A Novel Mutation of Fanconi-Bickel Syndrome: A Case Report

A 19-year-old girl from a consanguineous marriage showed signs of delayed motor developmental milestones since infancy, a protuberant abdomen, and failure to thrive. She suffered from cor pulmonale as a result of restrictive lung disease, pulmonary hypertension, and chronic interstitial lung disease. Diagnosed with resistant rickets elsewhere, she was on treatment with Joulie's solution. Physical examination revealed an undernourished state and features of rickets. Laboratory results were suggestive of proximal renal tubular acidosis (RTA), dyslipidemia, postprandial hyperglycemia, and elevated alkaline phosphatase. Skeletal X-rays confirmed rickets, and an abdominal ultrasound showed hepatomegaly. Whole-exome sequencing identified a homozygous missense variant in the SLC2A2 gene (p.Glu486Gly), confirming Fanconi-Bickel syndrome (FBS). Management included phosphorus, bicarbonate, vitamin D supplementation, dietary changes, and conservative care. Follow-up showed improvement in height. Fanconi and Bickel (1949) initially reported the rare disorder known as FBS, which is attributed to mutations in the glucose transporter 2 (GLUT2) transporter gene. Due to its autosomal recessive inheritance, genetic counseling and prenatal diagnosis are essential. To the best of our knowledge, this is the first reported case in the world of a novel genetic mutation causing FBS.