Fanconi-Bickel syndrome: Report of life history and successful pregnancy in an affected patient

Fanconi-Bickel syndrome (FBS, OMIM #227810) is a rare autosomal recessive disorder of carbohydrate transport originally described in 1949 [Fanconi and Bickel(1949); Helv Paediatr Acta 4: 359-396]. FBS is caused by mutations in the glucose and galactose transporter gene SLC2A2 (HGNC ID11006) [Santer et al.(1997); Nat Genet 17: 324-326] and is characterized by hepatic glycogen accumulation with hepatomegaly, fasting hypoglycemia, short stature, impaired glucose tolerance, hyperlipidemia, and tubular nephropathy. Although the described complications would not seem to preclude fertility in FBS patients, there has been no report of reproduction in affected individuals to date. We have followed a female with FBS for at least 20 years. She received a clinical diagnosis in adolescence, with recent molecular confirmation of two mutations in trans in the SLC2A2 gene. She has had glucosuria, proteinuria, impaired tubular reabsorption of phosphate, osteopenia, and hypercholesterolemia throughout her life, without any documented episodes of hypoglycemia. Hepatomegaly was initially noticed in infancy and resolved in late adolescence. She became pregnant at 31 years of age, had gestational diabetes treated with diet, and delivered a healthy boy. She had impaired glucose tolerance after her pregnancy. Her adult height was at the lower end of her target height range, and she had evidence of localized osteopenia at the left distal radius on DXA scan. This report describes the clinical history of an affected individual and highlights the importance of continued follow-up in order to extend our understanding of the history of this rare metabolic disorder.