** Dyne Therapeutics' DYN.O shares down 12.6% premarket to $8.32, lowest since mid-Apr, after overnight follow-on priced

** Co, which focuses on neuromuscular diseases, late Mon said sold ~24.2 mln shares at $8.25 for $200 mln gross proceeds

** Offering priced at 13.3% discount to last sale

** It intends to net offering proceeds to fund ongoing clinical development of its product candidates, per the prospectus

** Also late Mon, Waltham, Massachusetts-based firm said it secured up to $275 mln in debt financing from Hercules Capital

** Morgan Stanley, Jefferies, Stifel and Guggenheim are jt bookrunners for the offering

** With ~113.7 mln shares outstanding, DYN has $1.1 bln market cap

** On Jun 17, DYN shares fell 21% to close at $10.86 after co revised timelines for its genetic disorder therapy following meeting with the FDA

** Through Mon, stock has shed ~60% YTD

(Lance Tupper is a Reuters market analyst. The views expressed are his own)

((lance.tupper@tr.com 1-646-279-6380))