title: A long-term study of bone mineral density in patients with phenylketonuria under diet therapy.
abstract: BACKGROUND
  Dietary control of classic phenylketonuria (PKU) needs restriction of natural proteins; adequate protein intake is achieved by adding low phenylalanine (phe) formulae. The adequacy of this diet for normal bone mineralization had not been sufficiently evaluated. Our aim was to evaluate and follow up bone mineral density (BMD) in children and adolescents with PKU within a 2-year time interval to assess the adequacy of a phenylalanine restricted diet for bone mineralization and to search for a possible relationship between BMD, dietary control and blood phenylalanine (phe) concentrations.
  
  
  METHODS
  Thirty-two patients with classic PKU (3-19 years) were evaluated for their bone mineral status using dual energy X-ray absorptiometry (DEXA) both at the beginning (baseline) and the end (follow-up) of the study.
  
  
  RESULTS
  Low BMD was detected in 31.25% at the start and in 6.25% of patients after 2 years follows-up. No relationship was found between BMD and the duration of diet compliance and phe level as well.
  
  
  CONCLUSIONS
  In this study the low BMD detected in our patients was both at baseline and follow-up independent of diet restriction. A yearly DEXA would be highly beneficial for early detection and treatment, thus preventing osteoporosis and decreasing the risk of fractures. We also suggest the importance of searching for new emerging therapies such as enzyme substitution or gene therapy as low protein diet compliance was not enough to maintain normal bone mineral density.
authors.affiliation: Department of Pediatric, National Research Centre, Cairo, Egypt.
authors.forename: Hala M
authors.initials: HM
authors.lastname: Koura
authors.forename: Nagwa
authors.initials: N
authors.lastname: Abdallah Ismail
authors.forename: Ashraf F
authors.initials: AF
authors.lastname: Kamel
authors.forename: Azza M
authors.initials: AM
authors.lastname: Ahmed
authors.forename: Amal
authors.initials: A
authors.lastname: Saad-Hussein
authors.forename: Laila K
authors.initials: LK
authors.lastname: Effat