Diagnosis of HHT


Any child born to an HHT patient has a 50-50 chance of inheriting the HHT gene. These children should be screened for brain and lung AVMs. For young children, these procedures require sedation/general anaesthesia, but they are vital in reaching proper diagnosis and care.

Genetic testing will be slightly easier if an HHT mutation has already been identified in a family member. Such testing will identify which family members have HHT and therefore need to be screened for internal AVMs.

Please consult your National HHT Centre in Mercy University Hospital Cork to make an appointment for screening. EMAIL

HHT can be diagnosed using the Curaçao criteria or by identifying a causative mutation


The Curaçao Criteria:

A Diagnosis is likely if 3 of the following clinical criteria are present.


  1. Spontaneous & Recurrent nosebleeds: Unexplained nosebleeds which may range from mild to severe. In many younger patients nosebleeds occur mainly whilst sleeping at night-time.
  1. Multiple telangiectases in typical locations (face, lips, oral cavity, fingers): Telangiectases are small red spots which disappear when pressed. They can appear on the skin of the hands, lips or face, or inside the nose or mouth.
  1. AVMs in other organs (lungs, liver, brain, gastro-intestinal tract, spinal cord): Screening of internal organs may be necessary to detect such AVMs.
  1. A 1st degree relative with HHT by these criteria: This would include parents, offspring and siblings.


Because many of the clinical manifestations of HHT may develop later in life, the Curaçao criteria is less sensitive for diagnosing HHT in children.

Asymptomatic children of a parent with HHT should be considered to have HHT, unless the disorder is excluded by genetic testing.

It is advised that a patient who suspects they might have HHT attends an HHT Specialist Centre for their diagnosis.