Familial intracranial aneurysms. Six cases among 13 siblings

Interactions of interleukin-12A and interleukin-12B polymorphisms on the risk of intracranial aneurysm

Several lines of evidence indicate that inflammatory processes play pivotal role in the development of intracranial aneurysm (IA). Recently, polymorphisms in the interleukin-12 (IL-12) gene were shown to be associated with immune-mediated inflammatory disease. The aim of this study was to investigate the interactions of IL-12A and IL-12B polymorphisms on the risk of IA in a Chinese population. A total of 422 individuals (including 164 patients with IA and 258 controls) were involved in the study. The polymorphisms (i.e., rs2243115 and rs568408 in IL-12A and rs3212227 in IL-12B) were genotyped by polymerase chain reaction-restriction fragment length polymorphism assay and DNA sequencing. We found an association of the AC/CC genotypes and C allele of IL-12B rs3212227 with an increased risk of IA, compared with the AA genotype and A allele (AC/CC vs. AA: OR = 2.09, 95 % CI: 1.29-3.38; C vs. A: OR = 1.45, 95 % CI: 1.10-1.91). Moreover, a significant gene interaction of IL-12A and IL-12B was evident on the risk of IA, and subjects carrying variant genotypes of IL-12B rs3212227 had an increased risk of IA. In the stratified analysis by gender, the IL-12B rs3212227 AC/CC genotypes had an increased risk of IA compared with the AA genotype in male patients (AC/CC vs. AA: OR = 4.63, 95 % CI: 1.92-11.16). These findings suggest that the IL-12A and IL-12B independently and jointly be involved in the susceptibility to IA.

Genetics Of Intracranial Aneurysms

Despite advances in the treatment of intracranial aneurysms (IA) in recent years, the overall outcome of patients with aneurysmal subarachnoid hemorrhage has shown only modest improvement. Given this poor prognosis, diagnosis of IA before rupture is of paramount importance. Currently, there are no reliable methods other than screening imaging studies of high-risk individuals to diagnose asymptomatic patients. Multiple levels of evidence suggest that environmental factors acting in concert with genetic susceptibilities lead to the formation, growth, and rupture of aneurysms in these patients. Epidemiological studies have already identified aneurysm-specific risk factors such as size and location, as well as patient-specific risk factors, such as age, sex, and presence of medical comorbidities, such as hypertension. In addition, exposure to certain environmental factors such as smoking have been shown to be important in the formation of IA. Furthermore, substantial evidence proves that certain loci contribute genetically to IA pathogenesis. Genome-wide linkage studies using relative pairs or rare families that are affected with the Mendelian forms of IA have already shown genetic heterogeneity of IA, suggesting that multiple genes, alone or in combination, are important in the disease pathophysiology. The linkage results, along with association studies, will ultimately lead to the identification of IA susceptibility genes. Identification of the genes important in IA pathogenesis will not only provide novel insights into the primary determinants of IA, but will also result in new opportunities for early diagnosis in the preclinical setting. Ultimately, novel therapeutic strategies based on biology will be developed, which will target these newly elucidated genetic susceptibilities.

Mapping a Mendelian form of intracranial aneurysm to 1p34.3-p36.13

The identification of pathways that underlie common disease has been greatly impacted by the study of rare families that segregate single genes with large effect. Intracranial aneurysm is a common neurological problem; the rupture of these aneurysms constitutes a frequently catastrophic neurologic event. The pathogenesis of these aneurysms is largely unknown, although genetic and environmental factors are believed to play a role. Previous genomewide studies in affected relative pairs have suggested linkage to several loci, but underlying genes have not been identified. We have identified a large kindred that segregates nonsyndromic intracranial aneurysm as a dominant trait with high penetrance. Genomewide analysis of linkage was performed using a two-stage approach: an analysis of ~10,000 single-nucleotide polymorphisms in the 6 living affected subjects, followed by the genotyping of simple tandem repeats across resulting candidate intervals in all 23 kindred members. Analysis revealed significant linkage to a single locus, with a LOD score of 4.2 at 1p34.3-p36.13 under a dominant model with high penetrance. These findings identify a Mendelian form of intracranial aneurysm and map the location of the underlying disease locus.

Anticipation and phenotype in familial intracranial aneurysms

BACKGROUND

In familial intracranial aneurysms there is evidence for genetic heterogeneity, probably from mutations at separate loci.

OBJECTIVES

To compare demographic and clinical features in patients of families with familial intracranial aneurysm and different patterns of inheritance; and to compare the ages of patients with subarachnoid haemorrhage (SAH) in affected parent-child pairs to determine whether there is anticipation.

