Hillman L, Schlotzhauer C, Lee D, Grasela J, Witter S, Allen S, Hillman R
Department of Child Health, Columbia, MO 65212, USA.
Eur J Pediatr. 1996 Jul;155 Suppl 1:S148-52. doi: 10.1007/pl00014234.
Children with phenylketonuria (PKU) obtain a great deal of their protein and mineral intakes from synthetic elemental formulae devoid of phenylalanine. To assess the effect of such diets and/or the disease on bone mineralization, children with PKU were compared to normal children for many parameters of mineral homeostasis and bone mineralization. A total of 11 children with PKU of mean age 10.9 +/- 4.2 years were compared to a large group of normal control children mean age 11.4 +/- 4.2, and an age and sex matched subset (n = 11). Children with PKU had lower serum calcium (9.1 +/- 0.9 vs 10.4 +/- 1.9 mg/dl P < 0.01) amd magnesium (1.67 +/- 1.4 vs 2.07 +/- 0.16 mg/ dl, P < 0.001) but normal values for phosphorus, zinc, and copper. The percentage tubular reabsorption of phosphorus was increased in PKU (93 +/- 3% vs 88 +/- 6%, P < 0.05) suggesting a lower phosphorus intake and/or absorption. Serum 25-hydroxyvitamin D, parathyroid hormone and 1,25 dihydroxyvitamin D were similar in PKU and control children. Serum albumin and lean body mass by dual energy X-ray absorption were not different suggesting that protein intake was adequate. In the 11 pairs, a decreased bone mineral density was seen for the lumbar spine (0.61 +/- 0.15 vs 0.72 +/- 0.24 P < 0.05), and lower extremities (1.56 +/- 0.30 vs 1.87 +/- 0.56 P < 0.05) by paired t-test. Compared to the total controls and the paired controls, decreases were seen in markers of bone formation; bone alkaline phosphatase, (72 +/- 30 vs 126 +/- 43 P < 0.001), osteocalcin (10.7 +/- 3.4 vs 13.1 +/- 2.0 P < 0.05) and procollagen type I carboxyterminal propeptide. No differences were seen in the bone resorption markers tartrate resistant acid phosphatase and urine Ca/Cr. The changes noted could not be related after age correction to serum phenylalanine levels, protein intake, or mineral intakes. It is unclear whether deficits in bone mineralization relate to the disease process itself or its treatment.
患有苯丙酮尿症（PKU）的儿童从不含苯丙氨酸的合成元素配方奶粉中获取大量蛋白质和矿物质摄入。为了评估此类饮食和/或疾病对骨矿化的影响，将PKU患儿与正常儿童在矿物质稳态和骨矿化的多个参数方面进行了比较。总共11名平均年龄为10.9±4.2岁的PKU患儿与一大组平均年龄为11.4±4.2岁的正常对照儿童以及一个年龄和性别匹配的子集（n = 11）进行了比较。PKU患儿的血清钙（9.1±0.9 vs 10.4±1.9mg/dl，P<0.01）和镁（1.67±1.4 vs 2.07±0.16mg/dl，P<0.001）较低，但磷、锌和铜的值正常。PKU患儿磷的肾小管重吸收百分比增加（93±3% vs 88±6%，P<0.05），提示磷摄入和/或吸收较低。PKU患儿和对照儿童的血清25-羟维生素D、甲状旁腺激素和1,25-二羟维生素D相似。血清白蛋白和通过双能X线吸收法测得的瘦体重无差异，表明蛋白质摄入充足。在11对配对中，通过配对t检验发现腰椎（0.61±0.15 vs 0.72±0.24，P<0.05）和下肢（1.56±0.30 vs 1.87±0.56，P<0.05）的骨密度降低。与总对照组和配对对照组相比，骨形成标志物骨碱性磷酸酶（72±30 vs 126±43，P<0.001）、骨钙素（10.7±3.4 vs 13.1±2.0，P<0.05）和I型前胶原羧基末端前肽降低。骨吸收标志物抗酒石酸酸性磷酸酶和尿钙/肌酐无差异。在校正年龄后，观察到的变化与血清苯丙氨酸水平、蛋白质摄入或矿物质摄入无关。尚不清楚骨矿化不足是与疾病过程本身还是其治疗有关。
