When she was 17, Fanny Chung's hands started to shake uncontrollably, but her doctor told her it could not be Parkinson's disease. 'You're so young,' she recalled him saying.
It was not until she was 28 that she was diagnosed with the genetic form of the disease - when it was discovered in her sister, who was then 39.
Now 49 and 60, they have lived with the condition, autosomal recessive juvenile Parkinson's disease, for most of their lives, suffering from periodic episodes of shaking and difficulty controlling their movements - suddenly falling over or dropping things.
Theirs are two of five cases in Hong Kong in which the patients are believed to have inherited a defective parkin gene from their parents.
'The doctor told me I would have to take medicine for the rest of my life, and that from time to time there will be episodes,' said the elder sister, May. 'People look at me as if they were thinking, 'Why are they walking so weird'?'
She has since found that her three daughters are recessive carriers. She now wants to test her grandson, even though doctors say it is unlikely he will develop the genetic disease.