An intracranial berry aneurysm that is characterized by rupture of an intracranial aneurysm, an outpouching or sac-like widening of a cerebral artery, leads to a subarachnoid hemorrhage, a sudden-onset disease that can lead to severe disability and death and that has_material_basis_in heterozygous mutation in the THSD1 gene on chromosome 13q14.