Genetic and functional analyses detect an EXT1 splicing pathogenic variant in a Chinese hereditary multiple exostosis (HME) family.

Background: Hereditary multiple exostosis (HME) is an autosomal dominant skeletal disorder characterized by the development of multiple cartilage-covered tumors on the external surfaces of bones (osteochondromas). Most of HME cases result from heterozygous loss-of-function mutations in EXT1 or EXT2 gene.

Methods: Clinical examination was performed to diagnose the patients: Whole exome sequencing (WES) was used to identify pathogenic mutations in the proband, which is confirmed by Sanger sequencing and co-segregation analysis: qRT-PCR was performed to identify the mRNA expression level of EXT1 in patient peripheral blood samples: minigene splicing assay was performed to mimic the splicing process of EXT1 variants in vitro.