This is truly a miracle.

Jeff Simms — the father of Leah Messer's first ex-husband, Corey Simms — revealed on Instagram that the former couple's daughter, Ali, is able to stay active despite her condition.

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Fans of Teen Mom 2 know that the seven-year-old, who has a twin named Aleeah, suffers from Titin Muscular Dystrophy.

"This pic is for those of you who prayed that Ali would walk. She played t-ball last season and softball this season. #prayerworks #aligrace #determination," Jeff wrote on Instagram.

According to the Joshua Frase Foundation, the condition is "a muscle disorder where muscle cells break down. Dystrophies generally result in weakness that gets worse over time."

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Last month Leah shared that even she gets emotional watching her twin daughters play softball together, considering Ali's illness.

"It was a moment I had to capture! Ali girl on second base and Aleeah on first. Watching them play softball together is so bittersweet!" she wrote on Instagram.

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“No matter what, I may never see the decline that they see. I guess I’ll handle that when it comes you know? It made it hard at 17, knowing something’s wrong with this baby that you love so f–king much,” Leah tearfully revealed in February on an episode of the MTV reality series.

Scroll through the gallery to see more photos of the Teen Mom stars with their kids!