Heterozygous activating mutations of KCNJ11 (Kir6.2) are the most common cause 
of permanent neonatal diabetes mellitus (NDM), and successful glycemic control 
has been obtained in several cases with oral sulfonylureas (SU). We have 
verified a lack of clinical response for both glycemic control and neurological 
features in an infant with permanent neonatal diabetes mellitus and DEND 
syndrome due to a V59A mutation in the KCNJ11 gene. Thus, our case reinforces 
that most cases with DEND syndrome are insensitive to SU.