PAX6 and obesity due to melanocortin 4 receptor deficiency: In addition, aniridia is associated with several non-ocular conditions such as obesity, glucose intolerance and diabetes, and anosmia.3, 4 These conditions are due to a requirement for PAX6 expression for the development and maintenance of the brain, pancreas, and gut.5, 6, 7 The progressive nature of the disease reflects an ongoing requirement for PAX6 expression and suggests there may be an opportunity for therapeutic intervention postnatally.