Primary immunodeficiency diseases (PIDs) are composed by a group of highly heterogeneous immune system diseases, of which approximately 350 forms of PID have been described so far. The causative gene of around 60% of patients with PIDs has yet unknown. In recent years, Next Generation Sequencing (NGS) has been increasingly adopted for gene identification and molecular diagnosis of rare diseases, including PIDs. An overview of the genetic makeup that underlies PID using NGS has been suggested as a promising approach to elucidate the etiology of PIDs, which could yield diagnostic and, possibly, provide new treatment advances for PID.To approach this goal, we performed either whole exome sequencing (WES, 454 samples) or targeted region sequencing (TRS, 217 samples) on 602 samples of 500 PID pedigrees. We have summarized the practical suggestions for the interpretation of NGS data and the techniques that can be used to search disease-causative PID genes in Paper I. This work aims to improve data annotation, interpretation, and application of NGS data in PIDs, which also facilitates a wide range of application of NGS data analysis in other Mendelian disorders.