title: The first Chinese case report of hereditary folate malabsorption with a novel mutation on SLC46A1.
abstract: BACKGROUND
  Hereditary folate malabsorption is a rare, autosomal recessive disorder of proton-coupled folate transporter deficiency resulting in folate deficiency. Left untreated, the condition can cause severe brain damage and megaloblastic anemia, leading to progressive psychomotor retardation, seizures and other neurological problems. Early diagnosis and treatment are crucial. No case has been documented yet in Mainland China until now.
  
  
  METHODS
  A Chinese girl affected by hereditary folate malabsorption was studied. The girl presented with recurrent megaloblastic anemia from the age of 7 months. Paroxysmal limbs trembling and seizures were presented from the age of three years. Intracranial calcification was noted by CT. At her age of 5 years, mental regression, lower-extremity weakness and sleeping problems were observed. Her plasma folate decreased to 4.49 nmol/L (normal control>6.8nmol/L). Plasma total homocysteine elevated to 28.11 μmol/L (normal control<15 μmol/L). Folate and 5-methylterahydrofolate in cerebrospinal fluid were significantly decreased to undetectable level.
  
  
  RESULTS
  On SLC46A1 gene, a novel mutation, c.1A>T (M1L), and a reported mutation c.194-195 insG (p.Cys66LeufsX99) were identified, supported the diagnosis of hereditary folate malabsorption. Each parent carries one of two mutations. Folinic calcium supplement resulted in rapid clinical improvement. She is currently 6 years old with normal development and routine blood features.
  
  
  CONCLUSIONS
  Hereditary folate malabsorption is one of the few easily-treatable inherited metabolic diseases. Measurements of folate and 5-methyltetrahydrofolate in cerebrospinal fluid are keys for the diagnosis of the patients.
authors.affiliation: Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
authors.forename: Xiyuan
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Similan Clinic, Beijing 100070, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Department of Pediatrics, Peking University First Hospital, Beijing 100034, China. Electronic address: yanlingy@vip.sina.com.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Yang
mesh_terms: D017668:Age of Onset; D044466:Asian People; D002675:Child, Preschool; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use; D005494:Folic Acid Deficiency / Q000150:complications / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008286:Malabsorption Syndromes / Q000150:complications / Q000235:genetics* / Q000473:pathology; D017354:Point Mutation; D058979:Proton-Coupled Folate Transporter / Q000235:genetics*; D012640:Seizures / Q000209:etiology
chemical_list: D058979:Proton-Coupled Folate Transporter; C505058:SLC46A1 protein, human; D005492:Folic Acid
keywords: Cerebral folate deficiency; Hereditary folate malabsorption; Intracranial calcification; Megaloblastic anemia; Proton-coupled folate transporter; SLC46A1 gene