At the age of 21, I discovered I had a great aunt that I didn't know existed. My maternal grandmother, who was one of five, had a sister who had whooping cough as a child and was brain-damaged as a result. She led a fairly independent life in sheltered accommodation but was never introduced to the rest of the family. I was only told about her because she was going to be at the funeral of their other sister. I kind of understood why my gran never told me about her (she is of "that" generation) but was amazed that my mum had never said anything to me.