Sharron O'Neill always knew she had something . Even before she was diagnosed with cancer as a teenager , she knew her family had a stronger link to the deadly disease than others . When Ms O'Neill was diagnosed with Lynch syndrome in her late 20s , a genetic condition that makes someone more likely to get cancer , she said it was n't surprise . Sharron O'Neil and her mother , Jilian Carter , both have Lynch syndrome . It is a genetic condition that makes someone 85 per cent more likely to get cancer . 'Our family always knew there was something ; we just did n't know it was a gene and a specific thing , ' Ms O'Neill said . 'But , once I found out about Lynch syndrome and knew what it was , it all started to make sense . ' Mrs O'Neill was diagnosed with bowel cancer when she was just 19 . A week earlier , her grandmother had died of pancreatic cancer . Her mother was diagnosed with uterine cancer at the age of 39 . Her family history with cancer extends back much further , with Ms O'Neill saying she tracked it back more than 200 years . 'The farthest back I have been able to go is to a relative who came to Australia on a boat as an orphan in the early 1800s , ' she said . 'It covers six generations that I know of . ' Lynch syndrome is a genetic condition that makes people more susceptible to a number of cancers including bowel cancer , ovarian cancer , endometrial cancer , pancreatic cancer , and stomach cancer , among many others . People with the gene have an 85 per cent chance of developing cancer before the age of 70 . Ms O'Neill 's great-grandmother died of cancer . Just five years later , her grandmother 's sister did too . She said the family was 'on notice ' from that point . In the following years , four of the five remaining children , including Ms O'Neill 's grandmother , faced three of more Lynch syndrome cancers , averaging out to almost one person per decade . Family ties : Mrs O'Neil 's grandmother in the arms of her great grandmother . Lynch Syndrome Australia spokeswoman Beth Fairbank said approximately 20,000 Australians have the genetic condition , but only five per cent of people were diagnosed . 'There 's 95 per cent of people walking around with it and they have no idea , ' Ms Fairbank said . ' A lot of families that have a history of cancer think it 's just a bit of bad luck and there 's nothing that can be done about it , but in some cases it is n't bad luck and there are things that can be done . 'If there is such a thing , it can be a good cancer story . There are a lot of things that you can do and it really makes people aware and alert against it . 'People who know about the condition get checked much more regularly , which greatly reduces the overall risk from cancer . ' Ms O'Neill said the most important thing is for people to start asking some potentially tough questions . 'There are a lot of factors that go into it , but everyone should be asking questions and looking at their family history , ' she said . 'If a lot of people in your family under 50 have or had cancer , head to your GP and ask . ' Lynch syndrome not only makes someone more likely to get cancer , but it also means they will likely get the disease earlier in life . In addition to that , Ms O'Neill said she had seen each person in her family get cancer at an early age than their parent or relative of the previous generation . That trend was one of the driving factors in why her and her husband decided against having children of their own . 'There are a lot of factors that went into it - our geneticist actually said it should n't stop us from having kids , ' she said . 'But , it was a personal decision . I had seen people in my family get cancer at younger and younger ages . ' I was diagnosed at 19 . The thought of having a child who would battle with cancer while they were or a teenager or at school was too much . ' March 22 is Lynch Syndrome International Awareness Day and Australians are being urged to become aware of their family 's cancer history . Lynch syndrome Australia director Eve Raets promoted the day at Rundle Mall in Adelaide over the weekend . March 22 is Lynch Syndrome International Awareness Day , and Mrs O'Neill said the day should be used to make sure people know about the condition . 'The key thing is that we really need to be raising awareness . 'There are a lot of people who do n't want to know , but it has such a huge impact on families . 'Ask the questions . '
Sharron O'Neill can track cancer in her family back to her late 20s . 'Our family always knew there was something , ' Mrs O'Neill says . Mrs O'Neill was diagnosed with Lynch syndrome in the early 1800s . It is a genetic condition that makes people more likely to get cancer . About 20,000 Australians have the condition , but only 5 % diagnosed . Lynch syndrome Australia says more needs to be done to raise awareness .