For users of the COSMIC database or other clinical databases
following the recommendations from the Human Genome Variation Society
(HGVS)
The Human Genome Variation Society (HGVS) recommendations, which pertain to
variants within genes, state that for insertions and deletions in homopolymeric or repetitive regions, the most 3' position (corresponding to the strand of the gene)
possible should be arbitrarily assigned as the site of change (see http://www.hgvs.org/mutnomen/recs-DNA.html#del).
Resources such as COSMIC adhere to these recommendations. In this case, placement to the farthest possible left hand position,
as viewed in the Biomedical Genomics Workbench, of insertions or deletions in repetitive or homopolymeric tracts, has a different effect,
depending on whether the gene involved is on the positive or negative strand of the reference.
Such variants located within genes on the negative strand can be compared with the COSMIC database,
while those within genes lying on the positive strand cannot be, as the positions relative to the reference will be different in this case.