Hala M. Koura, Nagwa Abdallah Ismail, Ashraf F. Kamel, Azza M. Ahmed, Amal Saad-Hussein, Laila K. Effat The aim of this study 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 res- tricted diet for bone mineralization and to search for a possible relationship between BMD, dietary control, and blood phenylalanine (phe) concen- trations. Material and methods Our study included 32 patients with phenyl- ketonuria recruited from the Association of Genetic and Metabolic Disorders and studied in the paediatric clinic of the National Research Centre (NRC). Nineteen males and thirteen females were diagnosed clinically by fair hair and complexion, and developmental and mental retardation. A history of an affected sibling diagnosed with PKU developed the awareness in families to seek neonatal diagnosis. The diagnosis was confirmed by measu- rement of the blood phe level. The mean age of the patients was 8.6 ±4.7 years, and at the end of the study was 10.7 ±4.9 years. The study period was from January 2007 to January 2009. The selected patients were receiving a low protein diet consisting of low protein breads and pastas (wheat starch, Metamucil and methylcellulose), phenylalanine free formulas, fresh fruits and vegetables [14]. A control group of 42 age- and sex-matched Egyptian children was also included in the study. Informed consent was obtained from the parents of the children according to the guidelines of the ethical committee of NRC, Dokki, Egypt. All patients were subjected to the following: detailed history and clinical examination including pedigree analysis noting the presence of consan- guinity and family history of (PKU), age of diagnosis and duration of diet compliance, pattern of compliance (off diet, irregular or continuous compliance), and developmental milestones (namely: age of head support, mother recognition, sitting ,walking, and age of speech) [15]. The follow- up clinical visit for each patient was monthly, monitoring the growth status, phe level and diet compliance; diet adherence was determined based on the patient’s report. Meticulous chest, heart, abdomen, and neurological examinations were done throughout the study period. Anthropometric measurements: The weight was measured to the nearest 0.1 kg with a digital balance and with the patients in light clothes and without shoes. Height was measured to the nearest 0.5 cm with a stadiometer. Body mass index was calculated as weight divided by height squared for each patient (kg/m2). These parameters were adjusted to age and compared to Egyptian and CDC (Centre for Disease Control and Prevention) reference growth values and taken twice at the same time of each DEXA with statistical comparison between the 2 readings [16]. Bone mineral density and bone mineral content (BMC) were checked by dual-energy x-ray absorp- tiometry (DEXA) [17]. The Norland densitometer (XR-46, USA) Rev. 3.9.6/2.3.1 was used for BMD assessment. Oral sedation was required in 10 patients and the maximum time required for each evaluation was about 15 min. Bone mineral density for each patient was expressed in g/cm2 and BMC in g, both from the lumbar vertebrae (L2-L4) and the femoral neck. Results were expressed as Z-score, the standard deviation (SD) from normal mean BMD for an age- and sex-matched Egyptian paediatric population. An abnormal DEXA was defined as more than one SD below the normal mean, expressed as Z-score < –1. Low BMD (osteopenia) was defined as Z-score from –1 to –2; very low BMD (severe osteopenia) was defined as Z-score from –2 to –2.5 and osteoporosis < –2.5 or spontaneous fracture [13, 18]. The DEXA was done at baseline and follow-up study with statistical comparison between them. Blood phenylalanine level was measured monthly by ELISA using the dried blood spot test. The mean of the two readings was recorded at the time of each DEXA with statistical comparison between them. Statistical analysis The results were computerized and analysed statistically using SPSS version 14.0. Results were expressed as means ± standard deviation (SD). Independent t-test was used to compare between two groups and analysis of variance test (ANOVA) was used for the comparisons between more than two groups. Paired t-test was used to detect the changes in the quantitative data after diet for 2 years. Pearson correlation coefficient was used to determine the relationships between the quantitative variables. The level of significance was considered at p-value < 0.05. Results The comparison between patients and controls at the start of this study for age, weight, height, body mass index (BMI), weight for age Z-score (WAZ), height for age Z-score (HAZ) and BMI percentiles is displayed in Table I. The WAZ and HAZ were significantly lower than controls (p < 0.005). Regarding the BMI percentile a statistical comparison was done between the Egyptian and CDC percentiles and the difference was not statistically significant (mean 50.4 ±5.18 and 59.2 ±5.20 respectively in 2007; mean 62.2 ±4.17 and 70 ±4.58 respectively in 2009). The p value in both was > 0.05. 494 Arch Med Sci 3, June / 2011