ALTADENA ( —  Police in Altadena are hoping the public can help them track down a missing 19-year-old.

Jonathan Taylor Clark was last seen about 2:20 a.m. Saturday in the 100 block of West Loma Alta Drive.

The missing man’s family says Clark has autism.

He reportedly took some money and his identification from his mother’s purse and left the residence on foot.

Clark takes medication several times a day. His mother says without his medication, he reverts to an approximately 7-year-old boy. His family says he has run away from facilities and his home previously and because he has been known to make poor decisions, police call him “at risk.”

Deputies from Altadena station began a grid search, advising other local sheriff’s stations and police department’s, as well as activating the Altadena and Montrose Search and Rescue teams to aid in the search.

Anyone who may have seen Clark is asked to contact the Sheriff’s Homicide Bureau at (323) 890-5500.