title: Dietary practices in pyridoxine non-responsive homocystinuria: a European survey.
abstract: BACKGROUND
  Within Europe, the management of pyridoxine (B6) non-responsive homocystinuria (HCU) may vary but there is limited knowledge about treatment practice.
  
  
  OBJECTIVE
  A comparison of dietetic management practices of patients with B6 non-responsive HCU in European centres.
  
  
  METHODS
  A cross-sectional audit by questionnaire was completed by 29 inherited metabolic disorder (IMD) centres: (14 UK, 5 Germany, 3 Netherlands, 2 Switzerland, 2 Portugal, 1 France, 1 Norway, 1 Belgium).
  
  
  RESULTS
  181 patients (73% >16 years of age) with HCU were identified. The majority (66%; n=119) were on dietary treatment (1-10 years, 90%; 11-16 years, 82%; and >16 years, 58%) with or without betaine and 34% (n=62) were on betaine alone. The median natural protein intake (g/day) on diet only was, by age: 1-10 years, 12 g; 11-16 years, 11 g; and >16 years, 45 g. With diet and betaine, median natural protein intake (g/day) by age was: 1-10 years, 13 g; 11-16 years, 20 g; and >16 years, 38 g. Fifty-two percent (n=15) of centres allocated natural protein by calculating methionine rather than a protein exchange system. A methionine-free l-amino acid supplement was prescribed for 86% of diet treated patients. Fifty-two percent of centres recommended cystine supplements for low plasma concentrations. Target treatment concentrations for homocystine/homocysteine (free/total) and frequency of biochemical monitoring varied.
  
  
  CONCLUSIONS
  In B6 non-responsive HCU the prescription of dietary restriction by IMD centres declined with age, potentially associated with poor adherence in older patients. Inconsistencies in biochemical monitoring and treatment indicate the need for international consensus guidelines.
authors.affiliation: Glasgow Royal Infirmary, Royal Hospital for Sick Children, UK.
authors.forename: S
authors.initials: S
authors.lastname: Adam
authors.forename: M F
authors.initials: MF
authors.lastname: Almeida
authors.forename: E
authors.initials: E
authors.lastname: Carbasius Weber
authors.forename: H
authors.initials: H
authors.lastname: Champion
authors.forename: H
authors.initials: H
authors.lastname: Chan
authors.forename: A
authors.initials: A
authors.lastname: Daly
authors.forename: M
authors.initials: M
authors.lastname: Dixon
authors.forename: K
authors.initials: K
authors.lastname: Dokoupil
authors.forename: D
authors.initials: D
authors.lastname: Egli
authors.forename: S
authors.initials: S
authors.lastname: Evans
authors.forename: F
authors.initials: F
authors.lastname: Eyskens
authors.forename: A
authors.initials: A
authors.lastname: Faria
authors.forename: C
authors.initials: C
authors.lastname: Ferguson
authors.forename: P
authors.initials: P
authors.lastname: Hallam
authors.forename: M
authors.initials: M
authors.lastname: Heddrich-Ellerbrok
authors.forename: J
authors.initials: J
authors.lastname: Jacobs
authors.forename: C
authors.initials: C
authors.lastname: Jankowski
authors.forename: R
authors.initials: R
authors.lastname: Lachmann
authors.forename: R
authors.initials: R
authors.lastname: Lilje
authors.forename: R
authors.initials: R
authors.lastname: Link
authors.forename: S
authors.initials: S
authors.lastname: Lowry
authors.forename: K
authors.initials: K
authors.lastname: Luyten
authors.forename: A
authors.initials: A
authors.lastname: MacDonald
authors.forename: C
authors.initials: C
authors.lastname: Maritz
authors.forename: E
authors.initials: E
authors.lastname: Martins
authors.forename: U
authors.initials: U
authors.lastname: Meyer
authors.forename: E
authors.initials: E
authors.lastname: Müller
authors.forename: E
authors.initials: E
authors.lastname: Murphy
authors.forename: L V
authors.initials: LV
authors.lastname: Robertson
authors.forename: J C
authors.initials: JC
authors.lastname: Rocha
authors.forename: I
authors.initials: I
authors.lastname: Saruggia
authors.forename: P
authors.initials: P
authors.lastname: Schick
authors.forename: J
authors.initials: J
authors.lastname: Stafford
authors.forename: L
authors.initials: L
authors.lastname: Stoelen
authors.forename: A
authors.initials: A
authors.lastname: Terry
authors.forename: R
authors.initials: R
authors.lastname: Thom
authors.forename: T
authors.initials: T
authors.lastname: van den Hurk
authors.forename: M
authors.initials: M
authors.lastname: van Rijn
authors.forename: A
authors.initials: A
authors.lastname: van Teefelen-Heithoff
authors.forename: D
authors.initials: D
authors.lastname: Webster
authors.forename: F J
authors.initials: FJ
authors.lastname: White
authors.forename: J
authors.initials: J
authors.lastname: Wildgoose
authors.forename: H
authors.initials: H
authors.lastname: Zweers
mesh_terms: D000293:Adolescent; D000328:Adult; D001622:Betaine / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D018753:Diet, Protein-Restricted; D005060:Europe; D005260:Female; D006710:Homocysteine / Q000097:blood; D006712:Homocystinuria / Q000097:blood / Q000178:diet therapy* / Q000453:epidemiology / Q000473:pathology; D006801:Humans; D007223:Infant; D008297:Male; D008715:Methionine / Q000378:metabolism; D011736:Pyridoxine / Q000378:metabolism*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
chemical_list: D006710:Homocysteine; D001622:Betaine; D008715:Methionine; D011736:Pyridoxine
keywords: Betaine; Homocysteine; Homocystinuria; Methionine; Protein restricted diet