METHODS

Pedigrees for 53 families with familial intracranial aneurysms were constructed, divided into patterns of inheritance suggestive or not suggestive of autosomal dominant transmission. Demographic and clinical features were compared. The age at time of SAH in affected parent-child pairs was compared using the Wilcoxon test.

RESULTS

No differences in demographic or clinical features were found between families compatible with an autosomal dominant pattern of inheritance and those with a non-dominant pattern. In families with affected members in two successive generations the age at time of SAH in parents was 55.2 years and in children 35.4 years (mean difference, 19.8 years, p<0.001).

CONCLUSIONS

Phenotypes are similar in families with and without a probable autosomal dominant pattern of inheritance. Thus in future genetic studies on familial intracranial aneurysms, stratification according to phenotype is not likely to be useful. Anticipation probably occurs, as affected parents are significantly older at the time of SAH than their affected children.

Anticipation in familial intracranial aneurysms in consecutive generations

Intracranial aneurysms (IA) are the major cause of subarachnoid haemorrhages (SAH). A positive family history for SAH is reported in 5-10% of the patients. The mode of inheritance is not unambiguously established; both autosomal dominant and recessive modes have been reported. In sporadic as well as in familial SAH, approximately 60% of the SAH patients are female. Recently, anticipation has been described in familial SAH. Since up to 15% of the SAHs are not caused by an IA, we have analysed anticipation, sex ratio and mode of inheritance only in families with patients with a proven IA in two consecutive generations. A total of 10 families were studied in which at least two persons in consecutive generations were affected by SAH, a symptomatic IA (SIA) or a presymptomatic IA (PIA). We also analysed published data from families with a proven IA in two consecutive generations on age of SIA onset and sex ratios among affected family members (both SIA and PIA). The age of SIA onset in the parental generation (mean 55.5 years) differed significantly from the age of onset in their children (mean 32.4 years). In the parental generation 11 men and 37 women were affected (both SIA and PIA), in the consecutive generation these numbers were 28 men and 32 women. There is a significant difference in sex ratio of affected family members when the generations are compared (P<0.02). No family could be found in which three consecutive generations were affected by an IA (SIA or PIA).

Elastin polymorphism haplotype and intracranial aneurysms are not associated in Central Europe

BACKGROUND AND PURPOSE

The occurrence of intracranial aneurysms and of aneurysmal subarachnoid hemorrhage are influenced by genetic factors. Recent genomic studies in Japan have defined 3 chromosomal loci and 1 haplotype of elastin polymorphisms as important risk factors, both for affected sib pairs and sporadic patients.

METHODS

We have genotyped 2 single nucleotide polymorphisms in the elastin gene and evaluated their allelic association with intracranial aneurysm in a Central European sample of 30 familial and 175 sporadic patients and 235 population controls.

RESULTS

We found no allelic association between this elastin polymorphism haplotype and intracranial aneurysm.

CONCLUSIONS

Our data probably reflect increased genetic heterogeneity of intracranial aneurysm in Europe compared with Japan.

Influence of smoking, hypertension, and sex on the phenotypic expression of familial intracranial aneurysms in siblings

OBJECTIVE

To investigate the effects of smoking, hypertension, and sex on the phenotypic expression of familial intracranial aneurysms (FIAs).

METHODS

We retrospectively reviewed the case records of 806 consecutive patients undergoing aneurysm surgery at our institution (1986-1995) and discovered 24 families with at least two affected siblings. Prevalence rates for the smoking, hypertension, and sex risk factors in these nuclear families were compared with those of patients with sporadic intracranial aneurysms (SIAs) and population-based control patients.

RESULTS

Affected family members with FIAs exhibited prevalence rates of smoking and hypertension (74% and 43%, respectively) that tended to be higher than those of population-based control patients (52% [P < 0.005] and 36% [P = not significant (NS)], respectively) and comparable to those of patients with SIAs (64% [P = NS] and 40% [P = NS], respectively). A positive association existed between FIA formation and female sex but was somewhat less strong than that observed in the SIAs (59% FIAs, 71% SIAs, 50% control patients). In addition, the prevalence rates of smoking, hypertension, and female sex were higher in affected family members with FIAs than in their unaffected siblings (58% [P < 0.05], 28% [P = 0.06], and 39% [P < 0.05], respectively). Individuals in families with expressed FIAs who had high aneurysmal penetrance had a greater tendency to be smokers, hypertensive, and female (74%, 59%, and 55%, respectively) than did their low-penetrance counterparts (61% [P = 0.1], 27% [P < 0.05], and 45% [P = NS], respectively).

