A neurodevelopmental disorder caused by variation in the KDM2B gene. This disorder is characterised by speech delay, developmental delay, learning difficulties, and/or intellectual disability. Patients often present behavioral abnormalities including including autism and attention deficit hyperactivity disorder. Other phenotypic features commonly reported include heart defects, unilateral kidney agenesis, ophthalmological anomalies, broad nasal tip, large ear lobes, and exaggerated Cupid’s bow.