The first thing most parents have to watch their child go through is the heel prick test, often deemed as one of those common, bog-standard procedures.

But this was not the case for Kimberley and Craig Rudd.

Five days after the couple had their first baby, Max, at Medway Maritime Hospital on October 21 last year, a midwife took blood samples from their newborn.

She told Mr and Mrs Rudd, of Noreen Avenue, Minster, that if they had not heard anything by the end of that week, they could take it that all was well.

However, on Halloween, Mrs Rudd got a call from the Evelina London Children’s Hospital to say they had Max’s results.

“Straight away I thought ‘Oh my God’,” she said.

“Just the fact they were ringing me made me think something was wrong.”

The 25-year-old added: “The nurse told me the heel prick test had suggested Max had phenylketonuria, or PKU, and I was like ‘What the hell is that?’

“She then told us not to worry, but that me and Craig needed to take him to the Evelina the next day for further tests.”

PKU is a rare inherited condition that occurs only when both parents are carriers.

At the hospital, The Rudds, who married in June 2015, were met with a consultant who told them Max lacked the enzyme that breaks down the amino acid phenylalanine, also known as “phe”, which then builds up in the blood.

If left untreated, it can cause brain damage.

There is no cure for PKU and the only treatment is a life-long, strict diet that keeps the amount of “phe” in the blood, which is essential for normal growth, at a safe and consistent level.

Mrs Rudd, an invoicing processor at Queenborough-based Medichem, said: “When they told us Max had PKU it was horrible.

“We had never heard of it before and we didn’t know we were carriers; we were just so upset.

“It came as such a blow to us because my pregnancy was perfect and the labour was perfect – we didn’t expect anything to go wrong.

“The dietician at the Evelina recommended to keep Max on a strict diet forever, which means anything high in protein, such as meat, fish and eggs, needs to be avoided.

"His diet will consist mainly of vegetables and fruit.”

They have to take blood samples from Max once a week to send to the hospital for monitoring.

The 13-week-old baby also has to drink “phe-free” formula milk, as well as a measured amount of breast milk, as part of his diet.

Mrs Rudd said: “It is a bit scary for us, especially as first-time parents, but we have got our heads around it a bit more now.

“I imagine it will get harder as Max gets older when he isn’t able to eat the same foods as his friends, but his dieticians have said they will help us through each stage.

“We are just taking each day as it comes.”

Earlier this month, the couple decided to fundraise for NSPKU, a charity helping and supports those with PKU and their families.

“The dietician recommended to keep Max on a strict diet forever, which means anything high in protein, such as meat, fish and eggs, needs to be avoided... his diet will consist mainly of vegetables and fruit - Kimberley Rudd

Mr Rudd is doing the British Major Series race on March 25 – a 12km muddy obstacle course – and his wife has started a JustGiving page to raise money to go towards research and equipment.

She said: “I set a target of £200 and now I have over £800 – we’ve smashed it and I’m really pleased!

“I would like to say thanks to everyone who has donated. A special thanks to everyone at Medichem and TAM Beauty for their generous donations.

“I’d also like to say thank you to Max’s consultant, Dr Lemonde, and all the other staff at the Evelina London Children’s Hospital who have helped and supported us over the past few months.”

Mrs Rudd has now upped the target to £1,000 and is organising a charity walk/run for Sunday, July 30 at 10am.

It will start at the beach huts on The Leas, Minster, and finish at Sheerness sandpit. Entry £10 per person and £5 per dog.

To take part, call Mrs Rudd on 07919 890464 or, to donate online, go to bit.ly/2jFSvNP