Blocks of lego, toy dinosaurs, balloons and birthday cards.

North Norfolk News: Kaiden Griffin who has a congenital heart defect, plays as he celebrates his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEYKaiden Griffin who has a congenital heart defect, plays as he celebrates his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEY (Image: Copyright: Archant 2018)

Kaiden Griffin's living room is like that of any other little boy celebrating his fifth birthday.

But despite his cheeky smile and playful nature, Kaiden is no ordinary child.

Diagnosed with a congenital heart defect called hypoplastic right heart syndrome, his heart, lungs and veins are abnormal and his condition is terminal.

Kaiden's parents, 23-year-old Kyra Welch and Kieron Griffin, were told their son would be lucky to reach the age of four.

North Norfolk News: Kaiden Griffin who has a congenital heart defect, with his mum Kyra Welch, on his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEYKaiden Griffin who has a congenital heart defect, with his mum Kyra Welch, on his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEY (Image: Copyright: Archant 2018)

And experiencing his childhood milestones is something they'll never take for granted.

Miss Welch, from North Creake, near Fakenham, said: 'In May 2014 doctors said his condition was terminal.

'They said it may be years but not many and that was four years ago. He's just proved everyone wrong.

'It was things like I'd never take him to his first dentist appointment or take him to get his haircut - but he had his hair cut today.'

North Norfolk News: Kaiden Griffin who has a congenital heart defect, plays as he celebrates his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEYKaiden Griffin who has a congenital heart defect, plays as he celebrates his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEY (Image: Copyright: Archant 2018)

Kaiden's condition affects the blood flow to his lungs.

Miss Welch said: 'He just gets a lot more tired than the other children.

'It does really restrict him.'

Kaiden attends school three mornings a week, with a one-on-one carer in the class to support him.

North Norfolk News: Kaiden Griffin who has a congenital heart defect, with his mum Kyra Welch, on his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEYKaiden Griffin who has a congenital heart defect, with his mum Kyra Welch, on his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEY (Image: Copyright: Archant 2018)

And he's enjoyed celebrating his fifth birthday, with treats including a family barbecue, a trip to the zoo and a party with friends from his class at school.

But in other ways Kaiden's childhood has been unusual.

Miss Welch said: 'I had to go for so many scans before he was born and then have him in London.

'He had to have an operation and they had to make sure they had a bed ready in Great Ormond Street for him.

North Norfolk News: Kaiden Griffin who has a congenital heart defect, plays as he celebrates his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEYKaiden Griffin who has a congenital heart defect, plays as he celebrates his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEY (Image: Copyright: Archant 2018)

'He has a lot of appointments but it's hard because there's not a lot they can do.

'We go to King's Lynn Hospital and they check his heart and his weight, and sometimes scan him.'

She added: 'I do get a lot of people saying: 'I couldn't do it.'

'But before I fell pregnant I was the most un-maternal person but you just sort of get on with it.'

North Norfolk News: Kaiden Griffin who has a congenital heart defect, with his mum Kyra Welch, on his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEYKaiden Griffin who has a congenital heart defect, with his mum Kyra Welch, on his fifth birthday, after doctors thought he would only live for two years. Picture: DENISE BRADLEY (Image: Copyright: Archant 2018)

But Miss Welch is not planning to have another child.

She said: 'I know there's only a small chance that another child would have a similar condition but Kaiden needs all of my love and care.'

'Happy birthday my little ray of sunshine' - Norfolk mum's moving letter to her terminally ill son

Norfolk mother Kyra Welch writes about her experiences with her terminally ill son, Kaiden Griffin.

'Five years ago to the day I was in a hot sweaty room in a London hospital awaiting your arrival.

'Five years ago, at 11.09pm this tiny little screaming baby entered the world. And he breathed on his own.

'From that moment I knew, I knew that everyday for as long as you could fight, you would fight until the end of your time and that's exactly what you've done.

'In your five years of living you have become the best part of me. Every single day you have proved everyone wrong.

'You wake up everyday smiling and you go to bed every night having achieved something new.

'I have never seen such determination, love and strength in someone so small. Someone who defies the odds every day of his life.

'They told us a few years ago today you wouldn't be here, we would be lucky for you to survive past the age of 4. That your heart should have stopped beating by now. Today you turned five.

'I can't even begin to express the overwhelming feeling of just how proud I am of you every single day.

'You make me laugh, smile, and love, more than I ever thought was possible.

'Thank you for being the strength I needed and thank you for choosing me to be your mum.

'I really am the luckiest mum alive.

'Happy birthday my little ray of sunshine.'

Read more: Norfolk mum of terminally ill boy on why she has no plans to have another child