title: Dietary management of urea cycle disorders: UK practice.
abstract: BACKGROUND
  There is no published data describing UK dietary management of urea cycle disorders (UCD). The present study describes dietary practices in UK inherited metabolic disorder (IMD) centres.
  
  
  METHODS
  Cross-sectional data from 16 IMD centres were collected by a questionnaire describing the management of UCD patients on prescribed protein-restricted diets.
  
  
  RESULTS
  One hundred and seventy-five patients [N-acetylglutamate synthase deficiency, n = 3; carbamoyl phosphate synthase deficiency (CPS), n = 8; ornithine transcarbamoylase deficiency (OTC), n = 75; citrullinaemia, n = 41; argininosuccinic aciduria (ASA), n = 36; arginase deficiency, n = 12] were reported; 70% (n = 123) aged 0-16 years; 30% (n = 52) >16 years. Prescribed median protein intake decreased with age (0-6 months: 2 g kg(-1) day(-1); 7-12 months: 1.6 g kg(-1) day(-1); 1-10 years: 1.3 g kg(-1) day(-1); 11-16 years: 0.9 g kg(-1) day(-1) and >16 years: 0.8 g kg(-1) day(-1)) with little variation between disorders. Adult protein prescription ranged 0.4-1.2 g kg(-1) day(-1) (40-60 g day(-1)). In the previous 2 years, 30% (n = 53) were given essential amino acid supplements (EAAs) (CPS, n = 2; OTC, n = 20; citrullinaemia, n = 15; ASA, n = 7; arginase deficiency, n = 9). EAAs were prescribed for low plasma quantitative essential amino acids (n = 13 centres); inadequate natural protein intake (n = 11) and poor metabolic control (n = 9). From diagnosis, one centre prescribed EAAs for all patients and one centre for severe defects only. Only 3% (n = 6) were given branch chain amino acid supplements. Enteral feeding tubes were used by 25% (n = 44) for feeds and 3% (n = 6) for medications. Oral energy supplements were prescribed in 17% (n = 30) of cases.
  
  
  CONCLUSIONS
  In the UK, protein restriction based on World Health Organization 'safe intakes of protein', is the principle dietary treatment for UCD. EAA supplements are prescribed mainly on clinical need. Multicentre collaborative research is required to define optimal dietary treatments.
authors.affiliation: Royal Hospital for Sick Children Glasgow, Glasgow Royal Infirmary, Glasgow, UK.
authors.forename: S
authors.initials: S
authors.lastname: Adam
authors.forename: H
authors.initials: H
authors.lastname: Champion
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authors.lastname: Daly
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authors.initials: S
authors.lastname: Dawson
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authors.lastname: Dixon
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authors.lastname: Dunlop
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authors.lastname: Eardley
authors.forename: S
authors.initials: S
authors.lastname: Evans
authors.forename: C
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authors.lastname: Ferguson
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authors.lastname: Jankowski
authors.forename: S
authors.initials: S
authors.lastname: Lowry
authors.forename: A
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authors.lastname: MacDonald
authors.forename: C
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authors.lastname: Maritz
authors.forename: A
authors.initials: A
authors.lastname: Micciche
authors.forename: L
authors.initials: L
authors.lastname: Robertson
authors.forename: J
authors.initials: J
authors.lastname: Stafford
authors.forename: A
authors.initials: A
authors.lastname: Terry
authors.forename: R
authors.initials: R
authors.lastname: Thom
authors.forename: K
authors.initials: K
authors.lastname: van Wyk
authors.forename: D
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authors.lastname: Webster
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authors.initials: FJ
authors.lastname: White
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authors.lastname: Wildgoose
mesh_terms: D000293:Adolescent; D000328:Adult; D000597:Amino Acids, Branched-Chain / Q000008:administration & dosage; D000601:Amino Acids, Essential / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004044:Dietary Proteins / Q000008:administration & dosage; D019587:Dietary Supplements; D004046:Dietetics; D004750:Enteral Nutrition; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018529:Nutritional Support / Q000379:methods; D011795:Surveys and Questionnaires; D006113:United Kingdom; D056806:Urea Cycle Disorders, Inborn / Q000178:diet therapy*
chemical_list: D000597:Amino Acids, Branched-Chain; D000601:Amino Acids, Essential; D004044:Dietary Proteins