CONCLUSION

Together these data suggest that hypertension, smoking, and female sex increase the likelihood that a member of a family with an expressed FIA will have an aneurysm. These observations may prove helpful in guiding the use of screening studies and encouraging education about the potential risks of continued tobacco use and untreated hypertension in this patient cohort.

Management of a ruptured cerebral aneurysm in infancy. Report of a case of a ten-month-old boy

A ten month old unconscious boy with hemiplegia (Hunt and Hess IV) was first admitted to a district hospital without a CT scanner or a neurosurgical service (Glasgow-Coma-Score 4, no pathological pupillary signs). Therefore, he was transferred to the Pediatric Department of the University Hospital the same night. An emergency CT scan that night showed intracerebral and subarachnoid hemorrhage with enlarged ventricle (Fisher grade 5). Angiography was not available within reasonable time. Thus in the stage of progressively increasing clinical deterioration, still without pupillary signs, an external ventricular drain-age was placed. Immediately after reduction of the cerebrospinal fluid volume, arterial hypertension was noticed--the right pupil was mydriatic and fixed. Without further apparative diagnosis an emergency craniotomy was performed for decompression under the suspicion of a secondary hemorrhage due to a rerupture of a middle cerebral artery aneurysm. A bleeding aneurysm of the right middle cerebral artery was found and clipped. A mass transfusion was necessary and a pulmonary air embolism occurred. The infant died in tabula. The histological specimens revealed disruption of the internal elastic membrane of both MCA. This emphasizes a congenital nature of the aneurysm. We conclude that cerebral arterial aneurysms have to be considered in the differential diagnosis of stroke-like symptoms in infancy and early childhood, although the incidence of reported cases is less than one case per year. Since no valid screening parameter is available, diagnosis is often made only after rupture of the aneurysm. This causes problems for emergency management. Infants and children with stroke or stroke-like symptoms should immediately be transferred to a hospital with a neurosurgical unit.

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, an independent risk factor for atherogenesis, has been demonstrated in sporadic IA disease (1). The purpose of this study was to assess the degree of correlation between elevated Lp(a) levels and the occurrence of IAs in asymptomatic first degree relatives of index cases from three families exhibiting a familial tendency towards IA development.

METHODS

25 family members and 41 healthy controls were screened by random serum Lp(a) sampling. All family members received 4-vessel cerebral angiography.

RESULTS

Eleven family members were found on angiography to 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 this 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 subjects with aneurysms compared with 22.1 +/- 1.45 mg% in subjects without demonstrable aneurysms and 10.5 +/- 0.48 mg% in the control population.

CONCLUSION

The prevalence of elevated Lp(a) levels in these families and the high degree of association of raised Lp(a) levels with the presence of IAs in several family members warrants follow up of angiographically negative young subjects. We require a case-control study to establish whether particular polymorphisms at the apoprotein (a) gene level are associated with the occurrence of IAs in these families.

Is family history an independent risk factor for stroke?

OBJECTIVE

To estimate the influence of family history on the occurrence of stroke.

METHODS

A case-control study was carried out from August 1992 to January 1994. The study population comprised 502 patients with a first stroke, aged between 20 and 70 years, who were treated at 48 affiliated hospitals. The same number of age and sex matched controls were selected from outpatients. Diagnoses were based on CT findings and clinical signs. There were 155 case-control pairs for subarachnoid haemorrhage, 158 for intracerebral haematoma, and 159 for cerebral infarction. Information about the patients and their families was obtained from a questionnaire which included the family histories of each subtype of stroke and other potential risk factors for stroke. The data were analysed focusing on the role of the family histories in the occurrence of stroke.

RESULTS

In univariate analysis, the family histories of subarachnoid haemorrhage and intracerebral haematoma were positively associated with each of the subtypes of stroke (odds ratios 11.24 for subarachnoid haemorrhage, 2.39 for intracerebral haematoma), whereas family history of cerebral infarction was not a significant risk factor for its occurrence (odds ratio 1.41). Family history of intracerebral haematoma was correlated with a personal history of hypertension and habitual alcohol consumption. After adjustment for potential risk factors (hypertension, diabetes, hyperlipidaemia, obesity, alcohol consumption, and regular smoking), family history of subarachnoid haemorrhage still remained the most powerful risk factor for subarachnoid haemorrhage, whereas family history of intracerebral haematoma no longer showed a significant association with haematoma.

CONCLUSION

Genetic factors play a major part in the pathogenesis of subarachnoid haemorrhage, and family history of subarachnoid haemorrhage is the strongest independent risk factor for the disease. On the other hand, family history of intracerebral haematoma was not an independent risk factor for haematoma, but it might be a good predictor, which indirectly influences the pathogenesis of intracerebral haematoma via certain hereditary components such as hypertension, and even lifestyle factors such as alcohol consumption. In cerebral infarction, genetic factors play a minor part in its pathogenesis.

