Maci Winters is a big sister to brother Ashton – but you wouldn't know it to look at them.
Because even though six-year-old Maci is two years older than 'little' bruv, she's slightly smaller than him – due to a rare condition that affects just 1 in 100,000 babies.
Maci, from Pontefract, West Yorkshire, is just 3ft 3in tall, weighs just 2st - that's less than a two-year-old - and wears clothes with an 18-24 month label. (The average six-year-old girl is 4ft tall and weighs over 3st.)
She was born with a rare genetic condition called Russell-Silver Syndrome, a form of primordial dwarfism that affects 1 in 100,000 babies.
The body is smaller than it should be even before birth and those affected also find it difficult to gain weight.
But despite being smaller than her school friends, she's just like any other six-year-old.
Last week, her parents, Lena Appleton, 30 and John Winters, 31, watched her take to the stage in the school nativity.
Her mother said: "We were so proud, but it did make us realise how big the other children were compared to Maci.
"She was all smiles in the nativity and singing along to all the songs. She lit up the room and kept waving to us begging to have more pictures taken. To us, she's our little Christmas angel."
Lena added: "When Maci was born we knew something was wrong. I was terrified when she had to be induced at 36 weeks.
"She weighed just 3lb 5oz and the doctors didn't have a clue why she was so small. "I took her home, but she didn't gain any weight when I fed her - she was too weak to suckle properly. The doctors told us she was a small baby but she'd catch up eventually."
She and John spent the next three years visiting geneticists and dieticians, desperate to know why their little girl wasn't developing normally.
Then when she was three, she was diagnosed with Russell-Silver Syndrome.
Common physical traits of those affected include a small, triangular-shaped face and a head which grows to be disproportionate to the rest of the body.
Her mother said: "There are adults with Russell-Silver Syndrome who have led normal lives and had children of their own. We have to be positive for Maci's sake. When we look back at what she's achieved it's just incredible.
"We still worry about the impact Russell-Silver Syndrome will have on Maci's life - but she's so confident and cheeky. She does get upset when people mention her size but now she's old enough to tell them off which is quite funny."
But her younger brother Ashton is already standing up for his older sister. At 3ft 5in, he is already taller and their height difference makes playing games even more fun.
Lena said: "Maci does get confused and asks why Ashton is taller, but he's so protective of his sister and he'll always stick up for her.
"She usually wins at hide and seek because she can fit into a little cupboard in the bedroom where he can't find her."
Maci is being treated with growth hormones to give her a bit more height and has recently had hearing aids fitted. She also finds walking long distances difficult and has a special purple wheelchair to help her along.
More on Parentdish: My twin sister is a dwarf
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