is an inherited condition. It can affect males or females of any ethnic or racial group.

People with this condition can develop abnormal blood vessels called arteriovenous malformations (AVMs) in several areas of the body. If they are on the skin, they are called telangiectasias. The AVMs can also develop in other areas of the body, such as the brain, lungs, liver, or intestines.

The syndrome is genetic, which means it results from an abnormality in one of a few genes. Scientists have identified some of the genes involved. However, they do not know exactly how the gene defects lead to the abnormal blood vessels seen in persons with this syndrome.