HIP1 and neurodevelopmental disorder: In a study including 26 individuals from ten unrelated families with distal 7q11.23 heterozygous deletions of variable size (ranging from ∼4 Mb to ∼180 kb) including HIP1, Ramocki et al reported that probands exhibited an incomplete penetrance of epilepsy (80% of probands), neurodevelopmental disorders (58%), and learning disabilities alone (17%).1 For example, some individuals in the families with distal 7q11.23 deletions had normal cognition despite presenting with epilepsy.