Tobacco use increases lesion burden in familial cerebral cavernous malformation syndrome

•There is a wide range of total T2 and large lesion T2 (≥5 mm) count in patients with familial or presumed familial cerebral cavernous malformation (CCM) syndrome.•Tobacco use in patients with familial CCM is associated with 5 or more large T2 lesion count.•Hypertension, Hyperlipidemia and Diabetes did not influence total T2 lesion count in patients with familial CCM. Background: Familial cerebral cavernous malformation (CCM) syndrome is characterized by multiple, non-contiguous cavernous malformations. The lesion burden may affect morbidity. Our aim was to identify risk factors for high lesion burden in these patients. Methods: Patients with radiologically confirmed CCM were screened between 2015 and 2023. Only familial or presumed familial CCM patients were included. Demographic information and medical history at the time of diagnosis were evaluated. The first diagnostic MRI was used to determine T2 total and T2 large lesion (≥5 mm) count. Chi-square was used to determine risk factors for total T2 large lesion count ≥5. Results: Of 107 patients with familial or presumed familial CCM (55.1 % female, age 42.4 years), the median total T2 lesion count and large lesion count was 4 (range: 1–109) and 2 (range: 0–50) respectively. Current tobacco use was a risk factor for T2 large lesion count ≥5. Conclusion: Further studies combining familial cohorts and assessing length of exposure may be useful to confirm tobacco as a risk factor for T2 large lesion formation in familial CCM.