First Report of Concomitant Pathogenic Mutations Within MGC4607/CCM2 and KRIT1/CCM1 in a Familiar Cerebral Cavernous Malformation Patient

Background Familial cerebral cavernous malformations (CCM) are among the most common vascular malformations of the central nervous system (CNS) and are linked to mutations on the specific genes CCM1/KRIT1, CCM2/MGC4607, and CCM3/PDCD10. We present the first report in the literature of a pharmaco-resistant epileptic patient harboring co-occurring pathogenic mutations within CCM2/MGC4607 and CCM1/KRIT1. Case Description A 51-year-old patient first presented at age of 33 years with episodes of seizures. Magnetic resonance imaging including a susceptibility-weighted imaging sequence had shown multiple cerebral cavernous malformation lesions. She had partial response of symptoms and remained in routine follow-up needing progressive pharmacological improvement. Direct sequencing allowed the detection of 1 nonsense pathogenic mutation in CCM2/MGC4607 (c.118C>T; p.Arg40Ter) and 1 unclassified frameshift insertion variant in CCM1/KRIT1 (c.1687_1688insT; p.Tyr563LeufsTer5). Conclusions Although the CCM2/MGC460 variant seems to be the major contributor for the patient’s CCM phenotype, the mutated CCM1/KRIT1 seems to act as a booster to CCM overall pathogenicity.