Molecular genetic testing for congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is offered worldwide and is of importance for differential diagnosis, carrier detection and adequate genetic counseling, particularly for family planning. In 2008 the European Molecular Genetics Quality Network (EMQN) for the first time offered a European-wide external quality assessment scheme for CAH (due to 21-OH deficiency). The interest was great and over the last years at about 60 laboratories from Europe, USA and Australia regularly participated in that scheme. These best practice guidelines were drafted on the basis of the extensive knowledge and experience got from those annually organized CAH-schemes. In order to obtain the widest possible consultation with practicing laboratories the draft was therefore circulated twice by EMQN to all laboratories participating in the EQA-scheme for CAH genotyping and was updated by that input. The present guidelines address quality requirements for diagnostic molecular genetic laboratories, as well as criteria for CYP21A2 genotyping (including carrier-testing and prenatal diagnosis). A key aspect of that article is the use of appropriate methodologies (e.g., sequencing methods, MLPA (multiplex ligation dependent probe amplification), mutation specific assays) and respective limitations and analytical accuracy. Moreover, these guidelines focus on classification of variants, and the interpretation and standardization of the reporting of CYP21A2 genotyping results. In addition, the article provides a comprehensive list of common as well as so far unreported CYP21A2-variants.

由 21-羟化酶缺乏症 (21-OHD) 引起的先天性肾上腺增生 (CAH) 的分子遗传学检测在全球范围内提供，对于鉴别诊断、携带者检测和充分的遗传咨询，尤其是计划生育，具有重要意义。2008 年，欧洲分子遗传学质量网络 (EMQN) 首次为 CAH（由于 21-OH 缺陷）提供了欧洲范围的外部质量评估方案。人们对此非常感兴趣，在过去几年中，来自欧洲、美国和澳大利亚的大约 60 个实验室定期参与该计划。这些最佳实践指南是根据从每年组织的 CAH 计划中获得的广泛知识和经验起草的。因此，为了与实践实验室进行尽可能广泛的协商，EMQN 向所有参与 CAH 基因分型 EQA 计划的实验室分发了该草案两次，并根据该意见进行了更新。本指南涉及诊断分子遗传实验室的质量要求，以及诊断标准CYP21A 2 基因分型（包括携带者检测和产前诊断）。该文章的一个关键方面是使用适当的方法（例如，测序方法、MLPA（多重连接依赖探针扩增）、突变特异性测定）以及各自的局限性和分析准确性。此外，这些指南侧重于变异的分类，以及CYP21A2基因分型结果报告的解释和标准化。此外，该文章提供了常见的以及迄今为止未报告的CYP21A2变体的综合列表。