I recently had a birthday. As usual, I received a handmade card from Beth Catlin, who has been sending me such birthday greetings for more than three decades, even though we’d never met until 2009.

That was the year I decided it was time to finally meet Beth in person, so I visited her workplace, the C. Wilson Pollock Industrial Training Center.

“Hi, Beth,” I said, shaking her hand hello. “I’m Ronnie. It’s wonderful to finally meet you. Thank you for all the cards.”

She looked at me with brief intensity, then her eyes darted away as she said: “Ronnie. July 3.” Which is my birthday.

I mentioned the names of several of my many siblings, to whom she also sent annual greetings, and she recited their birthdays, too.

“That’s right,” I said. “You’ve got them all correct.” She smiled, pleased, and said, “Yeah.”

Beth, now 59, is an autistic savant. Intellectually and developmentally disabled, she lives on a sweet little block with her widowed mother, Barb, who is now 88. Her dad, Don, passed away suddenly seven months after my visit.

But he was alive and vivacious the day we met, eager to talk about the extraordinary mission Beth began some time in 1972: She sends handmade birthday greetings to every person she has ever met — and to their friends and relatives, whether she has met them or not. Beth’s sister went to school with my sister; Beth got my name and date of birth from her.

Astonishingly, each of our 5,000-plus names, addresses and birthdays are not listed in a personal address book but are instead permanently encoded in Beth’s brain. The spellings are exact, our birth dates precise. And not one card has ever been returned to her because of a wrong address, said her mother.

“This is her gift,” Barb explained to me back then while I watched, astonished, as Beth addressed — from memory — more than a dozen cards at the desk where she still keeps her notes, envelopes and stamps. “Hers is a world of word and number association and constant observation, mixed with interrogation.”

Physically, her gait is slightly unsteady, but it does not impede her daily walks around the neighborhood or from full-time employment at nearby Wilson Pollock, where she has worked for 38 years alongside other adults with disabilities doing assembly work for vendors.

While her gift is not uncommon among “number” savants such as herself, I find it immensely moving that it manifests itself in such a thoughtful way.

“Some people have told us that Beth’s card is the only birthday greeting they can rely on receiving — or the only one they look forward to opening,” said Don, who described his daughter as “one of the most extraordinary people I’ve ever known.”

In return, hundreds and hundreds of people in her “birthday circle,” as I like to call it, respond in kind, sending Beth cards on her own special day: Sept. 22. Barb said her daughter’s face glows with excitement when the mailbox overflows with so many birthday cards.

“Beth has made so many people happy with her thoughtfulness,” said Barb, as I hugged her goodbye that day, profoundly touched by the family’s pride in her. “This is our reward — and her triumph.”

Ronnie Polaneczky is editor of the Philadelphia Inquirer’s good news section, the UpSide.