PCRE (Perl Compatible Regular Expression) for protein level alteration notation. Based on http://www.hgmd.cf.ac.uk/docs/mut_nom.html#protein

alteration-protein-level-pattern.re

(?x)
^
(?<prefix>p.)?
(?<alteration>
  (?:
    (?<substitution>
      (?<substitution_old>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
      (?<substitution_position>\d+)
      (?<substitution_new>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
    )
    |
    (?<deletion>
      (?:
        (?<single_deletion>
          (?<deletion_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
          (?<deletion_position>\d+)
        )
        |
        (?<range_deletion>
          (?<deletion_start_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
          (?<deletion_start_position>\d+)
          (?:_)
          (?<deletion_end_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
          (?<deletion_end_position>\d+)
        )
      )
      (?:del)
    )
    |
    (?<insersion>
      (?<insersion_start_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
      (?<insersion_start_position>\d+)
      (?:_)
      (?<insersion_end_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
      (?<insersion_end_position>\d+)
      (?:ins)
      (?<insersion_sequence>(?:A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)+)
    )
    |
    (?<indels>
      (?:
        (?<single_indels>
          (?<indels_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
          (?<indels_position>\d+)
        )
        |
        (?<range_indels>
          (?<indels_start_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
          (?<indels_start_position>\d+)
          (?:_)
          (?<indels_end_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
          (?<indels_end_position>\d+)
        )
      )
      (?:delins)
      (?<indels_sequence>(?:A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)+)
    )
    |
    (?<duplications>
      (?<duplications_start_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
      (?<duplications_start_position>\d+)
      (?:_)
      (?<duplications_end_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
      (?<duplications_end_position>\d+)
      (?:dup)
    )
    |
    (?<frame_shifting>
      (?<frame_shifting_start_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
      (?<frame_shifting_start_position>\d+)
      (?:fs)
      (?<frame_shifting_end_nucleotide>A|R|N|D|B|C|E|Q|Z|G|H|I|L|K|M|F|P|S|T|W|Y|V|X)
      (?<frame_shifting_end_position>\d+)
    )
  )+
)
$