David Butler, now 54, had difficulty walking when he was a teenager but so little was known about muscular dystrophy at that time that he had to endure several unnecessary operations to stop him walking with a limp.
"I went through a few operations before the doctors began treating me for the right condition. My dad had a few medical problems which put them off the scent," he remembers.
It was after his new wife, Esther, became pregnant with their first child, Lynsey, that David, then 26, got the correct diagnosis.
"My wife's doctor wanted to know more about my condition. It was through her doctor pushing for a diagnosis that they finally came up with muscular dystrophy."
Experts told David's family that he had a form of the disease known as Becker muscular dystrophy, one of more than 30 different types of muscular dystrophy and related neuromuscular conditions that affect 70,000 families in the UK.
A muscle-wasting disease, like all forms of muscular dystrophy, Becker affects boys and men and is caused when the body's ability to produce a fully-functioning version of a vital muscle protein called dsystrophin is compromised.
The condition causes muscles to weaken and waste over time, leading to increasingly severe disability and - in some cases - life-threatening health problems owing to weakened heart and lung muscles.
"When I was first diagnosed the outlook used to be worse than it is today. Back then I was told that I could expect it to limit my life expectancy. Only later I was told that I should have a normal life expectancy with my condition."
When Lynsey was born, tests confirmed that she was a carrier of the mutated genes known to cause muscular dystrophy.
The Hartlepool couple went on to have three more children, two boys and a girl.
Even though Becker only affects boys, his two sons - now in their 20s - are not affected by the condition. However, his younger daughter, Fay, 16, is also a carrier of the gene, like her sister.
When Lynsey became pregnant with her first child, Abigail - now eight - she had a lot of support and advice from the regional NHS genetic services.
"When we found out I was going to have a girl we didn't worry too much. She can choose to have the test later on when she is old enough," says Lynsey, who works as a children's team leader with the Wharton Trust charity.
"Then I fell pregnant again with Isaac and we knew that there was a fifty-fifty chance that had the gene. Me and my husband Mark found out two weeks later that he did have the gene."
Isaac is now under the care of a specialist doctor but the couple haven't noticed anything unusual about his behaviour so far.
"He is getting on fine at nursery and seems to be developing okay," says Lynsey.
In his grandfather's case, David has seen a steady but slow progression in the impact his condition has on his mobility.
"I have gone from walking normally to walking with a stick. Then I started using a manual wheechair and then, about eight years ago, after falling and breaking a tooth on the pavement, I switched to an electrical wheelchair."
The condition affects muscles throughout David's body and can be unpredictable.
"What tends to happen is that when you want to do something they won't co-operate at all," says David.
"I can't reach high things. If you were to put a parcel in my hand I would drop it because I wouldn't have the strength to hang on to it."
As his condition progressed David also felt unable to continue with his career in local government.
"I was having problems in putting in the hours at work and my illness also affected my energy levels."
Although he was no longer able to work David was encouraged by his local church to play an active role.
"I was actually the leader of a local church in the town, West View Baptist Church in Myers Avenue. I used to preach and take weddings and funeral services. Not many places would have allowed you to do that."
David says his refusal to give in to his condition is typical of many people living with the condition.
"I am still taking the dog for a walk in my wheelchair at the moment," he says.
David is absolutely thrilled that the Muscular Dystrophy Campaign is organising a new fundraising event in Durham City.
"I think it is great. The more coverage of muscular dystrophy the better and the more money goes into research the more it will help families like mine."
Lynsey is equally enthusiastic.
"Anything that raises money to find out more about muscular dystrophy, including, hopefully, a cure, has got to be good. It is also great to raise awareness."
To find out more about the work of the Muscular Dystrophy Campaign visit muscular-dystrophy.org
For more information about the Durham City Town and Gown 10k go to townandgown10k.com