Giant intracranial aneurysms in two sisters: case report

BACKGROUND

It is rare for intracranial aneurysms to present with cranial nerve palsy caused by the space-occupying effect of the lesion. Herein we discuss two sisters with familial intracranial aneurysms, both of whom presented with cranial nerve palsy.

CASE DESCRIPTION

Two female siblings presented with ocular movement and facial sensory disturbances caused by the space-occupying effect of giant aneurysms at the cavernous portion of the internal carotid arteries. The aneurysms were located at the identical site in both patients. Proximal occlusion of the internal carotid artery was effective in both cases, resulting in the promotion of thrombosis within the aneurysms in order to reduce their space-occupying effect.

CONCLUSION

This is considered to be the first known case of siblings, both suffering from giant internal carotid artery aneurysms.

Familial cerebral aneurysms: a study of 13 families

Despite the recent interest in familial cerebral aneurysms, the epidemiology, natural history, pattern of inheritance, screening of asymptomatic relatives, and the search for a biochemical marker remain problematic. To assess these issues, we report the results of our prospective study of 30 patients with 38 aneurysms (27 ruptured) and of the angiographic screening of asymptomatic relatives, all from 13 families seen consecutively since 1986. Women were over-represented (77%), and patients with multiple aneurysms (17%) were under-represented, compared with sporadic cases. Only 16% of the aneurysms were at the anterior communicating artery. Aneurysms occurred at the same or at the mirror site in 10 of 16 siblings (62%) and in 50% of mother-daughter pairs versus 20% for randomly selected, sporadic aneurysm patients. Rupture occurred in the same decade in 10 of 12 siblings (83%) versus the expected 21% for randomly selected, sporadic aneurysms. The average age at rupture was 47.2 years, and 60% of patients with a ruptured aneurysm were 50 years of age or younger. Seventy percent of patients died or were disabled from aneurysmal rupture. Screening of 41 individuals, including 2 dizygous twins, identified 1 aneurysm and 2 infundibula. A specific pattern of inheritance could not be ascertained from the pedigrees. The presence of an aneurysm was not associated with a specific human leukocyte antigen haplotype or antigen, and collagen Type III was qualitatively and quantitatively normal. Until a biological marker is identified, angiographic screening by intra-arterial digital subtraction or magnetic resonance angiography remains the only way to identify patients at risk of harboring a familial cerebral aneurysm.

On the inheritance of intracranial aneurysms

BACKGROUND AND PURPOSE

The familial occurrence of intracranial aneurysms suggests the presence of a genetically determined underlying arteriopathy. The pattern of inheritance in these families usually is not known.

METHODS

A family with seven members with intracranial aneurysms is described and, from the literature before 1994, a total of 238 families with 560 affected members (56% female and 44% male) with intracranial aneurysms not associated with a known heritable disease are reviewed. A segregation analysis was performed on 73 of these families.

RESULTS

Two members were affected in the great majority of families (79%); five or more members were reported in only eight families (3%). The most common affected kinship was among siblings. Angiographic screening in 12 families detected an intracranial aneurysm in 29% of 51 asymptomatic relatives. Segregation analysis revealed several patterns of inheritance that were consistent with the compiled pedigrees, but no single mendelian model was the overall best fitting, suggesting that genetic heterogeneity may be important. Twenty-two percent of siblings of male probands had an intracranial aneurysm compared with 9% of siblings of female probands (P = .003).

CONCLUSIONS

Genetic heterogeneity may be important in the genetics of intracranial aneurysms. In families with intracranial aneurysms, siblings of an affected male proband may be at a higher risk of developing an aneurysm than siblings of an affected female proband. Screening for intracranial aneurysms in asymptomatic relatives should be considered in families with two or more affected members. In most families, the nature of the underlying arteriopathy remains obscure.

