A novel splice mutation in EXT1 gene of hereditary multiple osteochondroma and analysis of its pathogenic mechanism / 中华检验医学杂志

ABSTRACT

Objective To analyse a novel splice mutation in EXT1 gene of hereditary multiple osteochondroma, and study its pathogenic mechanism.Methods In April of 2013, the proband was hospitalized from the outpatient department with multiple joint deformity for more than 20 years, peripheral blood of the proband and his parents were collected and genomic DNA was extracted .Coding regions and adjacent intron sequences of EXT1/EXT2 genes in genomic DNA of the family members were amplified and sequenced.Bioinformatics was used to analyze the mutation from sequencing .cDNA from peripheral blood of the proband ,the mother and normal control was made respectively as a template for amplifying coding regions of EXT1 gene, and the product was T-A cloned and sequenced.The abnormal transcripts of each group were counted and analyzed using chi square test to study the pathogenic mechanism of the mutation .Results Sequencing results of family members revealed that there was a heterozygous deletion mutation ( c.1284 +2del) in the 5′splice site of intron 4 in EXT1 gene of the proband and his mother .Bioinformatics predicted that exon 4 of EXT1 gene was skipping or spliced aberrantly due to the mutation .T-A clone and sequencing results as well as the statistical analysis suggested that there was a significantly higher proportion of transcripts with skipping exon 4 in the proband and his mother compared with the normal control (P=0.000, P<0.01).Conclusions c.1284+2del in EXT1 gene is reported for the first time internationally , which results in a considerable number of abnormal transcripts with skipping exon 4 in EXT1 gene, thereby influences the normal transcription and translation of EXT1 gene.