Patients’ needs and preferences don’t always match the preconceived notions of laboratory and medical professionals. In this interview, Heidi Wallis, president of the Association for Creatine Deficiencies, shares her family’s diagnostic odyssey. She also provides insights about how the biomedical establishment could better serve families like hers. Ms. Wallis has two children with GAMT deficiency, an inherited disorder that prevents the body from producing creatine. Her children were diagnosed in very different ways, with very different consequences.