Q: Every time you comment on someone’s concern about chronic nosebleeds, I worry so much about HHT, as this is the most common symptom. You write often on “orphan” diseases. Well, this one is large but certainly an orphan. There are hospital treatment centers of excellence to deal with this disease worldwide.

Both my husband and son suffer from almost daily nosebleeds. There are treatments available, though the condition can’t be cured.

A: HHT (hereditary hemorrhagic telangiectasis) a/k/a Osler-Weber-Rendu syndrome is an inherited autosomal dominant genetic disorder of blood vessels (arteries and veins) that affects approximately one in every 5,000 individuals – male and female alike from all ethnic groups. Our arteries carry blood under high pressure out to all areas of the body, while veins carry blood that should be under low pressure. Then there are usually very small blood vessels known as capillaries that connect arteries to veins. A person with HHT has a tendency to form blood vessels that lack normal capillaries, meaning that the blood under high pressure flows directly into a vein without first having to squeeze through very small capillaries. It’s where these arteries connect directly to veins that can rupture and bleed, simply because they are fragile. When the vascular formations present on the tongue, lips or skin, they may resemble pin-point red or brown dots. The abnormal blood vessel referred to in this instance is known as telangiectasis if it involves small blood vessels. These areas present on the lining of the nose and can be responsible for recurrent nosebleeds, the most common symptom of HHT. Other areas of the body affected include the liver, digestive tract, lungs, brain, and skin. When the abnormality involves a larger blood vessel, it is referred to as an arteriovenous malformation or AVM for short. Some individuals with HHT may also have AVMs in one or more organs. Those that occur in the lungs and brain may lead to serious complications. Therefore, the HHT Foundation strongly recommends that all patients and families with HHT be assessed for screening and treatment.

Each child born to an HHT parent has a 50% chance of inheriting the HHT gene mutation with one copy inherited from the father and the other from the mother. Individuals diagnosed with HHT have one normal copy of the gene and one mutated copy, so when a person with HHT has a child, he or she may either pass on the normal copy of the gene or the copy with the mutation. The child that inherits the gene with the mutation will have HHT, while the child who inherits the normal copy will not.

Diagnosis is accomplished through clinical examination or genetic testing, the latter consisting of analyzing DNA, the genetic material carried in cells. Genetic testing is commonly done on a small sample of blood but can also be accomplished on saliva. There are various types of genetic testing for HHT available. The first is known as “sequencing” of the genes that involves examining the precise sequence of building blocks in the DNA sample to determine if there is an abnormality. The next is “deletion and duplication” to determine if there is a piece of the gene missing or duplicated. Single mutation analysis reviews to determine if one particular mutation previously identified in another family member is either present or completely absent.

While there is no means to prevent telangiectasis or AVMs, most can be treated once they occur. The current recommendation for treatment will depend on the location of the body in which it occurs and its size. Because recurrent epistaxis (nose bleeds) occurs in up to 95% of all individuals with HHT, that particular event may lead to anemia which may be handled with iron supplements and other forms of treatment.

So, while this complex disease exists, I wouldn’t automatically make a rapid connection – although it certainly is a possibility – with HHT and nosebleeds. Yet thanks to your knowledge of the disorder, readers may now be better informed and can take steps to determine if this genetic disorder may be to blame. Additional extensive and easy-to-understand information can be found through the HHT Foundation by logging on to maryleigh.krock@hht.org or by calling 410 357-9932. There is also a newsletter published three times each year by the foundation that provides up-to-date information on this little known disorder. So, thank you for educating me to look beyond the obvious.