鸟苷酸环化水解酶Ⅰ是四氢生物喋呤合成途径中的限速酶 ,四氢生物喋呤又是芳香族氨基酸羟化酶的必需辅助因子 ,因此鸟苷酸环化水解酶Ⅰ活性的缺陷将影响苯丙氨酸代谢和单胺类神经递质的合成。不同程度的缺陷导致不同的表现型。鸟苷酸环化水解酶Ⅰ基因突变表达的这种临床异质性 ,很可能与遗传方式、突变类型以及突变组合的差异有关 Guanylyl cyclase I is the rate-limiting enzyme in the tetrahydrobiopterin synthesis pathway and tetrahydrobiopterin is an essential cofactor for aromatic amino acid hydroxylases and therefore guanylate cyclase I activity The defects will affect the phenylalanine metabolism and monoamine neurotransmitter synthesis. Different degrees of defects lead to different phenotypes. This clinical heterogeneity of the guanylate cyclase I gene mutation is likely to be related to the genetic pattern, the type of mutation, and the difference in the combination of mutations