One patient with syndromic features harbored a heterozygous 17q12 microdeletion encompassing HNF1B, approximately 1.5 Mb in size, and presented with global developmental delay, intellectual disability, epilepsy, dysmorphic facial features, persistent hypomagnesemia, and a bicornuate uterus with normal renal structure. The gene discussed is HNF1B; the disease is Global developmental delay.