Consultants to financial advisers constantly preach about weeding out nonprofitable clients and focusing on the wealthiest prospects and largest accounts.

But Mike Byrne, a partner at Lighthouse Planning Consultants LLC, in Cherry Hill, N.J., thinks differently. About 30% of his clients are not profitable — and he plans to keep it that way.

Byrne specializes in serving families with special-needs children. Those families are frequently overwhelmed and rarely wealthy.

"It's a storm, and there's nobody out there helping these people," said Byrne, who is a notable exception. Families with special-needs children are a challenge for the adviser.

"It's a break-even to a loss — mostly a loss," he said, describing a category that makes up nearly one-third of his book of business. "But we have $300 million of assets under management, which means we have lots of revenues from the other parts of the practice that subsidize the special-needs area."

Byrne's commitment to serving this often-ignored part of the market springs from his personal experiences.

Both his older brother and younger brother are mentally retarded because of a genetic disorder known as Phenylketonuria and commonly referred to as PKU.

"Babies are now tested for it right after they're born, and when it's diagnosed, it's totally preventable," he said.

Byrne started to learn about the complexities of financial planning and estate planning for families with special-needs children as he helped his parents navigate through the process.

Later on, Byrne would learn that his daughter has a form of mental retardation, one that differs from that of his brothers. After her birth 20 years ago, Byrne discovered — this time as a parent — the challenges of having a special-needs child.

"I was realizing how dysfunctional everything is as far as getting information," he said. "When my daughter was about 8 or 10, I made a concerted effort to learn everything I could about special needs so that I can be a resource to parents out there."

A business partner might be hesitant to support a model like Byrne's, but Lighthouse Planning is organized in such a way that it's a nonissue, he said.

Byrne and his partner, Marc Neumann, combined their independent planning practices five years ago largely to share expenses and overhead costs. But they divide their revenue according to how much each generates.

"What we hunt, we keep, in terms of revenue," Byrne said.

That sort of model is common when partners with individual, prior books of business come together and the partner with a bigger book wants to be protected, said Zachary Gronich, the chief executive of RIA in a Box, a New York consulting firm. "Plus, it keeps both partners honest and hungry."

Byrne said there are two categories of special-needs families. One is so overwhelmed that they avoid financial planning. "They close their eyes and hope it will all work out," he said.

Another type is so focused on helping the special-needs child that they neglect the other children.

Byrne does financial plans for special-needs clients, often waiving the fee. He helps to guide them through the tangle of federal and state rules and systems pertaining to education and housing.

And he provides specialized estate planning advice. A frequent message Byrne conveys to clients is that assets must be passed on through a special-needs trust; if they are not, the government benefits of the special-needs recipients may be put at risk.

Byrne reminds families not to overlook the needs of their special-needs children's siblings — advising them, for instance, to set up and fund section 529 tuition plans.

Many families "don't understand that life is also challenging for the child without special needs," he said.

Byrne's clients don't always have young children. A large number of adult special-needs individuals live with their aging parents; because of budget cuts, there is far too little housing, he said.

Certain insurance companies have in-house credentials for serving special-needs clients. But Byrne bemoans the absence of an industrywide designation.

Any adviser or broker can call him or herself a special-needs planner. They often push products such as second-to-die insurance policies that are inappropriate for certain families, Byrne said. "You need a more holistic view," he said.