Cerebral cavernous malformation (CCM) disease: from monogenic forms to genetic susceptibility factors.

Cerebral cavernous malformation (CCM) is a vascular disease of proven genetic origin, which may arise sporadically or can be inherited as autosomal dominant condition with incomplete penetrance and highly variable expressivity. CCM lesions manifest across a range of different phenotypes, including wide interindividual differences in lesion number, size and susceptibility to intracerebral hemorrhage (ICH), and may remain asymptomatic during the host's lifetime or result in pathological conditions of various type and severity at any age, with symptoms ranging from relatively minor (but still disabling) headaches through to very severe neurological deficits, seizures, and stroke. Currently, surgical removal of accessible lesions is the only direct therapeutic approach for CCM disease. However, whereas little information is available on the natural history of risk for patients to develop serious complications, such as ICH, prognostic biomarkers remain to be identified in order to ensure timely and optimal clinical decision making. In recent years, it has become clear that the three known CCM genes play an important role in controlling signalling pathways involved in cell responses to oxidative stress, pointing to a novel pathogenic mechanism whereby the function of CCM genes may be relevant in preventing vascular dysfunctions triggered by oxidative stress events. In turn, these novel findings have raised the possibility that genetic susceptibility factors related to differences in sensitivity to oxidative stress, including genetic polymorphisms, may contribute to interindividual differences in CCM disease susceptibility and severity. This review discusses recent progress toward the understanding of molecular mechanisms of pathogenesis and the identification of genetic susceptibility factors that could influence onset, progression and clinical severity of CCM disease, as well as consequent implications for the development of novel, safe and effective therapeutic strategies.