RASA1 analysis: clinical and molecular findings in a series of consecutive cases.

RASA1 mutations have been reported to be associated with hereditary capillary malformations (CM) with or without arteriovenous malformations (AVM), arteriovenous fistulas (AVF), or Parkes Weber syndrome. But the number of cases with RASA1 mutations reported to date is relatively small and the spectrum of phenotypes caused by mutations in this gene is not well defined. Mutation results and clinical findings in thirty-five unrelated consecutive cases sent for RASA1 molecular sequencing testing at ARUP Laboratories within the last two years were evaluated. Eight individuals had a pathogenic RASA1 mutation of which six were novel. These eight individuals all had CMs (seven had multifocal CMs; one had multiple CMs), and six also had a brain or facial AVM. Two individuals with multifocal CMs including one with a fast flow lesion had a variant of uncertain significance. All other individuals, including sixteen with CMs and one with a vein of Galen aneurysm, tested negative for a RASA1 mutation. Our data suggest that multifocal CM is the key clinical finding to suggest a RASA1 mutation. The clinical diagnostic mutation detection rate among all samples sent for RASA1 testing was 29% (10/35) which increases to approximately 39% (10/26) if patients without CMs are excluded.