Elianna Constantino is doing what any other 4-month-old does: laughing, cooing and recognizing her mom, dad and 3-year-old brother.

You’d never know the Kauai infant has been fighting for her life, undergoing five blood transfusions and a bone marrow transplant even before she was born.

She is the first patient enrolled in a clinical trial involving blood stem cells transplanted in utero to potentially cure a fatal genetic disease known as alpha thalassemia major, which causes fetuses to develop anemia, heart failure and brain damage and, often, to be stillborn. The disease, carried mostly by Southeast Asians, restricts red blood cells from carrying enough oxygen throughout the body.

“The thought for us was babies just don’t survive,” said Elianna’s mother, Nichelle Obar, 40. “Being the mother looking at your daughter’s ultrasound and her enlarged heart working overtime, I thought, ‘She’s not going to make it.’”

That’s when the family found out about the first clinical trial to test the safety of a procedure in which a mother’s stem cells are transferred to a child through a vein in the umbilical cord. Elianna is the first of 10 patients in the study with the hope that the mother’s healthy cells will reproduce and replace the baby’s faulty ones, eventually curing the disease.

Elianna’s parents, Obar and Chris Constantino of Kilauea, are both Filipino and carriers of the disease. Thus, their children each have a 1-in-4 chance of having the condition. Their firstborn son, Gabriel, was “perfectly healthy.”

“It’s really important to get the word out in Hawaii” because of the large Asian population, said Dr. Tippi MacKenzie, lead investigator of the study at the University of California, San Francisco. “A lot of patients are told that there’s nothing that can be done. Fetal therapy can be lifesaving with just the blood transfusions even if it seems like the fetus is very sick and may not survive.”

The latest research indicates the mother and fetus tolerate each other’s cells during pregnancy, meaning “they’re not fighting off each other’s cells,” she said.

“That’s why we had to take cells from Elianna’s mother to put into Elianna when she was a fetus,” MacKenzie said. “Previously, there had been attempts to do this but not using what we now think is kind of the winning combination: using the mom’s cells and a huge dose of cells injected into the bloodstream. She’s doing amazingly well. It’s a chronic medical condition, but you can live a very meaningful life with this disease.”

Elianna must get blood transfusions every three to four weeks at a cost of roughly $50,000 a year — most of it covered by insurance. The bone marrow transplant costs about $150,000.

“There are a lot of diseases that can be cured with a stem cell transplant after birth, but stem cell transplants after birth are risky,” MacKenzie said. “You have to give a lot of medicines to prevent your body from fighting off the new cells that you’re putting in there. But if you can do it successfully in the fetus, then you could treat the disease before they’re born and not have to give all those toxic medicines.”

If successful, doctors could use the method to treat other hereditary diseases, including sickle cell anemia. If not, doctors are hoping Elianna can get another “booster” transplant of her mother’s cells later in life to cure the disease.

“We just take it day by day. Right now we don’t even know if it’s working,” Obar said. “(But) I’m happy. … She’s doing what a 3-, 4-month-old should be doing.”