Intracranial aneurysms, subarachnoid haemorrhage not linked to neurofibromatosis type 1
There is no evidence to support the association between neurofibromatosis type 1 (NF1) and intracranial aneurysms (IA), a new population-based study shows. Moreover, there is no rise in the incidence of aneurysmal subarachnoid haemorrhage (aSAH) in NF1 patients.
The prevalence of NF1 was analysed in 4,543 unruptured IA or aSAH patients and their 19,644 first-degree relatives from the Kuopio IA Database. Only those with either fusiform or saccular IA and diagnosed from 1969 to 2015 were included.
Conversely, prevalence of unruptured IA and aSAH was analyzed in 1,410 NF1 patients and 14,030 corresponding controls obtained from the national NF1 registry of Finland; controls were matched by age, sex and place of residence. From both databases, clinical information, including medications received and cause of death were retrieved and included in the analysis.
There were a total of 156 diagnosed conditions potentially related to NF1 in the IA cohort. Of these, only two were diagnosed with NF1; however, one was tuberous sclerosis misdiagnosed as NF1. There was only one confirmed NF1 case in the entire cohort resulting in a prevalence of 22 per 100,000 cases.
Five other individuals were suspected to have NF1. However, one presented findings that indicated schwannomatosis, two were confirmed to have NF2, two had symptoms more suggestive of NF2 and the last was diagnosed with leiomyoma instead.
In the NF cohort, and over a mean follow-up period of 15.0 and 16.3 years for the NF1 patients and matched controls, respectively, there was only one reported case of unruptured IA determined from autopsies. There were no cases of unruptured IA in the NF1 cohort and 19 cases in the controls.
There were five and 34 diagnosed cases of SAH in the NF1 patients and controls, respectively (hazard ratio [HR], 1.8; 95 percent CI, 0.69 to 4.67; p=0.234). On the other hand, only one NF1 patient presented with aSAH.