Osler-Weber-Rendu Syndrome and Hereditary Hemorrhagic Telangiectasia: They Are the Same Disease
Osler-Weber-Rendu syndrome and Hereditary Hemorrhagic Telangiectasia (HHT) are different names for the exact same autosomal dominant genetic disorder 1. There is no clinical, genetic, or pathophysiological difference between these terms.
Disease Overview
HHT (also called Osler-Weber-Rendu syndrome) is characterized by:
- Prevalence: Approximately 1 in 5000 people worldwide 1
- Inheritance: Autosomal dominant pattern 1
- Pathophysiology: Abnormal blood vessel formation resulting in telangiectasias and arteriovenous malformations (AVMs) 1, 2
Genetic Basis
The disease is caused by mutations in one of several genes:
- ENG gene (Endoglin) - HHT type 1 1
- ACVRL1/ALK1 gene (Activin receptor-like kinase-1) - HHT type 2 1
- SMAD4/MADH4 gene - Associated with a combined syndrome of HHT and juvenile polyposis 1, 3
Diagnostic Criteria
The diagnosis is based on the Curaçao criteria 1:
| Criteria | Description |
|---|---|
| Epistaxis | Spontaneous, recurrent nosebleeds |
| Telangiectases | Multiple at characteristic sites (lips, oral cavity, fingers, nose) |
| Visceral lesions | Pulmonary AVMs, liver AVMs, cerebral AVMs, spinal AVMs, GI telangiectases |
| Family history | A first-degree relative with HHT |
Diagnosis is:
- Definite: If three criteria are present
- Possible/suspected: If two criteria are present
- Unlikely: If fewer than two criteria are present
Clinical Manifestations
Common manifestations include:
- Epistaxis: Most common symptom, affecting >90% of adults with HHT 1
- Telangiectasias: Visible on skin and mucous membranes
- Gastrointestinal bleeding: From GI telangiectasias
- Anemia and iron deficiency: Due to chronic blood loss
- Arteriovenous malformations: Can occur in lungs, liver, brain, and spinal cord
- Complications: Stroke, brain abscess, high-output heart failure, portal hypertension, and liver failure 4, 5
Historical Context of the Name
The name "Osler-Weber-Rendu syndrome" comes from the physicians who described the condition:
- Henri Jules Louis Marie Rendu (French physician who first distinguished it from hemophilia)
- William Osler and Frederick Parkes Weber (who further characterized the disease) 1
The term "Hereditary Hemorrhagic Telangiectasia" is the more modern, descriptive name for the same condition, focusing on its key clinical features: hereditary nature, hemorrhagic tendency, and telangiectasias 1.
Management Approach
Management focuses on:
- Epistaxis: Nasal moisturization, antifibrinolytics, antiangiogenic therapies 1
- GI bleeding: Endoscopic therapies, antiangiogenic agents 1
- Anemia: Iron supplementation, blood transfusions 1, 6
- Screening: For visceral AVMs to prevent complications 1
- Liver involvement: Typically managed conservatively; liver transplantation for severe cases 1
Important Clinical Pearls
- Liver biopsy should be avoided in patients with suspected or confirmed HHT due to risk of hemorrhage 1
- Genetic testing is valuable for confirming diagnosis and family screening 1
- Bevacizumab has emerged as a promising therapy for reducing bleeding complications 1, 6
- The disease shows age-dependent penetrance with variable expressivity even within families with the same mutation 2
In clinical practice, both terms (Osler-Weber-Rendu syndrome and HHT) are used interchangeably in medical literature and clinical settings, with HHT being the more commonly used term in recent publications.