Multiple intracranial aneurysms in identical twins

Concordant Symptomatic Intracranial Aneurysm in a Monozygotic Twin: A Case Report and Review of the Literature

The development of an intracranial aneurysm (IA) is a multifactorial process, involving genetic and environmental factors. The presence of IA or aneurysmal subarachnoid hemorrhage (aSAH) in twins is particularly interesting, since both genetic and environmental factors can be studied. It also raises the question of whether, when one twin is affected, the other asymptomatic twin should be examined for an IA. We report on a monozygotic (MZ) twin-pair with aSAH in both twins and we review all reported cases of IA in MZ twins. Including our case, we found only 14 MZ twin-pairs in which both twins harbored an IA, suggesting a heavy underreporting in the medical literature. In this small group, a high concordance was noted in the sites of IAs. In MZ twins, the preferred sites for IAs are the branching arteries, while aneurysms arising from fusion arteries are rare. These sites differ from the preferential sites seen in series of familial IAs and series of sporadic IAs. We therefore hypothesize that the twinning process might play a significant role in the development of IAs in MZ twins. To further explore and substantiate this, the large twin registries should be studied. Although IAs in MZ twins with a negative family history for IAs should not be regarded as familial IAs, screening of the asymptomatic twin should be seriously considered if one MZ twin presents with an aSAH or an IA, because of the high fatality rates reported in asymptomatic (and not screened) MZ twin-halves.

Diagnostic characteristics and management of intracranial aneurysms in children

Childhood aneurysms have special characteristics different from adults' aneurysms. Their features were found to significantly differ from aneurysms in adults especially in their gender prevalence, location, morphology and underlying etiology. Treatment options include both surgical and endovascular methods. Whenever possible, endovascular treatment for pediatric aneurysms is the recommended approach, since it offers both reconstructive and deconstructive techniques, durable results and better clinical outcome.

Familial Aggregation of Both Aortic and Cerebral Aneurysms: Evidence for a Common Genetic Basis in a Subset of Families

OBJECTIVE

Although previous reports have described patients with both cerebral and aortic aneurysms, any association was believed to be coincidental. In this study, we provide evidence that aortic and cerebral aneurysm formation may share a common genetic predisposition in some families.

METHODS

A prospective enrollment of consecutive patients treated for saccular cerebral aneurysm by a single surgeon was constructed. Medical and family histories were obtained. Familial syndromes were identified when two or more first-degree relatives had diagnoses of cerebral or aortic aneurysm. Pedigrees were constructed, and asymptomatic relatives were screened.

RESULTS

In 2.5 years, 274 patients were enrolled from 322 eligible patients (85%). A family history of aortic aneurysm was noted in 29 patients (10.5%). These patients were older, included more males, and were overwhelmingly Caucasian. Statistically significant demographic differences were noted when these families were compared with families affected by cerebral aneurysm only. A total of 110 affected family members were identified (average, 3.8 per family; range, 2-12); 59 had cerebral aneurysms, and 51 had aortic aneurysms. In some families, the association may have been coincidental. But in several families, pedigree analyses showed an inheritance pattern likely to represent autosomal dominance with variable penetrance. In addition, both cerebral and aortic phenotypes could be inherited from a parent with an aortic aneurysm, further evidence for a common genetic basis.

CONCLUSION

This study, which represents the largest and most complete characterization of families affected by both cerebral and aortic aneurysms, provides evidence that a single gene defect may lead to the development of either lesion.

Incidence of familial intracranial aneurysms in 200 patients: comparison among Caucasian, African-American, and Hispanic populations

OBJECTIVE

Although the cause of cerebral aneurysms remains unclear, there is clear evidence that genetic predisposition plays a role. Ten percent of patients report an aneurysm in a first-degree family member. However, studies to date have largely involved Caucasian populations. Our goal was to characterize the familial aggregation of intracranial aneurysms in different ethnic groups.

METHODS

We began a prospective, single-center study on patients treated for intracranial aneurysms. Consenting subjects completed a detailed questionnaire regarding the medical history of family members. In families with two or more affected members, asymptomatic first-degree relatives were screened using computed tomographic or magnetic resonance angiography.

RESULTS

In a 2-year period, 292 patients with intracranial aneurysms were treated and 200 were enrolled; these included 124 Caucasians (62%), 34 African-Americans (17%), 38 Hispanics (19%), and 4 Asian-Americans (2%). Forty patients had a family history (20%). The incidence of family history among the different ethnic groups was similar; it was 19.4% in Caucasians, 20.6% in African-Americans, and 21.6% in Hispanics. One Asian-American patient had a family history. Visual inspection of the pedigrees supported autosomal-dominant inheritance with variable penetrance in all ethnic groups.

