# Presentation and Management of Acute Mania in Fanconi–Bickel Syndrome, A Metabolic Genetic Disorder

## TL;DR

This case report describes the first known instance of acute mania in a patient with Fanconi–Bickel syndrome, a rare metabolic disorder.

## Contribution

It introduces a novel psychiatric manifestation of Fanconi–Bickel syndrome and suggests a potential link to bipolar disorder pathophysiology.

## Key findings

- A patient with Fanconi–Bickel syndrome experienced acute mania, a previously unreported psychiatric manifestation.
- The case suggests possible functional changes in neural pathways involving the paraventricular thalamus due to decreased GLUT2 activity.
- This finding may contribute to understanding the pathophysiology of bipolar disorder.

## Abstract

Fanconi–Bickel syndrome (FBS) is a rare metabolic disorder caused by decreased glucose transporter 2 (GLUT2) function due to several known mutations in the SLC2A2 gene. As of 2020, 144 cases of FBS have been described in the literature. Metabolic and somatic sequelae include dysglycemia and accumulation of glycogen in the kidney and liver. However, there are no descriptions in the literature of possible neuropsychiatric manifestations of FBS. This case report is to our knowledge the first in this regard, describing a patient with FBS who was admitted to our psychiatric inpatient unit while experiencing acute mania. We conceptualize the case as a novel psychiatric presentation of acute mania in FBS, which may inform our understanding of bipolar disorder pathophysiology because of the hypothesized functional changes in neural pathways involving the paraventricular thalamus induced by decreased GLUT2 activity in FBS.