Sammy Milewski, 29, had son Greyson James after a one-night stand with Coronation Street star Jack Shepherd, 26, in 2010 – behind the back of Lauren Shippey, now his fiancée.
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The 3-year-old suffers from the incurable one-in-a-million genetic disorder called alternating hemiplegia, which causes temporary paralysis, epilepsy, dystonia, learning disability and neurological abnormalities, poor motor organisational skills and intense pain.
Absent dad Jack quit Twitter on Monday – the day after news of Greyson’s disorder broke.
And now Sammy has alleged that Jack, who has a son and a daughter with Lauren, 25, has never met Greyson – but has known for two years he is battling illness.
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She said to The Sunday People: “Nobody knows what the future holds for any child, disabled or not.
"Anything could happen and one day he might regret not meeting him. But only one person can answer that."
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However, despite being overwhelmed by the "terrifying and heartbreaking" battle her son faces each day, Sammy has insisted she does not want to criticise his famous father.
She said: “I don’t want to criticise the baby’s father because Greyson and I do fine. I’m speaking out to raise awareness of alternating hemiplegia.
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