In a sample of 464 patients with acute ischemic stroke, the subgroup with ICAS (n = 236) showed a higher apoB/apoAI ratio (0.81±0.02) than both the subgroup with extracranial atherosclerotic stenosis (n = 44) (0.74±0.03) and the subgroup with no cerebral atherosclerotic stenosis (n = 184) (0.72±0.02) groups (P = 0.002). Here, APOB is linked to familial isolated congenital asplenia.