There are likely different factors responsible – genetic and environmental- but the causes of FMD are still not clear and are the subject of ongoing intensive research.

Genetics

The study of genetic aspects is being addressed both by genealogical analysis and basic research.
Genealogical analysis is made possible by studying the data collected via the FMD registries (US and European). It shows that only a minority of patients ( 1.9 – 7.3%) report a family member diagnosed with FMD.
Basic research is looking for genes responsible for FMD. To date, no genetic tests specific to FMD have been found.

The study of the genetic aspects has important clinical repercussions:

(1) To date, when a patient is diagnosed with FMD, there is no justification to screen other family members unless they present suggestive symptoms of the disease
(2) There are currently no genetic tests specific to FMD

Environmental factors

Smoking has been identified as a potential factor in the development of FMD, among FMD smokers an earlier diagnosis of hypertension and a higher rate of aneurysms was seen. Stopping smoking is therefore strongly recommended in patients with FMD.

The role of female hormones is suggested by the higher number of women diagnosed with FMD.
However, there is currently no firm evidence that oral contraceptives, HRT (menopause treatment) or pregnancy increase the chances of developing or the progression of the disease.

Other possible causes may be related to abnormalities in the development of the small vessels that supply the artery walls, repeated stretching of the renal artery or kidney mobility but the implication of these mechanisms has not been confirmed so far.