Variant annotation and interpretation
The pathogenicity assessment and data interpretation rules of mutation are based on the guidelines of the American College of Medical Genetics and Genomics (ACMG) (Richards, et al., 2015). By querying 1000genomes, ExAC and gnomAD, we excluded gene mutations whose frequency of the population are more than 1% and removed non-functional mutation sites (such as synonymous mutations, non-coding region mutations, etc.).We performed gene function prediction (using software such as SIFT, Polyphen2, CADD, etc.) and clinical symptoms comparison. At last, we searched related disease databases and related references, and finally found candidate gene mutation sites for family verification. The variant annotation databases which were used include Human Genome hg19/GRCh37, RefSeq, dbSNP, 1000 Genomes phase3, ExAC, and gnomAD and the interpretation databases which were used include DGV, DECIPHER, OMIM, UCSC, ClinVar, HGMD and PubMed.