The BHD (Birt-Hogg-Dubé) Syndrome autosomal DNA project is open to BHD patients and their blood relatives. The major goal is to use Family Finder test results to identify BHD patients who are (even very distantly) related to each other, as shown by having matching regions of DNA in the region where the FLCN gene is located. Once shared ancestors or lines are identified, this info may be helpful in identifying other descendants who have inherited BHD but have not yet been diagnosed. The project will also support extended families who have at least two diagnosed cases of BHD (who are not siblings or parent & child), and want to determine which other close family members inherited the mutation and which did not. For those with the symptoms who have had sequencing done but no FLCN mutation has been found, this method should still be able to identify which other family members inherited the FLCN allele associated with the symptoms --OR it may help identify a different gene associated with BHD-like symptoms in your family. Definitive diagnosis of BHD is based on showing the presence of a mutation by sequencing the FLCN DNA. The Family Finder test does NOT do this. What it can do is identify relatives who share matching segments of DNA --but this knowledge can be surprisingly powerful. Birt-Hogg-Dubé syndrome (BHD) www.bhdsyndrome.org/for-families/what-is-bhd/ is a group of symptoms or traits caused by deleterious mutations in the folliculin (FLCN) gene on chromosome 17. The syndrome is autosomal dominant (meaning you can show symptoms if you inherit a mutant copy of the FLCN gene from either parent, not necessarily both) with partial penetrance (meaning some people with an FLCN mutation will show no obvious symptoms). Because of the partial penetrance, and the fact that symptoms, even if present, don't usually become apparent until adulthood, it is difficult to trace which ancestors the mutant FLCN gene was inherited from. It is rare to find adults who can trace the mutation back beyond their grandparents. Similarly, when an ancestor (or parent) is known to have the mutation; unless the descendants (or children) show obvious symptoms, it's difficult to know who inherited the mutation and who did not. This project is intended to try to provide clues.