Robin Williams was given the wrong diagnosis and it was only discovered during his autopsy

The son of legendary actor and comedian Robin Williams once spoke out about how his father's misdiagnosis of Parkinson's disease was only discovered after he'd died.

Robin Williams was misdiagnosed with Parkinson's disease - a brain disorder that causes unintended or uncontrollable movement such as shaking, stiffness, and difficulty with balance and coordination - two years before his death.

The globally acclaimed actor tragically died by suicide in 2014 at the age of 63.

Yesterday would have been his 73rd birthday, and his son Zak posted a tribute thanking the acclaimed star for all the people who'd told him they were helped through tough times by Robin.

He wrote: "Dad, on what would be your 73rd birthday, I remember you for all the hope and joy you brought to the world.

"There’s not a week that goes by without someone sharing with me how you helped them through a dark time or a rough patch.

"I’m so grateful and proud to be your son. Love you forever."

Robin Williams with his son Zak. (Richard Corkery/NY Daily News Archive via Getty Images)

When Williams died a decade ago an autopsy revealed that he was suffering from undiagnosed Lewy body dementia (LBD), that was progressively causing Parkinson's-type symptoms.

According to Mayo Clinic, LBD is the second-most common type of dementia after Alzheimer's disease.

It explains: "Protein deposits called Lewy bodies develop in nerve cells in the brain. The protein deposits affect brain regions involved in thinking, memory and movement."

There is currently no known cure or treatment to slow down the aggressive neurological disease.

Back in 2021, Zak also spoke out about the neurological disease and his dad's medical misdiagnosis on Max Lugavere's The Genius Life podcas, claiming it left him 'very uncomfortable' and 'frustrated' during what would be his final years.

Zak remembered: "What he was going through didn't match one-to-one [with] many Parkinson's patients' experiences. So, I think that was hard for him.

The star is known for several iconic roles. (20th Century Studios)

"There was a focus issue that frustrated him, there were issues associated with how he felt, and also from a neurological perspective, he didn't feel great. He was very uncomfortable", he continued, adding that the incorrect medical information and medication may have 'exacerbated the situation'.

"They're also really hard on the mind and the body.

"The diagnosis was different than the disease so I think it could be a situation where you're taking stuff and experiencing purely the side effects of [the drug]."

He went on to talk about how the disease and misdiagnosis prevented his father's skill and ability to 'perform his craft', impacting his mental health.

"I don't want to say it was a short period. It felt a lot longer than it actually was because it was a period for him of intense searching and frustration.

"I couldn't help but feel beyond empathy. I couldn't help but feel frustrated for him.

"It can be really isolating even when you're with family and loved ones."

The actor's widow, Susan Schneider, wrote an essay called 'The terrorist inside my husband's brain' after his death for scientific journal, Neurology.

In it, she talked about how the condition 'had done so much damage to neurons and neurotransmitters that in effect, you could say he had chemical warfare in his brain'.

If you’ve been affected by any of these issues and want to speak to someone in confidence, please don’t suffer alone. Call Samaritans for free on their anonymous 24-hour phone line on 116 123