A WOMAN from Bala recently became one of 17 people taking part in a campaign to highlight rare diseases. Mel Williams is Mel is one of the changemakers for the I am number 17 campaign, aiming to raise awareness of many challenges the rare disease community face and highlight the fact that 1 in 17 people will be affected by a rare disease at some point in their lives. Mel only received her diagnosis of Hypophosphatasia (HPP) at the age of 52, despite living with the condition her whole life. HPP is an inherited metabolic bone disease that results from low levels of an enzyme called alkaline phosphatase (ALP).