Niemann-Pick type C disease (NPCD) is a rare metabolic illness, with autosomal recessive inheritance. NPCD has a heterogeneous presentation, with non-specific psychiatric symptoms, mostly affective and psychotic features and also cognitive deficits.

We present the case reports of two brothers with an adolescent-adult onset and discuss the evolution of their neuropsychiatric manifestations.

The patients have now 35 and 31 years old and the youngest was the first to develop clinical manifestations of the disease. From 16 years old, he developed unspecified neurological impairment with gait imbalance. In the next years, the neurologic manifestations exacerbated, with dysarthria, ataxic gait, and his academic performance declined. With 24 years old, he presented acute psychosis, with unstructured delusion and auditory hallucinations. The acute psychotic symptomatology remitted with olanzapine but he revealed social withdrawal, apathy and progressive cognitive decline that persist until now. His brother, whose diagnosis was made in the course of the family genetic study, developed the first signs of the NPCD with 19 years old. He presented neuropsychiatric compromise, with impaired learning, social isolation and insomnia. They are receiving specific treatment with miglustat and symptomatic treatment for the psychiatric manifestations.

NPCD is a rare metabolic disease, with neuropsychiatric compromise. No general psychopathological profile has been associated to NPCD. Sometimes psychiatric symptoms dominate the initial clinical presentation, with neuro-visceral signs appearing later. An atypical psychiatric symptomatology should be extensively investigated in order to exclude organic causes, including metabolic diseases like NPCD.