32 seconds. That’s how much time Brady could tolerate exposure to light on his skin before the onset of deep burning, itching pain. Brady is living with erythropoietic protoporphyria, EPP, a rare inherited disorder that causes the skin to become painful when exposed to sunlight. Seconds, minutes, or hours beyond 32 seconds, for Brady, could result in intense, prolonged pain, which would require hours or days in darkness to recover. Kristen, Brady’s mother, shares with David Rintell, Head of Patient Advocacy at BridgeBio, how Brady was diagnosed, and how he manages the effects of the condition. EPP affects every aspect of Brady’s life, forcing him to calculate his cumulative exposure to sunlight while outdoors, through windows, or from reflections. Now 18-years-old, Brady has creatively learned how to navigate the condition through protective clothing and jumping from shadow to shadow. Morgan Paull, Head of Strategy at Portal, a BridgeBio program working on EPP, provides a medical overview of the condition. He explains that EPP is caused by the deficiency of an enzyme called ferrochelatase. When there is not enough ferrochelatase, the body is unable to convert the compound protoporphyrin into heme, a molecule that enables blood to carry oxygen. As a result, protoporphyrin builds up in the blood, skin, and liver. Sunlight exposure activates the protoporphyrin, generating a reaction that leads to inflammation and severe pain. Accumulated protoporphyrin can also cause liver damage leading to liver disease.