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Secugen - Genetic Diagnostic - HHT


Hereditary Hemorrhagic Telangiectasia (HHT)

Rendu-Osler–Weber Syndrome, also known as Hereditary Hemorrhagic Telangiectasia or HHT, is a vascular disorder whose prevalence is estimated at 1 in 3000-8000 individuals. Because of their diagnostic complications, these figures are usually underestimated.

HHT is characterized by the presence of multiple dilations in small caliber blood vessels (telangiectasia) prone to bleed, especially in nose (epistaxis) but also in urinary, digestive, respiratory and neurological organs.

The prognosis of patients can become very serious, depending on the visceral damage. HHT is an autosomal dominant genetic disease which has been associated with two genes:

  1. Endoglin gene (ENG): Mutations in this gene result in type 1 HHT. Currently more than 350 mutations have been described.
  2. Gene Activin receptor like-kinase type 1 (ALK-1): Mutations in this gene originate HHT type 2. There have been described 250 mutations.

Affected individuals have a mutated copy of the gene ENG or ALK-1. This makes the endothelial cells express only half functional protein, which is not sufficient for the cell to perform its function properly and as a result the disease is developed. This pathogenic mechanism is known as haploinsufficiency.


The diagnostic of HHT has traditionally been based on the presence of four clinical signs known as Curaçao criteria (1999). These criteria include: epistaxis, telangiectasias on skin and mucous membranes, occurrence of arteriovenous malformations in internal organs, and family history.

The diagnostic is definite if three or more criteria are met, however, due to the phenotypic variability of the disease, in many cases this does not occur, so the diagnostic is complicated.

Today, thanks to advances in genetic analysis based on the search for mutations in these genes, a conclusive new diagnostic tool is available to the clinicians.

Genetic analysis given by Secugen

In Secugen we offer a genetic analysis based on the complete sequencing and MLPA of ENG and ALK-1 genes with a short delivery time of about 4 weeks. This test is offered at an affordable price following strict quality controls.

In addition, we have the assistance of two spanish and internationally renowned experts in HHT: Dra. Luisa M. Botella Biological Research Center of CSIC and Dr. Roberto Zarrabeitia, Reponsible of the HHT Unit Hospital Sierrallana (Torrelavega, Santander).


Our genetic study is presented as a tool that opens up new alternatives:

  • Confirmation of diagnostic: Due to the high variability of the clinical picture of the disease, genetic analysis is presented as an essential confirmatory test.genético se presenta como una prueba confirmatoria imprescindible.
  • Early diagnostic: It is especially important in young patients, because diagnostic set before the appearance of clinical symptoms, can help to make appropriate decisions regarding treatment and prevent consequences of the disease that can become very serious.
  • Prevention: Allows to study patients with a family history of HHT and to anticipate the development of clinical manifestations.