Late diagnosis of a rare urea cycle disorder mimicking kleine-levin syndrome

Abstract

Kleine-Levin syndrome (KLS) is a rare disorder characterized by recurrent episodic hypersomnia, cognitive changes, and neuropsychiatric symptoms between months of interictal normality (table). Triggers include infection, sleep deprivation, or alcohol intake, and diagnosis requires exclusion of other medical etiologies. 1 Urea cycle disorders are most commonly diagnosed via newborn screening or during workup of early, life-threatening hyperammonemia. We describe a young man with a late-onset urea cycle disorder who initially presented with phenomenology akin to KLS.