William Szoradi shows no obvious signs of Marfan syndrome.

Yet if the three-year-old had not been diagnosed, his parents could have discovered his condition in the worst way possible.

Marfan syndrome, which is found in one out of approximately 3,000 people, affects the connective tissue between our limbs and organs.

The disorder can cause dislocating limbs and vision defects where the lenses of the eyes fall out of position.

People with the condition may also exhibit ‘stretched’ limbs, fingers and toes – but some show no obvious signs.

If unnoticed, however, Marfan syndrome can cause the lungs to collapse and the aorta – the main artery of the heart – to burst causing almost instant death.

READ MORE: This woman's amazing weight loss has given her new hopes of having a baby

Thankfully, William’s condition is closely monitored after he was diagnosed in March.

His parents, Claire and Tim, had noticed he was struggling to see things.

But it was only during a trip to the optician when the family realised his impaired vision was part of a wider problem.

Claire, 31, of Meltham, said: “I had never heard of it before and thought he didn’t look like someone with it.

“It was absolutely terrifying when I read about it.

The Szoradi family of Meltham, Tim and Claire with William (centre) who suffers with Marfan syndrome with his brothers Alex (back) Alfie (right) and sister Brooke.

“But I feel better now I do know and with all the monitoring they will pick up on the symptoms before it’s too late.”

William enjoys playing like a normal toddler but Tim and Claire must keep a close eye on William – and contact sports will be off-limits.

Claire said: “If it isn’t diagnosed someone could be playing football, their aorta could burst, an aneurysm could form and they’d drop down dead...

“It’s finding a balance between letting him lead a normal life and watching him closely.”

It is suspected that dad Tim may also have the condition; he has long limbs and suffered a collapsed lung some time ago.

And if Tim is diagnosed with Marfan syndrome, the pair’s other three children, Brooke, Alex and Alfie, will have to be tested.

READ MORE: Two schools forced to close after Huddersfield mains burst

To raise awareness of the condition – and cash for the Marfan Trust – the family are holding a fun day at Jackson Bridge WMC on June 12 (2pm).

The event includes live music, a bouncy castle and children’s entertainers.

Claire said: “We really want to raise awareness rather than anything else – even GPs don’t know that much about it.

“The leaflet we got about Marfan syndrome from Leeds General Infirmary was printed in 1981 – that was quite upsetting. It makes you feel a bit like you’re on your own.

“Even if people don’t fit the bill, go to the GP and get tested because you don’t want to find out in the worst possible way.”

For more information about Marfan syndrome visit: www.marfantrust.org .