While preparing for the 2014 run, Ms Andretta became sick and was diagnosed with type 1 diabetes, the same auto-immune condition her grandfather had managed his whole life.
Now, one year later, Carla is determined to run in the 2015 event, which falls on her 30th birthday this Sunday.
�It is good because my friends and family can see this part of my life, which I haven�t really talked about to anyone,� she said.
She said she appreciated the support she had so far received, especially from her seven-year-old son Maurice.
�My precious son said he would run with me,� she said.
�He has been my little hero � he is always very caring and understanding about my diabetes.�
Ms Andretta has always enjoyed running, but dealing with hypoglycaemia (low blood glucose) caused by her type 1 diabetes has now made it very difficult.
�Running was a big part of my life before my diagnosis, but now that freedom is gone,� she said.
She relies on multiple insulin injections each day, but said care plans for diabetes had come a long way since her grandfather�s day.
She said she hoped she could help improve the lives of people with diabetes by fundraising.
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