What is BHD?

Birt-Hogg-Dubé (BHD) syndrome is a hereditary condition that was identified in 1977 by three Canadian doctors – Arthur R. Birt, Georgina R. Hogg, and William J. Dubé. BHD syndrome was initially identified as a skin condition after skin lesions were found on the faces and necks of several members of an extended family. In recent years, more symptoms have been linked to this syndrome. People with BHD syndrome may have lung cysts or experience collapsed lungs, and may develop kidney cancer.

There is no typical BHD patient. Different family members with the syndrome may have none, one, or all of the symptoms of BHD. There is no way of knowing who will get which symptoms. The most serious symptom of BHD syndrome is kidney cancer; however, the risk for kidney cancer is estimated to be between 16-30%.

BHD syndrome is caused by mutations in the Folliculin gene (FLCN). A diagnostic genetic test looks for mutations in this gene and can determine if an individual has the syndrome. The syndrome affects both males and females equally, and because the disorder is dominant rather than recessive, every son or daughter of an individual who has BHD syndrome has a 50% chance of inheriting it. The best way of knowing whether you have BHD syndrome is to look for mutation in your Folliculin gene.

If you have BHD syndrome, then one of your parents almost certainly has the mutation. Your aunts, uncles and cousins may also have the syndrome. In an extraordinarily rare case, you could be the first in your family who has a mutation of the FLCN gene: this arises as a result of a spontaneous (de novo) mutation.

BHD is currently considered to be a rare syndrome. In May 2012, Orphanet estimated that 1 in 200,000 people have BHD syndrome. Because of the wide range of symptoms and because doctors encounter so few BHD patients, we expect that the syndrome is under-diagnosed. Most patients are only identified when they are diagnosed with fibrofolliculomas or kidney cancer.

Researchers are currently investigating the function of the Folliculin protein and how a mutation in this gene leads to the symptoms seen in Birt-Hogg-Dubé syndrome. The aim of current scientific research is to develop drugs and treatments to relieve the symptoms of, and ultimately cure, BHD syndrome.


The ‘What is BHD?‘ document provides a more detailed clinical description of the syndrome and the state of current scientific research. Although it is primarily aimed at scientists, it is freely available to download.

There are also other conditions which, like BHD syndrome, are hereditary kidney cancer syndromes and share similarities with BHD. A description can be found here.


For more information on genetic inheritance and autosomal dominant inheritance, see the Genetics Home Reference handbook: Inheritance patterns (NIH)



Publication date: September 2012
Review date: September 2015