Though Mattituck resident Maren DeSantis copes daily with Rett Syndrome, a rare genetic neurodevelopmental disorder, her family is making sure she lives as full a life as possible.

Maren, now 13, was diagnosed with Rett Syndrome at 16 months. Wheelchair dependent, she has no use of her hands and is nonverbal. Still, as she’s grown up, her mother, Lena, has kept her involved in numerous activities, including therapeutic horseback riding, adaptive cross-country skiing, biking and hiking.

“I have to say that this world can be so isolating,” Ms. DeSantis said. “But then, at the same time, you get to witness all these people that really devote their lives to giving children like Maren, or adults, access to things. They don’t even think twice … that has been so humbling to experience and be a part of and I’m just so thankful.”

Rett Syndrome causes a progressive loss of motor skills and language, according to the Mayo Clinic. It affects approximately 6,000 to 9,000 people in the United States, according to Rett Revealed, an awareness campaign run by Acadia Pharmaceuticals, maker of the only FDA-approved medication currently available to treat the disorder.

Earlier this year, Maren participated in a crosscountry skiing excursion as part of a 10-episode docuseries produced by Rett Revealed called, “Magnolia’s Guide to Adventuring.” The series follows 13-year-old Magnolia Tesler of Wilton, Conn., who was diagnosed with Rett at age 3, as she embarks on various adventures with fellow patients and their families.

Magnolia’s father, AJ Tesler, was the project producer and filmmaker, and had previously produced “Magnolia’s Hope,” an award-winning documentary about his family’s journey with Rett.

“When my daughter was diagnosed, I started looking online for any kind of indication of what might happen to her … and I didn’t find a lot,” Mr. Tesler said. “So I started making videos online to share our story and share our triumphs and the things that were hard, in hopes of building a community and raising awareness to ultimately lead to treatments or a cure.”

Creating “Magnolia’s Guide to Adventuring,” he said, was a “natural next step to the things we had already been doing. We identified 10 different activities that we wanted to do, most of them we had already done with Maggie before, but part of the idea was to bring some other families along on these adventures with us.”

The complete docuseries depicts downhill and cross-country skiing, ice skating, horseback riding, ATV riding, swimming with dolphins and other outdoor pursuits. All 10 episodes are available at rettrevealed.com.

Ms. DeSantis and Jenny Tesler, Magnolia’s mom, didn’t meet in person until February, when they recorded their daughters’ episode in upstate Norwich, N.Y. However, they had connected online through a Facebook group for parents of children with Rett. That led to a text chain between them that ultimately resulted in Maren’s appearance in the docuseries.

“Even though we had never really met Lena before, Jenny and she really hit it off,” Mr. Tesler said. “Crosscountry skiing is actually something that they do regularly with [Maren] and we’d never been before, so it was actually an opportunity for their family to take us on an adventure — which was a nice little switch.”

Recalling Maren’s outing with Magnolia, Ms. De Santis said, “It was the most magical day. Last year, it didn’t really snow at all, but that morning there were huge flakes coming [down], no winds and everything was snowy … we met, and we skied for the day, and it was really fun.”

She added that the feedback to Maren’s episode of “Magnolia’s Guide to Adventuring” has been great and that most viewers have commented on the girls’ smiles.

“It’s been fun,” she said. “They were so smiley, both girls. I’d never met Magnolia before. I feel like she’s like a little celebrity but her smile is just so infectious and then just watching her and Maren together was so fun. It’s been very positive.”