ANEURYSMS OF THE ABDOMINAL-AORTA - FAMILIAL AND GENETIC-ASPECTS IN 313 PEDIGREES

Purpose: Familial clustering of abdominal aortic aneurysm was first no ticed in 1977. Methods: Through questionnaire and phone inquiry, famil ial data on 324 probands with abdominal aortic aneurysms allowed the e stablishment of 313 multigenerational pedigrees including 39 with mult iple affected patients. Results: There were 276 sporadic cases (264 me n, 12 women); 81 cases belonged to multiplex pedigrees (76 men; 5 wome n). We compared familial and sporadic male cases; the ages at diagnosi s were 64.1 +/- 7.9 years and 66.0 +/- 7.3 years (p < 0.05), respectiv ely, the ages at rupture were 65.4 +/- 6.6 years and 75.2 +/- 8.6 year s (p < 0.001), and the rupture rate was 32.4% and 8.7% (p < 0.001). Su rvival curves were computed. Relative risk for male siblings of a male patient was 18. We performed a segregation analysis with the mixed mo del, the most likely explanation for occurrence of abdominal aortic an eurysm in our families was a single gene effect showing dominant inher itance. The frequency of the morbid allele was 1:250, and its age-rela ted penetrance was not higher than 0.4. Conclusion: This analysis indi cates the preeminence of genetic factors on multifactorial/environment al effects of the pathogenesis of abdominal aortic aneurysm.