For some 15 years, Lani Nguyen bore the burden of knowing that her sons were likely to die before reaching adulthood.

Now, one by one, she has watched all three succumb to a rare genetic disease that attacked their immune system and left them weak and vulnerable to infection.

She had known since they were toddlers that the likelihood of them surviving was slim. But watching them suffer for most of their lives and then die within 2 1/2 years of one another tore at her heart.

Oldest son Tuan died in October 2006 at 17, and the disease claimed youngest son Anthony in December 2007 when he was just 15.

On Feb. 12, her second son, Kevin, died with his family at his bedside at Kapi'olani Medical Center for Women and Children. Kevin was 18 days shy of his 18th birthday.

"They were very sick and it was difficult," Lani Nguyen said as she tended to a shrine in memory of her sons at her Kukui Gardens apartment. "But I'm lucky that God took them home and there's no more pain. And they're together now."

Tuan, Kevin and Anthony suffered from Hyper IgM Syndrome, a genetic disease that is found in just one in more than 1 million children. The inherited blood disorder, which affects primarily boys almost immediately after birth, causes the body to produce an excess of some antibodies, but not enough of others.

Kevin and Anthony lived their entire lives fighting infections and illness and were in and out of the hospital. Tuan had the disease, but did not suffer from its symptoms until close to his death.

Dr. Wallace Matthews cared for the Nguyen boys for more than 10 years. He said the disease is so rare that a physician who specializes in the field may not treat a case in his or her career. For three brothers to have the illness is "even rarer," he said.

Matthews said he was amazed at the courage and strength displayed by Lani Nguyen through the ordeal. He called her an "absolute rock."

"I don't understand how you do that. I don't know how you bury three sons. I don't understand that at all," Matthews said. "There's some kind of strength there that most of us don't have. A lot of it comes from religion, but a lot of it comes from her inner core, her own personal strength."

IN 'TOTAL DESPAIR'

Four years ago, about 500 people turned out at seven bone marrow registry drives and the Nguyen family hoped that a donor could be found to provide a possible life-saving transplant.

But no match was found.

Nguyen said she was devastated when oldest son Tuan died because he had shown the fewest symptoms. At times, she said, she was in "total despair" and "wish- ed the world would end then."

Nguyen even questioned her faith.

"With deep sorrow and frustration, I asked myself, 'Why do my children have to carry this disease?' " she wrote in a prayer. "Every time I thought about their suffering, I could not hold back my tears."

But Nguyen said she found comfort and answers in her church, which helped her cope with her sons' disease. Still, it was difficult to watch as they became sicker and weaker.

"Many times Kevin was throwing up blood and my heart almost stopped," she said.

Nguyen said Kevin was hoping to get out of the hospital and spend his birthday, March 2, at home. But she said he couldn't fight the disease any longer.

"He was very sick," she said. "He was supposed to come home. He was coming up on his 18th birthday so that was something that he was looking forward to, and the family was looking forward to. He wanted a small get-together of his close friends and family, maybe have a dinner together."

Instead of planning a birthday dinner, Nguyen spent the past few days making funeral arrangements for the third time. She also was busy packing because she will be moving to a smaller apartment at Kukui Gardens with her husband of about 10 years and her daughter, Natalie, 12, who is healthy.

Nguyen said she's grateful to all of the people who helped her over the years, particularly the staff at Kapi'olani hospital, Make a Wish Foundation and the Hawaii Bone Marrow Donor Registry.

Roy Yonashiro, recruitment specialist at the registry, said he only wished that donors could have been found in time for the boys. Although nearly 500 people registered at the drives for the Nguyens, that wasn't enough to find a match.

Asians and other minorities are underrepresented in the national registry, he said. Of the 7.1 million people who have signed up, more than 70 percent are Caucasians.

But Yonashiro said he was encouraged by the concern and compassion expressed by the people who supported Nguyen and her sons. One of Kevin's wishes was that more people sign up for the registry so that others could be helped.

"What was a big plus was Kawananakoa Middle School. They came out in full force" during a bone marrow drive for the boys in 2004, Yonashiro said. "They remembered Tuan going to that school and Kevin and Anthony were still going to that school. They were out there waving signs and holding banners. I think it really cheered them (the brothers) up. If anything, it boosted their spirits to see their fellow classmates helping them."

Yonashiro said he was also touched by the appreciation that Lani Nguyen showed during such a trying period in her life.

"She's the sweetest person who was trying to do the best for her kids," he said. "It's such a nice family. Lani is so gracious to me and the registry staff and all the donors. She came out to thank all the people. As shy as she is, she's thanking people."

DIFFERENT STAGES

Lani Nguyen was pregnant with Anthony when the two older boys were diagnosed with the disease. Being a strong Roman Catholic and knowing there was a 50-50 chance that her baby could be born free of the illness, Nguyen had the child.

When the boys came to Matthews, they each were in different stages of the disease. Kevin was the sickest, Matthews said, while Tuan showed little signs of the illness.

"Tuan got sick very quickly at the end and passed away quickly, which was a blessing because until that time he was able to go to school regularly, he was able to do many things that other children could do," he said. "In some ways it was a good thing. He had a relatively good life and a rapid deterioration."

Although he was sick for most of his life, Kevin was the most outgoing of the three, Matthews said. He said he was always amazed at Kevin's positive outlook on life, despite the knowledge that he was going to die.

"He had a very optimistic attitude. He didn't let things bother him as much. He was much closer to the mother and to the family and was able to pass things off that might terrify other kids," Matthews said.

"It's a pretty terrible thing to watch both your brothers die before you of the same disease. I can't think of anything much worse."

The deaths of the boys touched Matthews and the hospital staff who cared for the brothers. Matthews said the hospital held a grief service Wednesday to help deal with the loss.

Working with the Nguyen family, Matthews said, the staff has learned a lot about life and the struggle to survive.

"This family has taught all of us a lesson in life, about suffering and dying and dealing with it," he said. "They've also taught us a lot about faith and resignation and acceptance. We medical people, we deal with death and dying a lot, but this family was unique."

COUNTING HER BLESSINGS

Last March, when Kevin was really struggling with the disease, he was presented with a medallion that symbolized his completion of a special program at McKinley High School. The medal is usually given to graduates, but family and school officials weren't sure if Kevin would live long enough to graduate with his class.

Lani Nguyen said the medal presentation was a proud moment in her son's life, as well as hers. But she was saddened because she will not see Kevin or his brothers achieve their dreams.

Tuan wanted to be a doctor, Kevin a cook and Anthony hoped to join the Army. All loved to play video games and the younger boys were always under the watchful eyes of big brother Tuan.

Although the boys were taken from her so young, Lani Nguyen said she cherishes the time she had with them.

"Since they were newborns, the doctor said they could have passed at any time, but they lived with me 17 years," she said. "I'm happy that I had those 17 years with them."