Angiographic screening and elective surgery of familial cerebral aneurysms: a decision analysis

Up to 6% of cerebral aneurysms may be familial. Because the pattern of inheritance and the prevalence of aneurysms within families are unknown, the management of family members at risk of harboring a cerebral aneurysm is currently empirical. We established the prevalence of aneurysms in the second generation of individuals with familial cerebral aneurysms and determined the possible benefit of angiographic screening and elective surgery of such individuals by using a simple decision analysis model. Four consecutive families were identified in whom the mother and a child had a ruptured cerebral aneurysm. A total of 19 siblings at risk in the second generation were identified. Fifteen underwent elective cerebral angiography: one had a cerebral aneurysm and two had an infundibulum at the origin of the posterior communicating artery. Including the previously known aneurysms, the prevalence of aneurysms in the second generation was thus established at 29.4%. A decision analysis was performed with 2% as the annual risk of rupture, 72.7% as the risk of death or disability with rupture, 0.1% as the risk of angiography, and 6.5% as the risk of surgery. The benefit in years of survival free of sequelae resulting from angiographic screening and elective surgery (intervention) over natural history was computed for life expectancy corresponding to each quinquennial age group from age 15 to 100 years. Intervention equaled natural history, in terms of years of survival expected with each choice, at a life expectancy of 10.6 years, corresponding to age 76.5 years for men and 80 years for women, and produced a net gain of at least 1 year for patients whose life expectancy was 32 years or more, corresponding to age 53.5 years for women and 49 years for men. Greater benefit was achieved with increasing life expectancy (younger age). The prevalence of aneurysms in the second generation when a mother and child have an aneurysm is 29.4%. Intervention produces a benefit of at least 1 year of survival free of sequelae over natural history in such individuals if their life expectancy is 32 years or more.

Impaired in vitro proliferative response of suppressor lymphocytes in patients with subarachnoid haemorrhage from ruptured intracranial aneurysm

Proliferative response to mitogens concanavalin A, phytohemagglutinin and pokeweed mitogen, and other chosen indicators of the activity of the immune system were assayed in peripheral blood mononuclear cells isolated from blood of patients with subarachnoid haemorrhage from ruptured aneurysm. Healthy blood donors served as control group. The SAH group displayed impaired response to concanavalin A, which is a mitogen specific for suppressor cells. It is suggested that the impaired activity of suppressor cells pre-existed in patients with subarachnoid haemorrhage, and after intracranial bleeding it might have contributed to the development of late neurological deficits.

A probably familial saccular aneurysm of the anterior communicating artery in a neonate

A 32-day-old boy died of recurring cerebral hemorrhages starting on the 4th day of life. Autopsy disclosed a remittingly ruptured saccular aneurysm of the anterior communicating artery. A 7-day-old brother of his had previously died of recurring subarachnoid hemorrhages as well. The young age of the patient, the site of the aneurysm, and its probably familial occurrence make this case a unique one. Nonaneurysmatic basal cerebral arteries showed remarkable histological changes partly resembling those seen in fibromuscular dysplasia, some of them probably representing preaneurysmatic alterations. A known underlying systemic disease could not be found, and immunohistochemical detection of type III collagen revealed no identifiable deficiency.

[Intracranial saccular aneurysm: report of 3 cases in a same family]

The authors report the cases of three patients from the same family, all with intracranial saccular aneurysm (left carotid artery, anterior communicating artery, and middle cerebral artery). All three patients were operated on with good recovery and no complications. The authors call attention for some etiopathogenic aspects of familial saccular aneurysms.

Screening for unruptured familial intracranial aneurysms. A decision analysis

Decision analysis is used to assess the decision to screen for unruptured intracranial aneurysms (IAs) in two affected families, and to formulate guide-lines for similar decisions. Four strategies are compared: "no screening", "screening directly", "screening twice", and "screening later". Intravenous and intra-arterial digital subtraction angiography techniques (iv-DSA, ia-DSA) are considered. Life years lived with and without disability are computed for each strategy. Loss of life expectancy with and without discounting and quality correction is used as an outcome measure. "No screening" is the preferred strategy when population based estimates of the prevalence of IAs are used. Thus, the results of this analysis provide no justification for screening patients without a familial history. But a physician who thinks that the risk of an IA is increased may rightly decide for screening, especially when the patient is aged 40 to 60. Ia-DSA is preferable over iv-DSA. A scenario analysis suggests that screening with magnetic resonance angiography is only slightly better than with ia-DSA, because the complication rate of screening plays a minor role in the analysis.

Cerebral berry aneurysms in identical twins: a case report

A pair of identical twins in whom cerebral berry aneurysms were found is reported. One presented with epilepsy, and the aneurysm was discovered incidentally. The other presented with a spontaneous bleed, which was fatal.

Familial intracranial aneurysms. A review

BACKGROUND

A familial occurrence of intracranial aneurysms is defined by the presence of such aneurysms in two or more first to third-degree family members. Families with two affected members may represent accidental aggregation. Other families show a frequency compatible with an autosomal dominant mode of inheritance. A genetic basis is also suggested by the younger average age of familial cases with a ruptured intracranial aneurysm (42.3 years versus an age range of 50-54 years for nonfamilial cases), occurrence at the same site or a mirror site in sibling pairs, occurrence in identical twins, and the association of intracranial aneurysms with genetically transmitted disorders.

