I have identified some mutations in ESR1 gene through Sanger Sequencing. From initial analysis by looking at Ensembl, I see that those mutations are novel (Source mentioned in Ensembl is "dbSNP"). However, I want to check the novelty of these mutations in other mutations/variations databases. Could you please suggest me what other databases I could look at? And, how can I do this analysis of finding the novelty of the mutations I identified in the ESR1 gene in different databases?