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Cerebral cavernous malformations (CCMs) are vascular lesions of the CNS characterized by abnormally enlarged capillary cavities. CCMs can occur as sporadic or familial autosomal dominant form. Familial cases are associated with mutations in CCM1[K-Rev interaction trapped 1 (KRIT1)], CCM2 (MGC4607) and CCM3 (PDCD10) genes. In this study, a three-gene mutation screening was performed by direct exon sequencing, in a cohort of 95 Italian patients either sporadic or familial, as well as on their at-risk relatives. Sixteen mutations in 16 unrelated CCM patients were identified, nine mutations are novel: c.413T > C; c.601C > T; c.846 + 2T > G; c.1254delA; c.1255-4delGTA; c.1681-1682delTA in CCM1; c.48A > G; c.82-83insAG in CCM2; and c.396G > A in CCM3 genes. The samples, negative to direct exon sequencing, were investigated by MLPA to search for intragenic deletions or duplications. One deletion in CCM1 exon 18 was detected in a sporadic patient. Among familial cases 67% had a mutation in CCM1, 5.5% in CCM2, and 5.5% in CCM3, whereas in the remaining 22% no mutations were detected, suggesting the existence of either undetectable mutations or other CCM genes. This study represents the first extensive research program for a comprehensive molecular screening of the three known genes in an Italian cohort of CCM patients and their at-risk relatives. [ABSTRACT FROM AUTHOR]

Cerebral cavernous malformations (CCMs) are vascular lesions of the CNS characterized by abnormally enlarged capillary cavities that can occur sporadically or as a familial autosomal dominant condition with incomplete penetrance and variable clinical expression attributable to mutations in three different genes: CCM1 (Krit1), CCM2 (MGC4607) and CCM3 (PDCD10). Among our group of CCM Italian patients, we selected a cohort of sporadic cases negative for mutations in CCM genes. In this cohort, five variants in CCM2 gene were detected, which proved to be the known polymorphisms in intronic regions (IVS2-36A>G and IVS8 +119 C>T) and in coding sequence (c.157 G>A in exon 2, c.358 G>A in exon 4 and c.915 G>A in exon 8). Therefore, we undertook a case-control study to investigate the possible association of these polymorphisms with sporadic CCMs. The five polymorphisms were identified in 91 CCM sporadic patients and in 100 healthy controls by direct sequencing methods using lymphocyte DNA. Polymorphisms IVS2-36A>G and c.915 G>A showed statistically significant differences in frequencies between patients and controls [(χ2, 6.583; P<0.037); (χ2, 14.205; P<0.001)]. The prevalence of the wild-type genotype was significantly lower in the CCM group than in the control sample. Patients with the A/G and G/G genotypes (IVS2-36A>G) had a significant increase for CCM risk (OR, 3.08; 95% CI, 1.5-5.9 and OR, 4.3; 95% CI, 1.4-22.6) and the same was observed for the polymorphism c.915 G> A (genotype G/A OR, 6.1; 95% CI, 3.0-12.6 and genotype A/A OR, 2.79). In addition, the polymorphisms c.358 G>A in exon 4 (χ2, 15.977; P<0.04) and c.915 G>A in exon 8 (χ2, 18.109; P<0.02) were significantly associated with different types of symptoms. Haplotype analysis, performed only on polymorphisms c.358 G>A (p.Val120Ile), c.915 G>A (p.Thr305 Thr) and IVS2-36A>G, shows that haplotype GAG (+--) significantly increased among CCM sporadic patients compared to the control group. Significant differences between patients and controls were observed only for IVS2-36A>G and c.915 G>A polymorphisms indicating their possible association with sporadic CCMs and an increased risk of CCM. On the other hand, polymorphisms c.358 G>A and c.915 G>A were associated with a more benign course of the disease. These data were confirmed by the haplotype GAG (+--) frequencies.