Currently, more than 12,000 monogenic diseases have been reported worldwide. According to the statistics of the World Health Organization, the incidence rates of most monogenic diseases are 0.65%-1%, and the total incidence rate exceeds 1%. The number of patients with monogenic genetic diseases worldwide has reached up to 20 million. Among them, the patients with severe or intermediate thalassemia number about 0.3 million. The number of carriers with thalassemia variants is up to 30 million. Exome is the sum of all protein coding sequences on an individual's genomic DNA. The human exon group sequence accounts for only 1% of the entire human genome sequence, approximately 30Mb, including approximately 180000 exons, but it is closely related to the occurrence of various diseases. It is estimated that 85% of human pathogenic mutations are located on these 1% protein coding sequences.

Whole exome sequencing can effectively help us clarify the genetic factors of monogenic diseases, deeply explore the internal relationship between diseases and genetic variations, and provide more scientific guidance for carriers and patients’ families.