Sister Wives' Maddie Brown Brush Reveals Daughter Has Rare Condition Causing Limb Malformation

Emily Strohm

When Maddie Brown Brush went in for her routine ultrasound at 28 weeks pregnant, the Sister Wives star knew something was wrong.

“It usually takes about 45 minutes, but the doctor just kept looking and looking,” Brown Brush, 23, tells PEOPLE in this week’s issue, on newsstands Friday. “I was stressing out the whole time.”

Finally, after more than two hours, the doctor told her to meet him in his office. “That’s when he told me, ‘I can’t find all 10 fingers,’ ” she recalls.

At the time, Brown Brush’s unborn baby was diagnosed with oligodactyly, a congenital anomaly defined as the presence of fewer than five fingers on a hand. “There were lots of emotions,” she says, “but I was also relieved because there could have been a whole lot more wrong.”

But when the reality star and her husband Caleb Brush welcomed daughter Evangalynn Kodi on Aug. 20, the newborn was also missing a thumb and a toe, and one leg was missing a fibula (commonly known as the calf bone) and also had a bowed tibia (shinbone).

Hannah Hill photography
Maddie Brown Brush's daughter Evangalynn | Hannah Hill photography

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Additionally, two of her fingers were fused together. “We were shocked,” says Brown Brush, who is also mom to 2-year-old son Axel James. “I was just sitting there trying to comprehend what’s going on, having just had a baby as they are bringing in all these specialists. I was freaking out.”

Evangalynn was diagnosed with fibular aplasia, tibial campomelia and oligosyndactyly (FATCO) syndrome, an extremely rare genetic disorder that affects bone formation in utero. The cause is unknown. And because the disorder is so rare, it’s difficult to anticipate how Evangalynn’s future will look.

“How will she be at 70 years old? Will this come back and haunt her? There’s still a lot of unknowns, which is hard,” Brown Brush tells PEOPLE.

The family has to wait until Evangalynn turns 1 so that her body has more time to develop. At that time, they will consider options including surgery and amputation.

“There will be limitations, but not huge hindrances,” Brown Brush says, admitting she was initially hesitant to speak out about her daughter‘s condition.

She adds, “It’s abnormal, and it catches people off guard, but I want her to grow up and feel proud about who she is. If I’m hiding this to protect her, is it really helpful?”

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Brown Brush also wants to help others who may be dealing with the same issue. “So little is known about this, so I hope to bring awareness,” she says.

Sister Wives returns to TLC in early 2020.

For more from Maddie Brown Brush, pick up the latest issue of PEOPLE, on newsstands Friday.