William Reinecke’s young daughter simply knew which shoe to put on which foot, but his son, who has autism, needed help to learn that skill.

John Reinecke, 10, now has a piece of masking tape inside his left shoes. He knows that his left foot is always the first foot on which he will place a shoe. And he puts that foot into the shoe with the masking tape.

John works with a therapist for about three hours every day after school learning things other children might take for granted, such as how close to people he should stand and how to stick to one topic of conversation for the appropriate amount of time.

He’s been working with his therapist, Shannon Doughty, owner of Carolina Coast Behavioral Services, for about four years. Doughty said it’s important for children who have autism to be identified as early as possible and to begin receiving behavioral services. Those who get help when they are younger tend to fare better in life.

The Medical University of South Carolina will help gauge the prevalence of autism spectrum disorders with the help of a $1 million grant from Autism Speaks.

Once the prevalence of the disorder is better understood, services can be better targeted to children who need them, said Laura Carpenter, one of the principal investigators on the study. Carpenter said the study is important because there has been a dramatic increase in the number of children diagnosed with autism in recent years.

All parents of children born in 2004 who attend public schools in Charleston, Berkeley and Dorchester counties, and some private school parents, will be asked to complete questionnaires over the next two years on their child’s social development, Carpenter said.

The three-year study — called the South Carolina Children’s Educational Surveillance Study, or SUCCESS — will conduct broad screening and targeted diagnostic assessment to better understand typical development in 8-year-old children as well as estimate the prevalence of autism spectrum disorders among children in Charleston, Berkeley and Dorchester counties. The large-scale study of about 8,500 children is the first of its kind, Carpenter said.

It will attempt to determine if children are being over-diagnosed, that is if kids who simply are quirky are being diagnosed with autism spectrum disorders, or if perhaps too few children have been properly diagnosed.

The information parents provide will be kept confidential, she said. And about 10 percent of them will be invited to bring in their child for an in-person assessment. It’s important that all parents complete the questionnaire, she said, even if their children already have been diagnosed with autism or have no symptoms of the disorder.

William Reinecke knows how important it is to gather such information, he said. Getting the right services for children with autism is “wildly important,” he said. “It makes all the difference in the world.”

Reach Diane Knich at 937-5491 or on Twitter @dianeknich.