Birt-Hogg-Dube syndrome
Meaning of Birt-Hogg-Dube syndrome: An inherited trio of skin bumps, lung cysts and kidney tumors, most often noticed when a lung suddenly collapses.
Definition of Birt-Hogg-Dube syndrome
Birt-Hogg-Dube syndrome is an inherited disorder caused by a fault in the FLCN gene, passed on so that an affected parent gives each child an even chance of carrying it. It produces small skin-colored bumps around the face and neck, thin-walled cysts in the lungs that make sudden lung collapse likely, and a raised risk of kidney tumors that are frequently multiple and on both sides.
What are the skin bumps?
They are fibrofolliculomas, small dome-shaped growths of a hair follicle together with the connective tissue wrapped around it. They appear as pale or skin-colored papules a few millimeters across, scattered over the face, neck and upper trunk, and they accumulate slowly through adult life. They are benign and cause nothing beyond their appearance, but because they are so characteristic they are often the finding that puts a name to the family.
Why does a lung collapse?
The lungs of someone carrying the fault contain thin-walled air pockets, usually sitting low in the chest and close to the midline. The wall of one can give way without warning, letting air escape into the space around the lung so that it deflates. The event tends to arrive in early adult life, often repeats, and is not connected to smoking or to emphysema. Between episodes, breathing tests are usually normal and there is no breathlessness, so the cysts are silent until one fails.
What is the true cancer risk?
| Site | What develops | Consequence |
|---|---|---|
| Skin | Benign follicle growths | Appearance only |
| Lungs | Thin-walled cysts | Repeated sudden lung collapse |
| Kidneys | Slow-growing tumors, often several | Long-term imaging surveillance |
| Colon | Polyps described in early reports | Association never confirmed |
The kidney risk is real and is the reason the diagnosis is worth making. Tumors tend to be of unusual types, grow slowly, and appear in several places in both kidneys, which shapes how they are watched and removed. The colon cancer link, by contrast, came from a small number of early families and has not held up in larger series, so it is no longer counted among the features. The inherited fault disables folliculin, a protein that helps cells judge how much energy and nutrient they have before committing to grow.
Also known as
Used in a sentence
Birt-Hogg-Dube syndrome was considered after a second spontaneous lung collapse in a young adult with facial papules.
Good to know
The lung cysts and the sudden collapse they cause are frequently the first sign and bear no relation to smoking, while the colon cancer association reported in early descriptions has not been confirmed by later study.