Update April 29, 8:58 p.m.: It turns out Billy Joel has seen Ethan Walmark’s “Piano Man” performance, which went viral over the weekend, and the recording artist is impressed. Joel issued the following statement through a spokesperson Sunday:

“I think I like his intro to “Piano Man” better than mine. And this kid plays with a lot more energy than me. Maybe he could teach me a few things.”

Walmark’s parents issued the following statement Sunday evening in reaction to their son’s performance going viral and Joel’s statement earlier Sunday afternoon:

“The past 72 hours has been like living a Fellini movie! We are honored and humbled that Mr. Joel watched Ethan’s video, and took the time to make such gracious comments about his piano playing. If Ethan’s love and joy of music can change one person’s mind about autism, we are happy.”

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Original post: It’s not every day that you get to watch a 6-year-old play Billy Joel’s “Piano Man.” But thanks to YouTube, you can watch Ethan Walmark play it and other hits over and over again.

Walmark, who has autism spectrum disorder, has a series of videos on YouTube in which he’s shown playing classic songs, including “Maybe I’m Amazed,” “Dear Prudence” and, in a duet with his sister, “Mockingbird.”

The National Institutes of Health defines autism as “a complex developmental disability that causes problems with social interaction and communication.” Symptoms generally start before the age of 3.

The videos of Ethan are stunning, given his age, and provide a window into the complex nature of the disorder, which manifests itself in a variety of ways, mainly affecting communication and social behaviors. Ethan’s parents, Michael and Allison Walmark, have a donation page on the “Walk Now for Autism Speaks” Web site. They are listed as team captains of “The E-Team,” and are ranked second, with more than $25,000 raised of the $100,000 fundraising goal.

As The Post’s Janice D’Arcy reported in January, autism “is a word that haunts parents,” with more than 36,000 children in the United States receiving the diagnosis each year.

The American Psychiatric Association is compiling the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM). The manual is widely regarded as the authoritative guide to the classification and diagnosis of mental disorders. The edition could feature new diagnostic criteria for autism spectrum disorder, potentially affecting parents who rely on services made available to children in whom the disorder is diagnosed under existing guidelines. The new DSM is under review and is expected to be published in May 2013.

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