Little Justin Allen swiped a finger across the top of his white-frosted cake and took a lick. He got a sweet taste of his first birthday cake.

It was an especially sweet taste of life considering he almost didn’t live to see his

birthday at all.

Justin was born with a hole in his heart and a narrow valve, along with an irregular heartbeat. The condition is called transposition of the great arteries, a defect where the arteries are reversed.

The aorta receives oxygen-poor blood from the right ventricle, but the blood is sent back to the organs without getting more oxygen from the heart. The pulmonary artery receives oxygen-rich blood from the left ventricle, but carries the blood back to the lungs.

If not caught early, babies born with this defect can die from lack of oxygen.

But doctors at Vaughan Regional Medical Center spotted the telltale signs.

After he was born, they saw immediately that he was not getting enough oxygen.

“The whole nine months I was pregnant, I had no idea (the baby had this condition),” said Marie Allen, Justin’s mom. “I thought everything was fine. It was a routine C-section.”

The newborn baby was bundled up for a whirlwind few days.

First, he took an airplane flight to UAB Hospital, and then later to Children’s Hospital Boston for complicated open- heart surgery.

Marie, with the stiches from her surgery still throbbing, flew with the baby to Boston while her husband Shannon stayed behind with the couple’s four other children.

“I was stuck between a rock and a hard place,” Shannon said. “I was worried about my wife and baby, but I also had to take care of the other kids. My wife kept in constant contact with me, so I always knew what was going on.”

Justin underwent a nine-hour surgery to repair his heart. The arteries were reversed, and oxygen-rich blood began to flow through his body, with low-oxygen blood going back to the lungs for replenishing.

“I turned 30 the day of his surgery. That was one birthday I’ll never forget,” Marie said. “The whole time, I just sat in the waiting room praying and crying and saying ‘I’m scared, I’m scared.’ The nurses called me Mrs. Cry because I cried so much.”

Doctors said the surgery was successful.

It was a long road to recovery. Now Justin is continuing to exceed doctors’ expectations.

He is walking and learning a few words, including “momma.”

“He still has a heart murmur,” Marie said. “I have to take him to the doctor once a month. In June, he’s going to have a catheter put in to measure his heart rhythm and check to see if he has a blocked valve.”

The long-term outlook for children born with transposition of the great arteries depends on how bad the defect was before surgery, according to the American Heart Association.

Doctors say Justin needs to stay under a close medical watch for the rest of his life, to make sure his problems don’t return.

“I blamed myself for Justin’s heart condition,” Marie said. “I don’t know what caused it. I did everything right during the pregnancy. The doctors told me that (the defect) is hard to catch on an ultrasound.”

Now that a year has passed, the Allen’s say they are grateful for the doctors who saved his life and the many people who prayed for their family.

“I was just talking to my husband the other day about how fast this year has gone by,” Marie said. “Thinking about what we’ve been through, it made me want to cry all over again.”