OBJECTIVES: I. Examine screening modalities for pulmonary vascular arteriovenous malformation (PAVM) in individuals with endoglin mutations.

II. Examine the prevalence of cerebral arteriovenous malformations (CAVM) in individuals with hereditary hemorrhagic telangiectasia (HHT).

III. Investigate whether modifier genes exist that determine which individuals with HHT due to an endoglin mutation develop PAVMs and which develop CAVMs.

IV. Investigate the frequency of cardiac valve abnormalities in individuals affected with HHT due to an endoglin mutations.

PROTOCOL OUTLINE: Patients with hereditary hemorrhagic telangiectasia (HHT) undergo 5 different screening methods to determine which method is most effective in detecting arteriovenous malformations (AVM). Patients may participate in more than one screening method.

In part 1, patients undergo 3 different screening techniques (e.g., pulse oximetry, spiral computed tomography (CT), and contrast echocardiography) to detect pulmonary arteriovenous malformations (PAVM).

Patients in part 2 undergo magnetic resonance imaging (MRI) using gadolinium as the contrasting agent for AVM in the brain, known as cerebral arteriovenous malformations (CAVM). For pregnant women, this procedure may only take place if there is clinical evidence that suggests CAVM.

In part 3, Doppler ultrasound is used to screen for hepatic arteriovenous malformations (HAVM). The abdomen of each patient is viewed to detect AVM in the liver.

Patients in part 4 undergo echocardiograms as the screening method used to determine common heart valve abnormalities.

In part 5, blood samples are drawn from patients and analyzed to locate modifier genes as a possibility in determining severity of HHT.

• Osler-Rendu-Weber disease (or hereditary hemorrhagic telangiectasia)