(BHD) is a very rare human genetic disorder
. The disorder has been reported in more than 100 families worldwide, and it is inherited
in an autosomal dominant
Birt-Hogg-Dubé syndrome is a rare disorder that affects the skin
and increases the risk of certain types of tumors
. The condition is characterized by multiple noncancerous tumors of the hair follicles
, particularly on the face, neck, and upper chest. These growths typically first appear in a person's twenties or thirties. People with Birt-Hogg-Dubé syndrome also have an increased risk of developing cancerous
or noncancerous kidney
tumors and possibly tumors in other organs and tissues. Additionally, affected individuals have a higher chance of developing cysts
in the lungs
and an abnormal collection of air in the chest cavity (pneumothorax
) that may result in the collapse of a lung.
Mutations in the FLCN
gene cause Birt-Hogg-Dubé syndrome. The FLCN
gene makes a protein called folliculin
. The normal function of this protein is unknown, but researchers believe that it may act as a tumor suppressor. Tumor suppressors normally prevent cells from growing and dividing too rapidly or in an uncontrolled way. Mutations in the FLCN
gene may interfere with the ability of folliculin to restrain cell growth and division, leading to the formation of noncancerous and cancerous tumors.
Researchers believe that two copies (instead of one copy) of the FLCN gene must be altered for a person to develop the kidney tumors often seen in Birt-Hogg-Dubé syndrome. People with this condition are born with one mutated copy of the FLCN gene in each cell. Then, during their lifetime, the other copy of the gene is mutated in kidney cells. These genetic changes result in no functional copies of the FLCN gene in these cells, allowing the cells to divide uncontrollably and form tumors.
The syndrome was first described in 1977
. The Myrovlytis Trust
has recently started supporting research into BHD syndrome. The Inaugural BHD syndrome Symposium was held in Roskilde, Denmark, in September 2008: 47 of the worlds leading BHD researchers and clinicians, as well as family members affected by BHD, attended this scientific meeting. More information about BHD syndrome is available at the world's first website dedicated to BHD syndrome - BHDSyndrome.org
This article incorporates public domain text from The U.S. National Library of Medicine