Inherited Fanconi syndrome

Background Fanconi-Debré-de Toni syndrome(also known as Fanconi renotubular syndrome,or FRST)profoundly increased the understanding of the functions of the proximal convoluted tubule(PCT)and provided important insights into the pathophysiology of several kidney diseases and drug toxicities.Data sources We searched Pubmed and Scopus databases to find relevant articles about FRST.This review article focuses on the physiology of the PCT,as well as on the physiopathology of FRST in children,its diagnosis,and treatment.Results FRST encompasses a wide variety of inherited and acquired PCT alterations that lead to impairment of PCT reab-sorption.In children,FRST often presents as a secondary feature of systemic disorders that impair energy supply,such as Lowe's syndrome,Dent's disease,cystinosis,hereditary fructose intolerance,galactosemia,tyrosinemia,Alport syndrome,and Wilson's disease.Although rare,congenital causes of FRST greatly impact the morbidity and mortality of patients and impose diagnostic challenges.Furthermore,its treatment is diverse and considers the ability of the clinician to identify the correct etiology of the disease.Conclusion The early diagnosis and treatment of pediatric patients with FRST improve the prognosis and the quality of life.

Fanconi-Bickel syndrome in an infant with cytomegalovirus infection: A case report and review of the literature

BACKGROUND Fanconi–Bickel syndrome(FBS)is a rare autosomal recessive disorder caused by mutation of the SLC2A2 gene,which encodes glucose transporter protein 2(GLUT2).CASE SUMMARY We report a 7-mo-old girl with cytomegalovirus infection presenting hepatomegaly,jaundice,liver transaminase elevation,fasting hypoglycemia,hyperglycosuria,proteinuria,hypophosphatemia,rickets,and growth retardation.After prescription of ganciclovir,the levels of bilirubin and alanine aminotransferase decreased to normal,while she still had aggravating hepatomegaly and severe hyperglycosuria.Then,whole exome sequencing was conducted and revealed a homozygous c.416delC mutation in exon 4 of SLC2A2 inherited from her parents,which was predicted to change alanine 139 to valine(p.A139Vfs*3),indicating a diagnosis of FBS.During the follow-up,the entire laboratory test returned to normal with extra supplement of vitamin D and corn starch.Her weight increased to normal range at 3 years old without hepatomegaly.However,she still had short stature.Although there was heterogeneity between phenotype and genotype,Chinese children had typical clinical manifestations.No hot spot mutation or association between severity and mutations was found,but nonsense and missense mutations were more common.Data of long-term follow-up were rare,leading to insufficient assessment of the prognosis in Chinese children.CONCLUSION FBS is a rare genetic metabolic disease causing impaired glucose liver homeostasis and proximal renal tubular dysfunction.Results of urine and blood testing suggesting abnormal glucose metabolism could be the clues for FBS in neonates and infants.Genetic sequencing is indispensable for diagnosis.Since the diversity of disease severity,early identification and long-term follow-up could help improve patients’quality of life and decrease mortality.