SUMMARY OF REVIEW

No reliable data are available about the occurrence of familial intracranial aneurysms among all patients with ruptured aneurysms; a frequency of 6.7% has been reported from a retrospective study, but a large part of the "familial" occurrence can be explained by fortuitous aggregation. The pathogenesis of familial intracranial aneurysms is not fully explained; a (partial) deficiency of type III collagen has been reported in sporadic, but not in familial, cases. Clinical decision analysis shows how the risk of harboring an intracranial aneurysm and the age of the patient are the main determinants for elective screening; lifetime risk of rupture (and therefore age) and surgical risks are the determinants for neurosurgical treatment.

CONCLUSIONS

Surgical treatment is recommended for patients aged less than 70 years with a moderate or low surgical risk, and screening (preferably by intra-arterial digital subtraction angiography) is recommended only for relatives aged 35-65 years. Magnetic resonance angiography may develop into a useful alternative for screening, but the risks of diagnostic procedures play only a minor role in the decision analysis.

HLA antigens and intracranial aneurysms

The frequencies of the HLA-A, -B and -DR were determined in a group of 59 transplant donors who died from subarachnoid haemorrhage within three days following the rupture of intracranial aneurysm (the SAH group) and compared with those of a control group consisting of 389 donors who died from other causes. The only significant difference was in the increased frequency in the SAH group of non-typed ("empty")-DR loci in association with the DR7 phenotype. The most probable explanation of this finding is that in the SAH group the frequency of DR7 homozygotes is several times higher than in the general population, and that bearing the DR7 allele in homozygotic form is associated with a very high risk of developing potentially fatal intracranial aneurysmal haemorrhage.

Pattern of subarachnoid haemorrhage in Saudi Arabia

It has often been claimed that subarachnoid haemorrhage (SAH) is a rare condition in the Middle East. A 7-1/2-year retrospective study was undertaken to substantiate or disprove this claim. It was found that although the condition is less common than the global average, it was not as rare as previously supposed. The pattern of distribution throughout the population, in terms of sex, was significantly different. The possible reasons for this are discussed.

Cerebral haemorrhage and berry aneurysm: evidence from a family for a pattern of autosomal dominant inheritance

Although families with several members suffering a cerebral haemorrhage have been reported previously, a family history of this stroke sub-type has not yet been firmly established as a risk factor for the disease. A family in whom cerebral haemorrhage has been clearly documented in five members, spanning three generations, is reported. In three a berry aneurysm was detected. There was no evidence of hypertension among any of the five cases. A sixth member of the family probably died of a cerebral haemorrhage but no necropsy was performed. By using established incidence rates for cerebral haemorrhage in the population, the probability of five such unrelated events arising in any family of similar size and longevity was calculated to be 4.9 x 10(-10). This family strengthens the case that an underlying genetic susceptibility does exist for a proportion of patients who have a cerebral haemorrhage. This susceptibility appears to be consequent upon berry aneurysm formation. The distribution of cases within this family is consistent with an autosomal dominant pattern of inheritance.

Screening for unruptured asymptomatic intracranial aneurysms in patients undergoing coronary angiography

In screening for unruptured asymptomatic intracranial aneurysms, an intracranial intra-arterial digital subtraction angiography (IA-DSA), posteroanterior view, was obtained in 72 consecutive patients who underwent coronary angiography for workup of angina pectoris. In cases where an aneurysm was suspected from IA-DSA, conventional intracranial angiography was obtained. Five asymptomatic unruptured aneurysms were detected in four of these cases. The aneurysms ranged from 4 to 16 mm in diameter. There were no complications associated with the coronary angiography nor with the additional intracranial IA-DSA, which required less than 5 minutes to perform in all cases. The value of performing intracranial IA-DSA in patients undergoing coronary angiography to screen for unruptured asymptomatic aneurysm is discussed, as is the possible racial differences in the frequency of aneurysms.

Models of arterial aneurysm: for the investigation of pathogenesis and pharmacotherapy--a review

Arterial aneurysms continue to provide a clinical challenge for neurosurgeons and vascular surgeons. Many different animal models have been developed in which the pathogenesis, growth, rupture and treatment of these aneurysms can be investigated. These animal models have been reviewed here, with the focus on saccular aneurysms in the muscular cerebral arteries and fusiform aneurysms in the elastic aorta. Consideration of the animal models described indicates appropriate experimental models and new directions for the development of improved models in which to test the effects of pharmacologic factors in limiting the growth and rupture of aneurysms.

