title: [Utility of bone turnover markers in metabolic bone disease detection in patients with phenylketonuria].
abstract: OBJECTIVE
  Mineral bone disease is more common in phenylketonuric patients. The objectives of this study were to determine the usefulness of biochemical bone markers to identify phenylketonuric patients with mineral bone disease (MBD) and know the underlying bone remodeling alterations.
  
  
  METHODS
  Cross-sectional study of 43 phenylketonuric patients>7 years (range: 7.1-41 years). A nutritional survey was performed and bone alkaline phosphatase (BAP), procollagen type 1 N-terminal propeptide (PNP-1), beta-crosslaps and ratio calcium/creatinine in urine were determined.
  
  
  RESULTS
  A percentage of 20.9 of patients had pathological biochemical bone markers, 90% of them being adults. BAP was decreased in 70% of them and beta-crosslaps in 42.8%. BAP values were more often pathological in phenylketonuric patients with a late diagnosis (41.7 vs. 10.7%; P<.05) and in patients with MBD (60 vs. 14.3%; P<.05). PNP-1 values and calcium/creatinine were similar among all phenylketonuric patients regardless of presenting MBD, late diagnosis or tetrahydrobipterin treatment (enzyme cofactor). Patients with decreased BAP and beta-crosslaps had lower natural protein intake: BAP (0.21 ± 0.13 vs. 0.65 ± 0.65 g/kg; P<.05); beta-crosslaps (0.29 ± 0.23 vs. 0.65 ± 0.66 g/kg; P<.05). None of the tetrahydrobiopterin treated patients showed altered values of BAP, PNP-1 or calcium/creatinine.
  
  
  CONCLUSIONS
  Adult phenylketonuric patients with lower natural protein intake tend to have lower values of BAP, which is a marker that may be useful to identify patients at risk for MBD.
authors.affiliation: Unidad de Diagnóstico y Tratamiento de Enfermedades Metabólicas Congénitas, Servicio de Pediatría, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, A Coruña, España.
authors.forename: Alicia
authors.initials: A
authors.lastname: Mirás
authors.affiliation: Servicio de Laboratorio Central, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, A Coruña, España.
authors.forename: Antonio
authors.initials: A
authors.lastname: Freire Corbacho
authors.affiliation: Servicio de Laboratorio Central, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, A Coruña, España.
authors.forename: Javier
authors.initials: J
authors.lastname: Rodríguez García
authors.affiliation: Unidad de Gastroenterología y Nutrición, Servicio de Pediatría, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, A Coruña, España.
authors.forename: Rosaura
authors.initials: R
authors.lastname: Leis
authors.affiliation: Unidad de Metabolismo, Departamento de Pediatría, Hospital de Cruces, Barakaldo, Vizcaya, España.
authors.forename: Luís
authors.initials: L
authors.lastname: Aldámiz-Echevarría
authors.affiliation: Unidad de Diagnóstico y Tratamiento de Enfermedades Metabólicas Congénitas, Servicio de Pediatría, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, A Coruña, España.
authors.forename: José M
authors.initials: JM
authors.lastname: Fraga
authors.affiliation: Unidad de Diagnóstico y Tratamiento de Enfermedades Metabólicas Congénitas, Servicio de Pediatría, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, A Coruña, España. Electronic address: maria.luz.couce.pico@sergas.es.
authors.forename: María L
authors.initials: ML
authors.lastname: Couce
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000378:metabolism* / Q000652:urine; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000175:diagnosis* / Q000652:urine; D016723:Bone Remodeling / Q000502:physiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D010661:Phenylketonurias / Q000150:complications*; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: Bone mineralization; Densitometry; Densitometría; Fenilcetonuria; Mineralización ósea; Nutrición; Nutrition; Osteopenia; Phenylketonuria; Tetrahidrobiopterina; Tetrahydrobipterin
vernacular_title: Utilidad de los marcadores de remodelado óseo en la detección de enfermedad mineral ósea en pacientes con fenilcetonuria.