CONCLUSION

This study examined the incidence of familial cerebral aneurysms in three ethnic groups common to the United States: Caucasian, African-American, and Hispanic. We noted an equivalent rate of familial aneurysms, a finding that has immediate clinical implications. In families that have two or more members with cerebral aneurysms, screening of asymptomatic members should be recommended, regardless of ethnic background.

What to do when the doctor sees double: identical twins with nearly identical aneurysms

SUMMARY

This report details the case of identical twins, both of whom had an aneurysm in the same anatomic location. Such aneurysms should be considered as a discrete subset of familial aneurysms. The implications for patient management are discussed.

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.

Intracranial aneurysms in identical twins

BACKGROUND

Though familial intracranial aneurysms are well documented, only a few cases of intracranial aneurysms in identical twins have been reported.

CASE REPORT

Our patient, a 46-year-old woman, presented with a subarachnoid hemorrhage (SAH) due to a ruptured aneurysm. At the age of 36, her identical twin sister had also suffered SAH from a ruptured aneurysm. Both twins were treated successfully.

CONCLUSION

The likelihood of the occurrence of an aneurysm may be higher for a twin whose identical twin has developed an aneurysm than for the general population. Therefore, it is reasonable to perform certain screening procedures for aneurysms on an asymptomatic twin when the other presents with SAH due to a ruptured aneurysm.

Genetics of stroke--a review

Evidence from twin and family shows that genetic factors contribute to the risk of stroke and that their role may be at least as important in stroke as in coronary heart disease. Additional support for the significance of genetic factors comes from other findings such as epidemiological data showing phenotypic heterogeneity of stroke, genetic influence on many of the risk factors for stroke, and racial and geographic differences in morbidity and mortality in stroke victims. Yet, apart from the reported associations of a small number of cases with Mendelian cerebrovascular diseases, only a few studies have directly investigated gene markers or molecular genetics of stroke. This review presents the existing evidence on the genetic background of stroke and discusses results from the genetic studies of stroke published to date.

Familial cerebral aneurysms

Familial cerebral aneurysms are currently the subject of burgeoning interest. We review the pertinent, recent reports on this topic in the light of our study of 17 families with familial cerebral aneurysms. The prevalence of familial cerebral aneurysms ranges from 5-28%. The sex distribution displays a female bias. Mothers are more often affected than fathers and daughters more than sons. There is no site predilection for familial cerebral aneurysms but they tend to occur at the same (or mirror) site within families. The age at rupture of familial cerebral aneurysms is younger, especially in females, than for sporadic aneurysms. They tend to rupture within the same decade in families, and within five years of each other in identical twins. The size of ruptured familial cerebral aneurysms appears to be smaller, especially in women, than sporadic aneurysms. The pattern of inheritance is unknown. A poor outcome of rupture is more frequent in familial cerebral aneurysms cases than in sporadic ones. Angiographic screening of family members at risk, especially first degree relatives, appears justified.

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 bias for women

BACKGROUND AND PURPOSE

We evaluated the influence of gender on the formation and rupture of familial cerebral aneurysms.

METHODS

We studied 30 patients with ruptured cerebral aneurysms from 14 consecutive families. These patients were compared with the patients with sporadic aneurysms reported by the first Cooperative Study.

RESULTS

Eighty percent of familial aneurysms occurred in women versus 59% of sporadic aneurysms (P < .05, chi 2 test). This overrepresentation of women occurred at below the age of 50 years, where 78% of patients with familial aneurysms were women compared with 45% for sporadic aneurysms (P < .01, chi 2 test). Above this age, there was no statistical difference in incidence of familial aneurysms in men or women compared with sporadic aneurysms. In women with familial aneurysms, rupture occurred before the age of 50 years in 59%, compared with 31% for sporadic aneurysms (P < .01, chi 2 test). In four of five families, aneurysms ruptured within 10 years of each other in sisters (mean, 6 years). Multiple aneurysms were equal in both groups (17%), but multiple familial aneurysms occurred mainly in women. There was no difference in the site of single cerebral aneurysms in either group, but familial aneurysms in females occurred at the same site in five of eight families (62%) and in 11 of 17 mother-daughter or sister pairs (65%), compared with 20% for two randomly selected sporadic aneurysms (P < .01).

CONCLUSIONS

There is an overrepresentation of women with ruptured familial aneurysms compared with those with sporadic aneurysms. Familial aneurysms rupture in females predominantly before the age of 50, in the same decade, and at the same site within families in the majority of cases. These observations support a possible genetic cause for cerebral aneurysms and a possible hormonal contribution to their rupture.

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.

