Molecular analysis
Informed consent for genetic testing was obtained from the patient’s parents. Whole exome sequencing (WES) was performed in 3billion, Inc (Seoul, South Korea), using genomic DNA isolated from the patient’s whole blood. All exons of all human genes (approximately 22,000) were captured using a Twist Human Core Exome Kit (Twist Bioscience, San Francisco, CA, USA). The captured genomic regions were sequenced using a NovaSeq platform (Illumina, San Diego, CA, USA). Raw genome sequencing data analyses included alignment to the reference sequence (NCBI genome assembly GRCh37; accessed in February 2009). The mean depth of coverage was 100-fold, with 99.2% coverage higher than 10-fold. Variant calling, annotation, and prioritization were performed as previously described (Seo, 2019). Sanger sequencing of the variant identified by exome sequencing was performed for the patient.