Table 2.

Phenotypes of interest in first degree relatives by family relation and sex. Arterial aneurysms and arterial dissections represent individuals with these findings consistent with DAAD, but not formal diagnoses of FMD. Phenotypes are mutually exclusive (for example, if a family member was diagnosed with FMD and was also known to have an arterial aneurysm, that individual would be counted as ‘FMD’ but not ‘Arterial aneurysm’. Suspected DAAD are clinical signs that may represent undiagnosed DAAD which included: stroke or transient ischemic attack at or before age 55, hypertension or antihypertensive medication requirement before age 30, renal artery stenosis in the absence of cardiovascular disease, and/or sudden unexplained death without clear etiology. All relatives are the sum of all first-degree relatives of probands, regardless of clinical status.

	FMD	Arterial aneurysms	Arterial dissections	Suspected DAAD	All relatives
Parent
F	2	3	1	6	72
M	0	12	1	6	72
Total	2	15	2	12	144
Sibling
F	4	4	1	5	91
M	0	5	1	7	94
Total	4	9	2	12	185
Offspring
F	5	1	2	0	64
M	0	1	0	6	70
Total	5	2	2	6	134
All First-Degree Relatives
F	11	8	4	11	227
M	0	18	2	19	236
Total	11	26	6	30	463

F, Female; M, Male