A ten percent prevalence of asymptomatic familial intracranial aneurysms: preliminary report on 110 magnetic resonance angiography studies in members of 21 Finnish familial intracranial aneurysm families

The population in eastern Finland has been stable for generations, causing a high degree of genetic isolation and providing excellent possibilities for follow-up studies. Of 91 families with familial intracranial aneurysms, 21 were randomly selected for prospective magnetic resonance angiography studies for intracranial aneurysms. Sixteen intracranial aneurysms were detected in 11 asymptomatic family members of a total of 110 studied. The prevalence of intracranial aneurysms among these familial intracranial aneurysm families is 10%, approximately 10 times higher than in the average population. Our findings suggest that family members of familial intracranial aneurysm families should be examined for intracranial aneurysms. Familial intracranial aneurysm may be a genetic disorder.

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.

Monozygotic twins not identical with respect to the existence of intracranial aneurysms: a case report

The hypothesis that intracranial aneurysms are inherited is based on published accounts of aneurysms occurring in two or more members of the same family. This hypothesis has been strongly supported by rare cases of intracranial aneurysms in pairs of identical twins. Seven such pairs have been reported to date. In all pairs, both twins had intracranial aneurysms, most of them located at the same site. Only rarely did they appear at exact contralateral locations. In five pairs, both twins suffered from a subarachnoid hemorrhage (SAH). In one case, the asymptomatic twin underwent angiography and was treated before an SAH occurred. We now present the first pair of identical twins. One twin had an SAH and two intracranial aneurysms. The other was asymptomatic and showed no aneurysms with either three-dimensional magnetic resonance angiography or intra-arterial digital subtraction angiography. Based on epidemiologic data, we assume that there must be many unreported cases of identical twins with at least one twin suffering from SAH. Our case indicates that the trait of intracranial aneurysms is not inherited with complete penetrance, which might otherwise be assumed on the basis of all other accounts previously described in the literature. However, as long as the exact means of inheritance of intracranial aneurysms is not understood, we still recommend an angiographic examination of the asymptomatic identical twin in cases where the other sibling had already suffered from an aneurysmal SAH.

Familial subarachnoid hemorrhage in east Finland, 1977-1990

The familial occurrence of cerebral aneurysms in a defined clinical group of 1150 patients from a defined catchment area was studied. Two or more proven aneurysmal subarachnoid hemorrhage (SAH) patients within the same family were included. Of these 1150 patients, 113 (10%) had a proven familial occurrence of aneurysmal SAH. These 113 patients form 91 SAH families with a total of 203 aneurysm patients. Fifty-four percent of the patients were female, and the mean age in female patients was 49 years and in male patients was 44 years. In 23% of the families, three or more members were identified as having cerebral aneurysms. Middle cerebral artery aneurysms were the most common type (47%). Based on the high incidence (10%) of familial intracranial aneurysms among SAH patients, a prospective study of healthy family members for incidental intracranial aneurysms was performed, with positive findings of 12%.

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.

Familial association of intracranial aneurysms and cervical artery dissections

BACKGROUND AND PURPOSE

The familial occurrence of intracranial aneurysms and cervical artery dissections has been described in different families and supports the hypothesis that a primary arteriopathy may play a role in the pathogenesis of these disorders. Although the basis for this arteriopathy is generally not believed to be similar among cases of intracranial aneurysms and cervical artery dissections, several similarities exist in the epidemiology of these disorders and a common underlying arterial abnormality may be suspected.

SUMMARY OF REPORTS

The medical records of all 175 patients with spontaneous dissections of the cervical arteries who were seen at the Mayo Clinic between 1970 and 1989 were reviewed to identify families in which intracranial aneurysms and cervical dissections coexisted. Three families were identified in which intracranial aneurysms and cervical artery dissections were observed among siblings. These families are described in detail.

CONCLUSIONS

The familial occurrence of intracranial aneurysms and cervical artery dissections within the same families provides support to the importance of a common underlying arteriopathy in the pathogenesis of both these disorders. The underlying vascular defect may, at least in some cases, be inherited.

Multiple middle cerebral artery aneurysms in an infant. Case report

An 11-month-old boy was admitted for evaluation of drowsiness, vomiting, and convulsions. Computerized tomography showed subarachnoid blood in the left sylvian fissure and a small intracerebral hematoma in the temporal lobe. Angiography revealed several aneurysms of the left middle cerebral artery (MCA). During surgery, 13 aneurysms were found arising from one main branch of the left MCA, and this segment of the MCA was trapped. Somatosensory evoked potentials did not show any change during surgery. The diseased arterial segment was examined histologically and the pathogenetic aspects of the case are discussed. Control angiography 6 months later excluded systemic disease or other aneurysms. The rarity of such lesions in childhood and their successful surgical treatment are discussed briefly.