** Shares of gene-editing firm Intellia Therapeutics NTLA.O down 60% to $61.02 premarket
** Co pauses patient dosing in late-stage trials of its experimental gene-editing treatment called nex-z in a type of protein buildup disease
** NTLA says pause follows severe liver side effects in one patient dosed in late-stage trial
** Co consulting experts and regulators on next steps - NTLA
** Over 450 patients estimated to have received nex-z so far, Co said
** Up to last close, stock down 120% YTD
(Reporting by Sahil Pandey in Bengaluru)
((Sahil.Pandey@thomsonreuters.com))