Because of a severe medical condition, Stephany Osuji's mother has been unable to be present for some of her daughter's touchstone high school moments. So Jodi Millerbernd, Stephany's big sister by arrangement rather than blood, has often stepped into the breach.

Millerbernd, a development director for a nonprofit group in Rochester, Minn., has attended Osuji's basketball games and helped her get ready for prom. She also watched Osuji graduate and helped move her into the University of St. Thomas, where Osuji is a junior on full scholarship.

"I never tried to replace her parent, but to provide some support for Stephany, who has overcome huge adversity," said Millerbernd. "She's such a positive and strong person that she's like a role model for me."

"Jodi's a big person in my life," said Osuji, a native of St. Cloud, Minn., who also likes to snowboard. "It's been five or six years [that they've been together] and it's hard to imagine life without her."

Young people like Osuji, 20, have opportunities for such mentoring and friendship through the Big Brothers Big Sisters program. The group, whose Twin Cities chapter is based in St. Paul, serves youngsters of all races, interests and socioeconomic backgrounds, pairing them with prescreened adults. There are more than 6,000 sibling pairs in the Twin Cities, many of whom continue lifelong relations after the formal program has ended, said Gloria Lewis, president and CEO of the local chapter.

"We enrich children through one-to-one friendship with caring adults," she said. "We help young people to emerge more confident, competent and caring."

Her organization will get some help on its mission this weekend when another group, the Links Inc., has its biennial gala at the Hyatt Regency in downtown Minneapolis.

The ball, to be hosted by Twin Cities actor, singer and composer T. Mychael Rambo, is put on by a group of high-achieving black women dedicated to service and philanthropy.

The Links have at least 12,000 members in more than 270 chapters worldwide. The group's local chapter includes judges, lawyers, and corporate and community leaders such as retired General Mills vice president Reatha Clark King, Minneapolis deputy city coordinator Jayne Baccus Khalifa and chapter co-founder Marion Jones Kennon, a pillar of Breck School.

"When we were younger, many of us wanted to save the world," said Michelle Miller, president of the Minneapolis-St. Paul chapter of the Links Inc. and a vice president at Medtronic. "Now we want to impact our corner and effect change -- each one reach one."

The gala's theme is the Harlem Renaissance, with a Cab Calloway-style revue, with Rambo going hi-de-ho.

"It's for an excellent cause," said Kimberly Price, an assistant general counsel at 3M Co. and co-chair of the Links gala.

"We can't help but have an excellent event working for such energizing causes," added co-chair Sharon Ryan, a community volunteer."

Osuji's big sister Millerbernd said that she has been the one blessed by having a little sister. "Stephany and I are technically not matched anymore because she has aged out of the program," she said. "But she is a part of my family now, since my daughter calls her auntie."

For her part, Osuji is grateful for all the help she has received over the years, and the lasting bonds she has made. "Jodi expanded my support system," she said. "She keeps me on track."

Rohan Preston • 612-673-4390