Long-read sequencing: An effective method for genetic analysis of CYP21A2 variation in congenital adrenal hyperplasia

•The LRS method were demonstrated to be able to identify different types of CYP21A2 variation accurately and comprehensively, and determine the junction sites of chimeric genes precisely.•The LRS method can directly present the copy number and cis–trans configuration of CYP21A2 and CYP21A1P on each chromosome, without the need to analyze additional family samples.•The LRS method could hold substantial promise in clinical application as an effective approach for carrier screening and genetic diagnosis of CAH.