In 2006, Hudson Sundgren came into the world a healthy infant with no indication of the severe medical journey he would endure with his parents, Chris and Wendy Sundgren, and Jackson, his brother.

He was 18 months old when he was diagnosed with mitochondrial disease, a genetic disorder in which specialized compartments in cells fail to create the energy the body needs to sustain and grow. Hudson had a form of the disease that affected his brain and muscles. It caused him to develop epilepsy, scoliosis and restricted lung disease. He was cortically blind, couldn't talk, but had a great smile.

Jackson Sundgren, his 9-year-old lacrosse-playing brother, adored him.

"We have always been open and honest with Jackson about Hudson," his father said. "He loved him and one of his Christmas requests was that he have the same brother without the disease. He was the best brother you could ask for."

On Thursday, Hudson Tyler Sundgren died from complications of restricted lung disease at his home in Cumming. He was 5. A memorial will be held at 11 a.m. Thursday at McDonald and Son Funeral Home & Crematory. The family asks that donations in their son's memory be made to the United Mitochondrial Disease Foundation.

Early on, the youngster babbled, rolled over, made eye contact, smiled and hit all the proper milestones. Around 1 year old, though, he started losing those skills and experienced "absent seizures."

"I would come home from work, go right up to him and there would be no eye contact, no recognition that anybody was there," his father said.

The seizures morphed into severe spasms in which his body would twitch, and progressed to the point his body would turn blue. Tests revealed he had some type of multifocal epilepsy all over his brain that had impaired his vision and slowed his ability to thrive. He was diagnosed with mitochondria in Oct. 2007.

Hudson had to ingest a special diet of high-fat whipping cream to bulk up, and pureed food as he got older. He was wheelchair-bound and eventually was placed on oxygen 24 hours a day. His health made family life a challenge, one the Sundgrens embraced.

"People would always say to us, ‘I don't know how you do it,' " his father said. "In our view, there were only two options: you either do or you don't. It was challenging for the family, but for us it's always been ‘do.' He has never been in daycare or someone else's care."

Lisa Higgins' daughter, 5-year-old Ainsley, suffers from a type of mitochondrial disease, too.  Four years ago, the Duluth mom started an annual fundraiser to benefit the United Mitochondrial Disease Foundation. She admires the care the Sundgrens provided Hudson.

"Their strength was amazing and they gave Hudson the best quality of life he could ever have," she said. "The medical stuff just became a part of who he was, but they never went through it thinking he's terminally ill."

Survivors besides his parents and brother include grandparents Gaylon and Audrey Wood of Conroe, Texas; and a great-grandmother, Lilla Swisher of Tempe, Ariz.