Almost from the beginning, Michele Kaplan knew something was amiss.

Her son Matthew’s childhood milestones – walking, talking – were delayed.

“We knew we had a developmental problem and after going to pediatricians and geneticists, he was finally diagnosed,’’ says Kaplan, 37, of Miami. “I don’t know what is scarier: not knowing what was wrong, or getting the diagnosis of such a rare syndrome.’’

Matthew, now 7, has Fragile X, a genetic syndrome that causes intellectual disability and is most commonly found in boys. The diagnosis sent Kaplan scrambling to seek treatment options and find other families in a similar position. She had little success. That scarcity of support and help in navigating the still-developing Fragile X world inspired Kaplan, along with another mother, to establish a foundation.

The Families for Fragile X foundation, now celebrating its fifth anniversary, has offered support for dozens of families with children diagnosed with the condition. To mark the anniversary, the non-profit foundation is hosting a fundraiser 5K trail run/walk Saturday at Virginia Key along with other activities for children.

“For parents dealing with Fragile X, it is difficult and a very long road. Often, they have already had concerns when the child is, say, 14 or 15 months, when they are already experiencing delays, but in so many cases, they are not diagnosed until they are 3 years old,’’ said Dr. Deborah Barbouth, director of the South Florida Fragile X Clinic, which currently serves about 60 families. “We know through research that early intervention can really help which is why education is so important.’’

Fragile X is the most common inherited cause of intellectual disability and the leading genetic cause of autism. An estimated 1 in 4,000 males and 1 in 8,000 females have the condition. Behaviors and characteristics include developmental delays, anxiety and hyperactivity, elongated faces and protruding ears.

So far, the foundation has raised more than $500,000 to aid in medical research and education, some of which benefits the South Florida Fragile X clinic, part of the University of Miami’s Miller School of Medicine. The foundation has provided 12 grants to needy families for evaluations at the clinic – each ranging from $500 to $2,500 -- one of first critical steps to addressing the condition. It has also sponsored educational conferences and pushed for early Fragile X screening.

“Fragile X is overwhelming in the sense that your world changes as you try to deal with the behavioral issues. That’s why it’s so important to have a strong support system,’’ said Kaplan, a wife and mother of three children. “We want to make it as easy as possible for families facing Fragile X.’’