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.

Duchenne muscular dystrophy patient died after being treated with the gene therapy delandistrogene moxeparvovec (Elevidys), Sarepta Therapeutics said Sunday. Like the first case reported, this patient developed acute liver failure (ALF) that resulted in death.