Prevalence of Hereditary Hemorrhagic Telangiectasia
The prevalence of hereditary hemorrhagic telangiectasia (HHT) is approximately 1 in 5,000 persons worldwide, making it the second most common inherited bleeding disorder after von Willebrand disease. 1, 2, 3
Global Prevalence Estimates
The most widely accepted prevalence estimate is 1 in 5,000 individuals globally, based on multiple guideline sources and recent clinical data 1, 2, 3
Some epidemiological studies suggest a range between 1.5 to 2 per 10,000 persons (equivalent to 1 in 5,000-6,667), though the lower estimate of 1 in 5,000 appears most consistent across high-quality sources 4
An even more conservative estimate of 1 in 10,000 has been reported in older literature, but this likely represents underdiagnosis rather than true prevalence 5
Regional Variation and Underdiagnosis
A 2024 population-based study from Buenos Aires, Argentina identified a prevalence of 3.2 per 10,000 (1 in 3,125) in a prepaid health maintenance organization, which is notably higher than global estimates 6
This higher prevalence in the Argentine study likely reflects better case detection in an organized healthcare system rather than true geographic variation, highlighting that HHT remains significantly underdiagnosed in most populations 6
The female-to-male ratio in the Argentine cohort was approximately 2:1 (3.9 per 10,000 in women versus 2.1 per 10,000 in men), though this may reflect ascertainment bias rather than true sex differences in disease occurrence 6
Clinical Significance of Prevalence
With a prevalence of 1 in 5,000, HHT affects an estimated 1.4 million people worldwide, making it far more common than many other rare diseases and warranting systematic screening approaches 3, 7
The autosomal dominant inheritance pattern means each child of an affected parent has a 50% chance of inheriting the condition, allowing transmission through multiple generations 1, 8
Despite affecting up to 1 in 5,000 individuals, HHT remains a rare and underdiagnosed condition, with many patients experiencing significant diagnostic delays that can lead to preventable complications 6, 7
Important Caveats
The true prevalence may be higher than reported estimates due to variable penetrance and age-dependent expression of clinical features, with epistaxis typically beginning around age 11 years and telangiectasias developing later in life 1
Population-based epidemiological studies are crucial for accurately quantifying disease burden, but remain limited in most geographic regions 6