Seizures and diagnostic difficulties in hyperinsulinism- hyperammonemia syndrome

Abstract

Hyperinsulinism/hyperammonemia (HI/HA) syndrome is a rare disorderpresented with recurrent hypoglycemia and elevated serum ammonia, whichmay lead to development delays, permanent neurologic damages, if it remainsunderdiagnosed. It is caused by activating mutations in the GLUD1 gene whichencodes the intra-mitochondrial enzyme glutamate dehydrogenase (GDH).HI/HA syndrome is considered the second most common form ofhyperinsulinism (HI), and usually associated with epileptic seizures, mentalretardation and generalized dystonia.We reported a patient who was diagnosed as HI/HA with multiple episodesof seizures; and previously had been diagnosed and treated for epilepsy. Shehas heterozygous mutation in GLUD1 gene. Treatment with diazoxide enabledcomplete resolution of the seizures.One year later, when her brother was six months old, he was also diagnosedwith HI/HA. Later, the same mutation of GLUD1 was detected in both herfather and brother too.