Familial intracranial aneurysms: report of five families

Five families are reported in which 13 members suffered aneurysmal subarachnoid haemorrhage. The presentation of five of these patients in a 12-month period suggests that familial aneurysms may be more common than previously reported. The clinico-pathological features of these patients are reviewed with reference to previously reported families. The putative roles of dietary factors, Type III collagen deficiency, smoking, oral contraceptive ingestion and hypertension in the aetiology of familial aneurysms are discussed.

HLA-typing in a family with six intracranial aneurysms

The pedigree of a family where three of nine siblings had suffered from aneurysmal subarachnoid haemorrhage (SAH) was explored, by means of interviews and revisions of population and medical records. We thus found two nephews with previously ruptured intracranial aneurysms. Subsequently high resolution computerised tomography (CT) scans were performed in the remaining six siblings, one of which was shown to harbor an intracranial aneurysm. This individual was subjected to uncomplicated clipping of the aneurysm. Typing of human leukocyte antigen (HLA) was performed in 15 individuals of the pedigree. Three of the six HLA-antigens recently reported to occur in increased frequently in a series of (non-familial) patients with ruptured aneurysm were found, namely B7, DR2 and Cw2. Most noteable was the expression of the antigen B7 in five of the six individuals with aneurysm in the investigated family. At present HLA-typing is not a useful screening tool to identify individuals in the general population with an increased risk of developing intracranial aneurysms. The present study shows that HLA-typing could neither be used to predict the occurrence of intracranial aneurysms in the siblings in the investigated family. HLA-typing may provide further clues to our understanding of the etiology of intracranial aneurysms, especially concerning possible genetic factors. The authors thus would like to encourage HLA-typing in previously known and newly detected families with accumulation of intracranial aneurysms.

Multiple intracranial aneurysms in identical twins

Familial intracranial aneurysms are well documented, with the highest association occurring among siblings. Five pairs of identical twins with subarachnoid hemorrhage have been previously reported. We present the sixth set of identical twins with multiple aneurysms. These cases represent the first report in the literature of multiple mirror aneurysms in identical twins. One twin presented with subarachnoid hemorrhage. Her sister, who was asymptomatic, had elective angiography which demonstrated multiple aneurysms in locations identical to her sister's aneurysms. In families in which a twin presents with subarachnoid hemorrhage, it is appropriate to recommend angiography to the asymptomatic twin.

Aneurysmal subarachnoid hemorrhage in a child with leukemia

A child with acute lymphoblastic leukemia presented with an aneurysmal subarachnoid hemorrhage. The rationale for aggressively investigating leukemic children with headache and isolated oculomotor nerve palsy is outlined.

Giant aneurysms of bilateral internal carotid arteries in a child

Aneurysms in the petrous or cavernous portion of the internal carotid artery in childhood are extremely rare. Only two such cases have been previously reported. We present a case of bilateral giant intrapetrous aneurysms in a young female. CT was especially helpful in evaluating the absolute size of these aneurysms. This case is unique in that we demonstrated the temporal evolution of internal carotid aneurysms on follow-up angiography.

Detection of unruptured familial intracranial aneurysms by intravenous digital subtraction angiography. Screening of two affected families

The authors discuss the detection of intracranial aneurysms (IA) by means of intravenous digital angiography (ivDSA) in (a)symptomatic first degree relatives of families in which two or more individuals have IA. ivDSA is an almost noninvasive and low-risk diagnostic procedure. Screening, by means of ivDSA, of two affected families is described. In family I which includes 7 members with proven IA, ivDSA has been carried out in 36 asymptomatic individuals: in one, a 6 X 15 mm aneurysm was found at the left posterior communicating artery (PCoA). In family II, including one member with a proven IA and another with a subarachnoid hemorrhage, ivDSA has been carried out in 4 members: one aneurysm with a diameter of 6 mm was found at the left PCoA. Conventional cerebral angiography (CCA) confirmed both IA's. Neurosurgical treatment followed. The advantages and disadvantages of ivDSA vs. CCA as elective screening procedure in such cases are discussed. Screening of asymptomatic first degree relatives of cases with familial IA by means of ivDSA is strongly advocated.

