Dai et al. [26] also sought to delineate the role of these transcription factors in the WS phenotype, finding that an individual with an atypical deletion that included GTF2IRD1, but not GTF2I, presented with poor performance on a number of spatial subtests from the Wechsler Preschool and Primary Scale of Intelligence- Revised (WPPSI-R) [27], including ‘Block Design’, ‘Object Assembly’, and ‘Mazes’. Here, GTF2IRD1 is linked to Werner syndrome.