Ranke M B
Section Pediatric Endocrinology, Children's Hospital, Tuebingen, Germany.
J Endocrinol Invest. 2006;29(1 Suppl):21-6.
About 5% of newborns are classified as small for gestational age (SGA) and of these, 10-15% do not catch up in growth by 2 yr of age. In addition to genetic mutations in the GH-IGF-IGFBP axis, environmental factors may re-program growth during fetal development leading to altered hormone sensitivity. This review summarizes the importance of GH treatment in SGA children. Although GH dose is the most relevant factor for growth response in children born SGA, higher GH doses are needed in SGA subjects to induce a growth response comparable to GH deficient (GHD) patients. Therapeutic difficulties possibly arise from the impaired hormone sensitivity along the GH-IGF-IGFBP axis. Indeed, several observations point towards impaired sensitivity to hormones involved in the GH-IGF-IGFBP axis in children born SGA. The inability to classify SGA patients according to the relative GH and IGF-I concentrations is probably due to the large variation in hormone sensitivity patterns in patients with SGA. Simple laboratory tests need to be established that directly quantify sensitivity to parameters in the GH-IGF-IGFBP axis, such as IGF-I. Adequate additional therapies could in future result in positive effects on co-morbidities associated with IGF-I insensitivity in SGA children in addition to height gain.
约5%的新生儿被归类为小于胎龄儿（SGA），其中10 - 15%在2岁时生长未能追赶上来。除了生长激素（GH）-胰岛素样生长因子（IGF）-胰岛素样生长因子结合蛋白（IGFBP）轴的基因突变外，环境因素可能会在胎儿发育期间重新编程生长，导致激素敏感性改变。本综述总结了GH治疗对SGA儿童的重要性。尽管GH剂量是SGA出生儿童生长反应的最相关因素，但SGA个体需要更高的GH剂量才能诱导出与生长激素缺乏症（GHD）患者相当的生长反应。治疗困难可能源于GH-IGF-IGFBP轴上激素敏感性受损。事实上，多项观察结果表明，SGA出生儿童对GH-IGF-IGFBP轴相关激素的敏感性受损。无法根据相对GH和IGF-I浓度对SGA患者进行分类，可能是由于SGA患者激素敏感性模式差异很大。需要建立简单的实验室检测方法，直接量化对GH-IGF-IGFBP轴参数（如IGF-I）的敏感性。未来，除了增加身高外，适当的额外治疗可能会对SGA儿童中与IGF-I不敏感相关的合并症产生积极影响。
