LIPOPROTEIN (A) - A POTENTIAL BIOLOGICAL MARKER FOR UNRUPTURED INTRACRANIAL ANEURYSMS

OBJECTIVE: The diagnosis and treatment of intracranial aneurysms (IAs) prior to rupture reduces the high morbidity and mortality associated with their occurrence. Elevated serum lipoprotein (a) [Lp(a)] level, a n independent risk factor for atherogenesis, has been demonstrated in sporadic IA disease (1). The purpose of this study was to assess the d egree of correlation between elevated Lp(a) levels and the occurrence of IAs in asymptomatic first degree relatives of index cases from thre e families exhibiting a familial tendency towards IA development. METH ODS: 25 family members and 41 healthy controls were screened by random serum Lp(a) sampling. All family members received 4-vessel cerebral a ngiography. RESULTS: Eleven family members were found on angiography t o harbour asymptomatic aneurysms and all were successfully treated by surgery. Of these 11, ten had significantly raised serum Lp(a) levels (>30 mg%). Fourteen family members had negative angiograms. Eight of t his latter group, mean age 43.6 +/- 3.8 years, had serum Lp(a) levels above the normal range. Mean Lp(a) levels were 53.7 +/- 1.2 mg% in sub jects with aneurysms compared with 22.1 +/- 1.45 mg% in subjects witho ut demonstrable aneurysms and 10.5 +/- 0.48 mg% in the control populat ion. CONCLUSION: The prevalence of elevated Lp(a) revels in these fami lies and the high degree of association of raised Lp(a) levels with th e presence of IAs in several family members warrants follow up of angi ographically negative young subjects. We require a case-control study to establish whether particular polymorphisms at the apoprotein (a) ge ne level are associated with the occurrence of IAs in these families.