When Jeffrey Chai-Seong visited the Charlotte immigration office last month, he left empty-handed.

On Thursday, he left as an American citizen.

The autistic 19-year-old originally from Canada was denied citizenship by immigration officials in June because he could not speak the oath.

His parents and two older brothers became citizens that day, but their frustration over Jeffrey's situation led his mother and father to contact U.S. Sen. John Edwards, who wrote a letter to federal immigration officials asking them to look into Jeffrey's case.

Earlier this week, the family, which lives in Cary, was notified that Jeffrey would be invited back for a private citizenship ceremony.

A 2000 law permits people who cannot speak to be given a waiver that would enable them to become citizens. But three years passed, and immigration officials hadn't come up with any regulations to apply the law.

On June 30, sparked by Jeffrey's story, immigration authorities created guidelines for people unable to speak due to a medical disability. Instead of a verbal swearing-in ceremony, disabled people can become citizens if they present a letter from a doctor attesting to the disability and are accompanied by a parent or legal guardian.

There are six cases like Jeffrey's in the Charlotte Bureau of Citizenship and Immigration Services, said Richard Gottlieb, officer in charge of the Charlotte office. Gottlieb said his office will let the other families know about the new regulations and make arrangements to have them become citizens.

On Thursday, Jeffrey Chai-Seong sat peacefully in Gottlieb's office as his mother, Beverly, signed his naturalization certificate. His father, Peter, snapped photos.

"I'm very glad his case cleared the way for other cases," said Peter Chai-Seong. "He's part of our American family now."