Rumsby G, Skinner C, Lee H A, Honour J W
Department of Chemical Pathology, University College and Middlesex School of Medicine, London, UK.
Clin Endocrinol (Oxf). 1993 Oct;39(4):483-5. doi: 10.1111/j.1365-2265.1993.tb02397.x.
To determine the genetic defect underlying congenital adrenal hyperplasia due to 17 alpha-hydroxylase deficiency in a genetic female.
Blood samples were used as a source of genomic DNA. A library of size selected genomic DNA sequences was prepared. In addition, portions of the 17 alpha-hydroxylase gene were amplified by the polymerase chain reaction and the gene products sequenced.
Samples were obtained from a patient with sexual infantilism, lack of secondary sexual characteristics and hypertension. Streak gonads were found on laparoscopy.
Two point mutations were found, one in exon 3 and one in exon 4 which generate premature stop codons at codons 194 and 239 in place of glutamate and arginine respectively. The mutation in exon 3 has not previously been reported in patients with 17 alpha-hydroxylase deficiency.
The protein product of these defective genes could be expected to be severely truncated with no catalytic activity. This is in keeping with the complete lack of cortisol and sex steroid output in this patient. The polymerase chain reaction provides faster access to gene sequence information than previous procedures based on library screening prior to sequencing.
确定一名遗传女性因17α-羟化酶缺乏所致先天性肾上腺皮质增生症的潜在基因缺陷。
以血样作为基因组DNA的来源。制备了一个经大小选择的基因组DNA序列文库。此外，通过聚合酶链反应扩增17α-羟化酶基因的部分片段并对基因产物进行测序。
样本取自一名患有性幼稚症、缺乏第二性征且患有高血压的患者。腹腔镜检查发现条索状性腺。
发现两个点突变，一个在外显子3，一个在外显子4，分别在密码子194和239处产生提前终止密码子，分别取代了谷氨酸和精氨酸。外显子3中的突变以前在17α-羟化酶缺乏患者中未被报道。
这些缺陷基因的蛋白质产物预计会被严重截短且无催化活性。这与该患者完全缺乏皮质醇和性类固醇分泌相符。与之前基于测序前文库筛选的方法相比，聚合酶链反应能更快获取基因序列信息。
