1.原发性（1）遗传：正常生长激素功能的维持，需要下丘脑GHRH的分泌到GH、IGF-1的分泌，受体效应都要完整，目前下丘脑-垂体-IGF-1轴的多种基因都已发现突变，导致功能障碍，包括与垂体发育有关的基因缺陷、GH、IGF-1的编码基因和受体基因，例如PROP-1、POU1F1、GHRH、GHRH受体、GH、GH受体、IGF-1以及IGF-1受体等。
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