HIP1 and Williams syndrome: Distal microdeletions of chromosome 7q11.23 have been associated with some or all of: epilepsy, intellectual disability, learning difficulties and neurobehavioral abnormalities.1 These microdeletions are adjacent to the common Williams-Beuren syndrome deletion region on chromosome 7q11.23.2 The two genes commonly deleted are HIP1 (OMIM 601767) and YWHAG (OMIM 605356), encoding huntingtin-interacting protein 1 and tyrosine monooxygenase-3/tryptophan 5-monooxygenase activation protein, gamma isoform, respectively.1