Familial cerebral cavernous malformation (CCM) exhibits autosomal dominant inheritance and is characterized by vascular disorders of the brain, which can lead to seizures, focal neurological deficits, hemorrhagic stroke, and migraine. Three CCM loci have been mapped, but the gene for only one locus--KRIT1 coding for Krev-1/rap1 interaction trapped 1 (KRIT1) protein, which is responsible for more than 40% of familial cases--has been identified. To date, a total of 72 mutations have been described, with one founder effect in the Mexican/Hispanic community. We report the case of an Italian family with CCM that has a novel KRIT1 gene mutation leading to a truncated KRIT1 protein. The protein truncation test (PTT) has been used as a rapid method of identifying germline mutations in the KRIT1 gene.