STUDIES ON PSEUDOHYPOPARATHYROIDISM AND RELATED DISORDERS

1942年，奥尔布赖特和他的同事描述了一种新的 临床综合征“假性甲状旁腺功能减退症”（PHP）。 患者与此 疾病表现出典型的体质特征（奥尔布赖特遗传性 骨营养不良（AHO），对外源性甲状旁腺激素无反应 （PTH）。 在PHP中，UcAMP（尿环AMP）在正常情况下不会增加， 对PTH给药的反应。 这表明存在缺陷 激素受体-腺苷酸环化酶复合物。 我们已经表明 许多PHP+AHO（PHP Ia）患者显示约50%的 降低Gs的活性（刺激性鸟嘌呤核苷酸结合 与腺苷酸环化酶相关的蛋白质） 组织中 GS缺乏可能是导致对多种抗生素耐药的原因之一。 激素在这些患者中。 使用克隆的人cDNA探针， 亚基，我们已经表明，从成纤维细胞的稳态mRNA水平， 的PHP Ia受试者减少了约50%， 正常人 我们现在已经成功地确定了 导致G缺乏症 使用聚合酶链反应 扩增包含Gs-alpha基因的每个外显子的基因组片段，和 比较来自正常受试者和受影响受试者的这些片段的变性 梯度凝胶电泳，我们能够识别片段与 异常的流动性。 通过直接DNA测序，这些片段含有 这些突变可以解释受影响受试者中mRNA的减少。

In 1942 Albright and his associates described the features of a new clinical syndrome "pseudohypoparathyroidism" (PHP). Patients with this disorder show characteristic constitutional features (Albright's hereditary osteodystrophy - AHO) and do not respond to exogenous parathyroid hormone (PTH). In PHP, UcAMP (urinary cyclic AMP) does not increase normally in response to PTH administration. This indicates that there is a defective hormone receptor-adenylate cyclase complex in this disorder. We have shown that many patients with PHP+AHO (PHP Ia) show an approximately 50% reduction in activity of Gs (the stimulatory guanine nucleotide binding protein associated with adenylate cyclase) in membranes from multiple tissues. Gs deficiency presumably accounts for resistance to multiple hormones in such patients. Using cloned human cDNA probes for the alpha subunit of Gs, we have shown that steady state mRNA levels from fibroblasts of subjects with PHP Ia are reduced by approximately 50% compared with normals. We have now succeeded in defining the genetic abnormality responsible for Gs deficiency. Using the polymerase chain reaction to amplify genomic fragments encompassing each exon of the Gs-alpha gene, and comparing such fragments from normal and affected subjects on denaturing gradient gel electrophoresis, we were able to identify fragments with abnormal mobility. By direct DNA sequencing such fragments contained mutations that would explain reduction in mRNA in affected subjects.