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.

Another person treated with Elevidys suffered acute liver failure, leading Sarepta to discontinue treatment in certain patients while it evaluates new safety precautions.

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.