HLA antigens and complement types in patients with intracranial saccular aneurysms

The occurrence of HLA-A, -B, -C antigens and the HLA controlled complement factors (Bf, C2, C4) was investigated in an unselected group of 116 consecutively admitted patients with intracranial saccular aneurysms, and compared to that of healthy controls (blood donors). When multiplying the p-values with the number of comparisons made, none remained significant. However, a rather high etiologic fraction of the BfS gene (0.59) was obtained. Moreover, for HLA -B7 a significant deviation from the Hardy-Weinberg equilibrium with an increase of homozygotes was found. Due to linkage disequilibria this could indicate a strong association between HLA-DR2 and saccular aneurysms. The presence of HLA-DR2 was therefore investigated in a series of 15 aneurysm patients used as cadaver kidney donors and not included among the 116 consecutively admitted patients. In this group the HLA-DR2 antigen frequency was significantly increased (66.7% vs. 29.7%, p less than 0.01). The present study thus demonstrates an association of saccular aneurysm and the major histocompatibility complex and shows the existence of a genetic predisposition to saccular aneurysm.

Multiple intracranial aneurysms: determining the site of rupture

A retrospective hospital chart and radiograph review was performed of all patients with multiple intracranial aneurysms seen over a 52-month period. Sixty-nine patients with a total of 205 aneurysms were studied. Among the patients with aneurysms, the incidence of multiple aneurysms was 33.5%. Multiple aneurysms were much more common in women, with a female to male ratio of 5:1 for all patients and 11:1 for patients with three or more aneurysms. Common locations for multiple aneurysms were the posterior communicating artery (22%), middle cerebral artery (21.5%), anterior communicating artery (12%), and ophthalmic artery (11%). However, locations with the highest probability of rupture were the anterior communicating artery (62%), posterior inferior cerebellar artery (50%), and basilar artery summit (50%). The middle cerebral artery was the least likely site for rupture. In contrast to previous studies, in this series irregularity of contour was more important than size in identifying the site of rupture. Using a simple algorithm outlined in the text, it was possible to identify the site of aneurysm rupture in 97.5% of cases.

Multiple cerebral aneurysms associated with left-sided inferior vena cava and hemiazygos continuation: a case report

A case of multiple saccular cerebral aneurysms in association with a left-sided inferior vena cava and hemiazygos continuation is presented. To our knowledge, this association has not previously been recorded in the literature.

Subarachnoid haemorrhage in identical twins

A pair of identical twins both of whom died of subarachnoid haemorrhage from ruptured anterior communicating artery aneurysms are reported. These twins are compared to the three other reported twins with ruptured cerebral aneurysms.

Familial intracranial aneurysm and infundibular widening

We present details of a family who show a high incidence of both intracranial saccular aneurysm and infundibular widening. Familial aneurysms are compared with aneurysms occurring in the general populations with regard both to site distribution and age of onset of symptoms. The possibility of infundibular widening being preaneurysmal is further discussed. It is highly likely that the mode of inheritance in familial cases is one of dominance.

Polycystic kidney disease and intracranial aneurysms. Early angiographic diagnosis and early operation for the unruptured aneurysm

From August, 1981, to August, 1982, the authors performed four-vessel angiography in 17 patients with polycystic kidney disease (PKD) who had no neurological deficit and no history of subarachnoid hemorrhage. Seven cases of unruptured aneurysms were found among these 17 patients (an incidence of 41.2%). Five of the unruptured aneurysms were operated on prophylactically, with no mortality or morbidity. Nine of the 17 patients had hypertension and, of these, two (22.2%) had aneurysms. Of the eight patients without hypertension, five (62.5%) had aneurysms. This study suggests that the coexistence of PKD and intracranial aneurysms might not be due to the hypertension that occurs concomitant with PKD, but instead may be attributable to congenital factors. The authors stress the necessity of early diagnosis and early operation for unruptured aneurysms in patients with PKD.

Familial intracranial aneurysms: report of four families

The authors describe eight cases of familial intracranial aneurysms occurring in four families. In the literature reviewed, familial aneurysms have different characteristics in that the incidence of the anterior communicating aneurysms is lower and that of the middle cerebral aneurysms is somewhat higher, and the age of patients at diagnosis is often younger. Although the number of patients is few, our study does not support these characteristics. A family history of intracranial aneurysms should include such high-risk factors as polycystic kidneys, coarctation of the aorta, fibromuscular dysplasia, and other connective tissue disorders.

Familial intracranial aneurysms. Case report

A case with two intracranial aneurysms is presented. The situation is unique because the patient was one of 13 siblings, seven of whom are now known to have harbored such aneurysms. The patient, now deceased from rupture of her aneurysm, was one of the two siblings who had previously refused elective angiography.

Familial occurrence of multiple intracranial aneurysms. Case reports and review of the literature

The authors report a family in which two members had multiple intracranial aneurysms. This is the third reported family with more than one member affected by multiple cerebral aneurysms. The congenital nature and the patterns of inheritance of the disease are discussed. The indications for elective investigation of the asymptomatic relatives are surgical prophylaxis on asymptomatic aneurysms are also briefly discussed.