The death of a boy with Duchenne muscular dystrophy, tied to a gene therapy, is above all a tragedy. But it is also undermining investor confidence in the company that makes it.

Cambridge-based Sarepta Therapeutics said it was halting shipments of its Duchenne muscular dystrophy gene therapy for patients who can no longer walk, following the death of a second person who received the treatment.

Sarepta Therapeutics (NASDAQ:SRPT) reported a second fatality from acute liver failure in a patient treated with its gene therapy, Elevidys, designed for Duchenne muscular dystrophy (DMD), Bloomberg News reported Sunday.