A boy with a rare and treatable "bubble boy" disorder who was saved by a test after his family lost an older sister to the disease is welcoming Ontario's newborn screening announcement for the illness.

Lori Peters and her eight-year-old, Ethan, travelled from Niagara-on-the-Lake, Ont., to join his sisters at the Children’s Hospital of Eastern Ontario in Ottawa today as Ontario Health Minister Deb Matthews announced a new life-saving screening for newborns in the province.

Healthy Ethan greeted Ontario health minister Deb Matthews after she announced newborn screening for SCID. (CBC)

"It saves lives," Matthews told reporters. "It saves money in the long run. With appropriate treatment they can be cured."

Ethan has Severe Combined Immune Deficiency or SCID, a group of rare and potentially fatal conditions in which the immune system either lacks key immune cells called T-lymphocytes or the cells don't work properly. It's also known as bubble boy disorder after David Vetter, a boy from Texas with a type of SCID, lived for 12 years in a plastic, germ-free bubble.

"The most frustrating part of losing our beautiful daughter was that she was never given a chance to fight," Peters said of their daughter, Brooklyn. "We never knew what we were fighting. We felt so helpless and lost."

Ontario is adding screening for SCID, or bubble boy disease, to its standard heel prick blood test for newborns. (J. Scott Applewhite/Associated Press)

Peters said Brooklyn had repeated bouts of pneumonia and hospitalizations. It was only when Brooklyn's final blood sample was sent to Toronto that she was diagnosed with SCID. "She had no immune system to fight even a simple cold," her mother said.

When Ethan was born, he spent eight months in hospital in reverse isolation until he received a bone marrow transplant.

Ethan is now 100 per cent healthy and medication free, his mother said. He presented Matthews with a large thank-you sign.

Since Aug. 12, newborns in Ontario have been undergoing screening for SCID during standard heel prick test bloods. Ontario is the first jurisdiction in Canada to include this test. In the U.S., several states have being doing it for a couple of years, according to the SCID internet homepage.

Infants with SCID appear healthy at birth, but develop severe infections within the first few months of life, such as pneumonia, meningitis or bloodstream infections, Newborn Screening Ontario said. Without treatment, SCID is fatal.

The treatment is a bone marrow or stem cell transplant. Enzyme replacements may also be given.

This new test is expected to save the lives of up to 10 babies each year, the province's health ministry said.

Matthews said it cost about $1 million to get equipment and training and will cost about $1 million a year to operate.