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Alyssa Tagua and her husband have two daughters with a hereditary disease called galactosemia.

After a few days of breastfeeding, her baby stopped eating. Alyssa discovered her firstborn daughter Brooklyn had the condition, a genetic disorder in which the body lacks an enzyme that focuses on how the body breaks down dairy products.

Breast milk or cow milk can be deadly for children who have it.

“As soon as milk is introduced into their diet which is the source of galactose so whether it be human milk, whether it be cow’s milk that rapidly increases the galactose level in their blood because they don’t have the enzyme to break it down,” said Dr. Israa Khan, a pediatrician with Community Health Network.

Both of the family’s daughters have the hereditary disease. Six-month-old Ava has a more severe case.

“If you were to give her a candy bar and she ate it she would be dead within three days because her body cannot process any of it whatsoever,” Alyssa said.

Symptoms include liver failure and developmental delays. If it’s not caught within the first two weeks of life it could be deadly. A newborn screening is the first line of defense to catch galactosemia.

“I thought it was just a useless screening it was just another test they wanted to do…Prick her and hurt her and had I not gotten it she would not be here,” Alyssa said.

It’s a lifelong illness that involves a strict dairy-free diet. And for Alyssa it meant doing away with her goal to exclusively breast feed.

“Every time we encourage breast milk which definitely we say is the best we forget at times that there are conditions there are certain babies who are born with a condition where it just cannot be done,” Khan said.

Now armed with knowledge from the newborn screening, Alyssa wants other parents to be aware.

“So don’t make assumptions that it’s nothing. If your motherly instinct is kicking in, do something and take action before it is too late,” Alyssa said.

This disease is very rare, affecting about 1 in every 60,000 newborns. Those newborn screenings are offered as soon as the child is born, and most babies with the condition are moved to a soy-based formula.