Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, epsilon polypeptide (YWHAE), on chromosome 17p13.3, has been shown to play a crucial role in neuronal development. The deletion of YWHAE, but not platelet-activating factor acetylhydrolase, isoform 1b, subunit 1 (PAFAH1B1), underlies a newly recognized neurodevelopmental disorder, characterized by significant growth retardation, developmental delay/intellectual disability (DD/ID), distinctive facial appearance, and brain abnormalities. Here, we report on a girl with a terminal deletion of 17p13.3, including YWHAE but not PAFAH1B1, showing normal brain structure on MRI. She had mild developmental delay, a distinctive facial appearance, and severe growth retardation despite normal growth hormone levels, which was improved by growth hormone therapy. Expression analysis of YWHAE and PAFAH1B1 yielded results consistent with array CGH and FISH results. These results indicate that the dosage effect of YWHAE varies from severe to very mild structural brain abnormalities, and suggest that the expression of YWHAE is associated with a complex mechanism of neuronal development. © 2012 Wiley Periodicals, Inc.