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Mosaic ACVRL1 and ENG mutations in hereditary haemorrhagic telangiectasia patients
  1. D Hunter Best1,2,
  2. Cecily Vaughn2,
  3. Jamie McDonald1,3,
  4. Kristy Damjanovich2,
  5. James R Runo3,4,
  6. Jason M Chibuk5,
  7. Pinar Bayrak-Toydemir1,2
  1. 1Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, USA
  2. 2ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, Utah, USA
  3. 3HHT Center, Department of Radiology, University of Utah, Salt Lake City, Utah, USA
  4. 4Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
  5. 5Department of Medicine, Division of Medical Genetics, University of California San Diego, La Jolla, California, USA
  1. Correspondence to Dr Pinar Bayrak-Toydemir, Medical Directorship, ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108-1221, USA; pinar.bayrak-toydemir{at}


Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder caused by mutations in the ACVRL1, ENG, and SMAD4 genes. HHT is commonly characterised by small arteriovenous malformations (AVMs) known as telangiectasias of the skin, oral or gastrointestinal mucosa, as well as larger AVMs of solid organs (lungs, liver, brain). However, the manifestations of HHT are extremely variable. Two patients with no family history of HHT and strikingly different clinical presentations, who are mosaic for mutations in the ACVRL1 or ENG gene, are reported here. These cases represent the first report of mosaicism in patients clinically affected with classical HHT and pulmonary arterial hypertension, and suggest the need for awareness of mosaicism when performing clinical testing for this disorder.

  • HHT
  • mosaicism
  • pulmonary arterial hypertension
  • PAH
  • ENG
  • ACVRL1
  • cardiovascular medicine
  • diagnostics tests
  • molecular genetics

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  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval ARUP Laboratories has obtained approval from the University of Utah Institutional Review Board (IRB) to perform research studies and publish findings of these studies on patients who willingly sign the “Consent and Authorization for Publication of Personal Health Information” form. This approval was approved on 9/22/10. Signed consent forms have been submitted with our manuscript.

  • Provenance and peer review Not commissioned; externally peer reviewed.