CCM2/malcavernin

Cerebral Cavernous Malformations

Clinical Characteristics
Ocular Features: 

Cavernous capillary hemangiomas usually occur singly in the fundus, often at the disc.  Fewer than 5% of individuals with CCM have retinal lesions.  As opposed to the systemic hemangiomas, those in the eye tend to be stable.  However, they may result in vitreous hemorrhages because they lack the usual structural support of normal vessels.  Fluorescein angiography often reveals blood-fluid levels in the saccules that comprise the grape-like cluster of the tumor.

Systemic Features: 

Cavernous angiomas may involve any part of the CNS, brain stem, and spinal cord.  These are benign aberrant growths of capillary endothelium which develop shortly after birth and cause a variety of signs and symptoms including seizures, intracranial hemorrhage, and focal neurologic deficits. New lesions can appear throughout life. The blood –containing clusters are lined with endothelium only and the walls lack muscle or fibrous tissue.  Up to 25% are diagnosed in children. They may be angiographically silent but MRI is diagnostically useful.  Cutaneous hemangiomas are uncommon but helpful diagnostically when present.  The overlying skin may be hyperkeratotic.

Many patients (25-50%) remain asymptomatic throughout life.

Genetics

This is an autosomal dominant disorder caused by mutations in three genes.  CCM1 (116860) results from mutations in the KRIT1 gene located at 7q11.2-q21, the disease called CCM2 (603284) is caused by mutations in the CCM2/malcavernin gene (7p13), and CCM3 (603285) by mutations in the PDCD10 gene at 3q26.1.  The majority of familial cases have mutations in one of these genes.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

The fundus lesions seldom require treatment but photocoagulation can be used to seal those that lead to recurrent vitreous hemorrhages.  Embolism may be beneficial for CNS lesions but the lesions in many locations are relatively easy to remove surgically. Seizures are treated symptomatically.  Pharmaceutical agents that alter blood clotting should be administered with careful monitoring.

References
Article Title: 

Genotype-phenotype correlations in cerebral cavernous malformations patients

Denier C, Labauge P, Bergametti F, Marchelli F, Riant F, Arnoult M, Maciazek J, Vicaut E, Brunereau L, Tournier-Lasserve E; Soci?(c)t?(c) Fran?ssaise de Neurochirurgie. Genotype-phenotype correlations in cerebral cavernous malformations patients. Ann Neurol. 2006 Nov;60(5):550-6.

PubMed ID: 
17041941
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