Liyna Anwar, a podcast producer of South Asian descent whose struggle to find a stem cell donor to treat her cancer became the center of a social media campaign that aimed to make up for racial disparities in marrow and stem cell registries, died on March 26 in a hospital in Duarte, Calif. She was 30.

Her brother, Abbas Anwar, said the cause was complications of acute myeloid leukemia, the disease for which she had needed a stem cell transplant.

Stem cell and bone marrow transplants, critical treatments for blood cancers and other diseases, are far more likely to succeed when the recipient and donor are close genetic matches. When Ms. Anwar’s family sought a match for her, they found a dearth of potential minority donors registered. Among members of her family, her brother was the closest match, but still not an ideal donor for her.

A South Asian patient has about a 38 percent chance of finding a matching donor, considerably lower than white patients, who have about a 77 percent chance, said Kate McDermott, a representative of the nonprofit organization Be the Match, which manages the largest marrow registry in the world. Of 22 million registrants, she said, only 1 percent were of South Asian descent.