The Loma Prieta earthquake during warm-ups for Game 3 of the 1989 World Series wasn't the most earth-shaking moment in former Oakland A's centerfielder Dave Henderson's life. Instead, it was the diagnosis of Angelman syndrome his son, Chase, received in 1987.

"It not only impacted my baseball career, it impacted my whole family," Henderson said in a phone interview from Seattle, his hometown. "I've had a son that has been disabled, so I've always had a better perspective. Baseball was a game, but not a top 10 priority."

Angelman syndrome (AS), first diagnosed by British physician Harry Angelman in 1965, is a neurogenetic disorder that causes severe developmental delays. Individuals with AS have intellectual and physical disabilities requiring lifelong care. Often misdiagnosed as cerebral palsy (CP) or autism, the battle to properly assess symptoms is arduous for families like the Hendersons.

"They tend to throw every kid with disabilities in a vat," Henderson said, recalling the almost two-year struggle he and his wife, Loni, fought to find a proper diagnosis. "CP is not a diagnosis you can give a guy like me. You look deeper and you get a specialist."

Eventually, a doctor at Seattle Children's Hospital confirmed that their son would walk a far different path than his famously devoted father. Henderson said his 28-year-old son "doesn't walk, talk, has seizures, is dependent on caregivers" and takes 12 medications each day. "I've been bathing, feeding and doing everything you do with someone who can't take care of himself," he said.

But that doesn't mean Henderson's hard-hitting days with the Seattle Mariners (1981-1986), Boston Red Sox (1986-1987), San Francisco Giants (1987), Oakland A's (1988-1993) and Kansas City Royals (1994) weren't glory-filled. Henderson stepped to the plate in five World Series; his years with the A's boosted his batting average and left him wearing a treasured World Series ring.

Anticipating the camaraderie of the 25th anniversary of the 1989 World Series Champion Oakland A's at the O.co Coliseum Friday and Saturday, Henderson said he has lifelong friends and business partners from that time.

He will have a special reason to smile during "1989 World Champion" and "Hall of Fame" autograph sessions with Jose Canseco, Carney Lansford, Dave Parker, Dennis Eckersley, Rickey Henderson, Tony La Russa and others. All proceeds from the sold-out autograph sessions and a private reception benefit the Angelman Syndrome Foundation (ASF).

"I think it just morphed into it," Henderson said, about how the club selected the cause he supports. "The A's always do community care. I've been getting the word out, so the whole trick of this is getting the right diagnosis and getting the voice out there."

Henderson said the ASF has invested more than $6 million in research, fellowships and symposiums aimed at improving therapies and finding a cure for the disorder that occurs in 1 in every 15,000 births. He leaves research strides to the scientists and said, "My job is to round up my buddies. I'm on the side of raising money."

Active in his son's care, when he's not working as a broadcaster or running his Oakland Athletics/Seattle Mariners Fantasy Camp, Henderson said raising a child with AS has made him a better human being. "I'm more aware of how good I have it. Listen, for me, (bad) traffic or going 0-for-4 in a baseball game, is not important. Today, we went to the beach and watched volleyball games. Coming home, we smiled. Every day, we smile. It's good."

Asked if the Seattle resident is an A's or a Mariners fan, Henderson dodged, saying, "I'm a baseball fan. I'm still a guy who loves hitters and hates pitchers. Every pitcher's arm should fall off, that's what I've always said."

But don't mistake his bluster. He still signs every autograph the same way he played ball: "Hendu, still having fun."