CBS News/ June 28, 2012, 1:45 PM

Father's sudden death may give life to his twin girls

KHOU/Family photo / Glenna Harding Photography

(CBS News) Tyson Wallis wanted nothing more than to have a family with his wife Kristin. After trying several rounds of fertility treatments, including in-vitro fertilization, he got his dream in 2011 when his twin daughters Olivia and Eleanor were born premature at 33 weeks.

"I'll never forget the look on his face," Kristin told CBS affiliate KHOU in Houston, Texas. "He kept saying 'I finally have everything I've ever wanted.' It was just so perfect. It was really perfect. It was a great day."

Pictures: Dad's death shines light on rare Loeys-Dietz syndrome

But, Tyson was only able to enjoy family life for a brief time. On January 18, 2012 - 10 months after his daughters were born - he suddenly died at the age of 30. His untimely death, however, may lead to long and full lives for his twin girls.

Tyson passed away from complications due to Loeys-Dietz syndrome (LDS), an extremely rare connective tissue disease that affects the heart that he didn't even know he had. According to Loeys-Diez Syndrome Foundation, the genetic disorder is caused by gene mutation in either the TGFBR1 or TGFBR2 genes (transforming growth factor beta receptor 1 or 2). It manifests itself differently in all of its patients, so no two cases are alike. KHOU reported that only a few hundred people have been diagnosed with the disease.

Typical symptoms include widely spaced eyes and a split or broad uvula - the flesh that hangs in the back of the mouth. However it is the twisted or spiraled arteries and propensity for aneurysms caused by the disease that is most deadly for people. KHOU reports that the disease can also enlarge the aorta by stretching the aortic wall until it bursts, causing strokes and sudden death. On average, people with the disease usually only live until they are 26.

Specifically, Tyson suffered a rupture or dissection of an ascending aortic aneurysm.

"It's something that we could have prevented," Kristin explained to KHOU. "If we had known about it, they would have done surgery on my husband. And he could still be here. My daughters would still have their father. And I would still have my husband."

Because Tyson died from the disease, doctors knew to test his children. Both girls were diagnosed with LDS two months after their father's death.

"If this had to happen, maybe this is how we found out that we're going to save my daughters' lives. Because we never would have known about it," she said to KHOU. "I would never sacrifice my husband for my daughters, but he did save their lives."

Kristin wrote on her blog that people with LDS have a 50/50 chance of passing the disease on to their children. Preliminary tests revealed that both girls have a large aortic root and twisted arteries. Eleanor has at least two holes in heart that will require surgery before the age of 3. The girls will need to make sure they avoid activities that will over-stimulate their heart or increase their blood pressure. This means no caffeine, decongestants and chocolates. They will also have to restrict activity to avoid overexerting their hearts.

Kristin said on her blog that she was devastated that her children will have these health problems, especially since they will have to constantly be tested and live without their father. But, she does count herself lucky in several ways, especially since the girls were diagnosed so early. They can now live relatively normal childhoods.

"However, I know that I am blessed," she wrote. "Blessed to have an amazing support system of family and friends. I live within 30 minutes of the largest pediatric hospital in the world and have access to Dr. Dietz (the founder of the syndrome and primary research on the genetic testing) for the girls care. It is much easier to fight a battle when you know who your enemy is."