Introduction

The Rendu-Osler-Weber disease or hereditary hemorrhagic telangiectasia (HHT) is a disease characterized by epistaxis, mucocutaneous telangiectases, and visceral arteriovenous malformations (AVMs) particularly in the brain, lung, gastrointestinal tract, and liver. Hereditary hemorrhagic telangiectasia is transmitted as an autosomal-dominant disorder whose phenotypic penetrance is age-dependent and nearly complete by age 40. Mutations in two different genes identify HHT type 1 and HHT type 2, respectively: endoglin (MIM#131195; XM_055188) located on chromosome 9q33-q34 and activin-like kinase type 1 (ALK-1) or ACVRL1 (MIM#601284; Z22533) on chromosome 12q13. The existence of a third locus has been predicted. Hereditary hemorrhagic telangiectasia type 1 is considered a more severe form of the disease with an earlier onset of epistaxis and telangectasia and an occurrence of pulmonary arteriovenous malformations higher than in HHT-2 subjects.

The heterogeneous clinical setting renders the diagnosis difficult, thus explaining why HHT was once considered a rare disease. Moreover, frequent misdiag-nosis has led to an underestimation of the actual prevalence of HHT which currently is 10-20/100,000. Extensive experience is necessary with both the various clinical expressions of the disease and the instrumental diagnostic possibilities for a correct diagnosis. In fact, a single biological test is not yet available and diagnosis is made following the clinical criteria: recurrent epistaxis, mucocutaneous telangiectases, autosomal-dominant inheritance, and visceral involvement. The diagnosis is considered definite if patients demonstrate at least three of the above criteria, suspected in the presence of two criteria, and excluded if only one criterion is present.

Recent progress in the field of genetics has permitted the identification of many gene mutations, thus, facilitating the characterization of the at-risk members of the same family.

How To Deal With Rosacea and Eczema

How To Deal With Rosacea and Eczema

Rosacea and Eczema are two skin conditions that are fairly commonly found throughout the world. Each of them is characterized by different features, and can be both discomfiting as well as result in undesirable appearance features. In a nutshell, theyre problems that many would want to deal with.

Get My Free Ebook


Post a comment