A Nebraska woman born without a brain just celebrated her 20th birthday — and is defying the odds.

Alex Simpson of Omaha was born with a rare condition known as hydranencephaly, according to her parents, Shawn and Lorena Simpson, who spoke with local news outlet KETV News about the milestone.

“[Hydranencephaly] means that her brain is not there,” Shawn told the outlet. “Technically, she has about half the size of my pinky finger of her cerebellum in the back part of her brain, but that’s all that’s there.”

The family said that doctors told them their daughter would likely not live past the age of 4.

When asked why they believe Alex has lived so much longer than expected, both Shawn and Lorena said, “love.”

While Alex cannot see or hear, her parents say they believe she can sense their presence.

“You can see that when I went up there and talked to her a little bit ago, she was looking for me,” Shawn told the outlet, while mimicking Alex’s eye movements.

Shawn told the outlet that he credits “faith” with helping their family through Alex’s initial diagnoses — and beyond.

“Twenty years ago, we were scared but faith, I think, is really what kept us alive,” he said.

“She’s a fighter,” Lorena added.

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Alex’s 14-year-old brother, SJ, told KETV that he’s proud to have Alex as his sister.

“When people ask about my family, the first thing I start with is Alex, my disabled sister,” he said.

SJ went on to say that, like his parents, he believes Alex can perceive and intuit things happening around her.

“Say somebody’s stressed around her — nothing will even happen — it could be completely silent, but Alex will know. She’ll feel something,” he said.

Scientists estimate that hydranencephaly occurs in one in 5,000 to one in 10,000 pregnancies, and the condition is usually fatal within the first year of life, per the Cleveland Clinic.