Aneurysms of the abdominal aorta: familial and genetic aspects in three hundred thirteen pedigrees.

Abstract

Familial clustering of abdominal aortic aneurysm was first noticed in 1977. Through questionnaire and phone inquiry, familial data on 324 probands with abdominal aortic aneurysms allowed the establishment of 313 multigenerational pedigrees including 39 with multiple affected patients. There were 276 sporadic cases (264 men, 12 women); 81 cases belonged to multiplex pedigrees (76 men; 5 women). We compared familial and sporadic male cases; the ages at diagnosis were 64.1 +/- 7.9 years and 66.0 +/- 7.3 years (p < 0.05), respectively, the ages at rupture were 65.4 +/- 6.6 years and 75.2 +/- 8.6 years (p < 0.001), and the rupture rate was 32.4% and 8.7% (p < 0.001). Survival curves were computed. Relative risk for male siblings of a male patient was 18. We performed a segregation analysis with the mixed model, the most likely explanation for occurrence of abdominal aortic aneurysm in our families was a single gene effect showing dominant inheritance. The frequency of the morbid allele was 1:250, and its age-related penetrance was not higher than 0.4. This analysis indicates the preeminence of genetic factors on multifactorial/environmental effects of the pathogenesis of abdominal aortic aneurysm.