Pallister-Hall syndrome is a rare autosomal dominant condition that is associated with polydactyly and hypothalamic hamartoma and is caused predominantly by frameshift or nonsense pathogenic variants in the GLI3 gene. The majority of cases are identified during childhood; however, rare reports of diagnoses during adulthood exist. Here, we describe the identification of a novel nonsense GLI3 pathogenic variant in an adult male following the incidental detection of a hypothalamic hamartoma.