Gene diagnosis of X-linked spondyloepiphyseal dysplasia tarda

Abstract

ObjectiveTo investigate the molecular pathogenesis of a pedigree of X-linked spondyloepiphyseal dysplasia atarda (SEDL) and to establish methods of gene diagnosis. Methods Clinical diagnosis was made based on height measurement, radiological examination and pedigree analysis. Peripheral blood samples of relevant family members were collected. After genomic DNA extraction, single strand conformation polymorphism (SSCP) followed with DNA sequencing was used to detect SEDL gene exons 36. Microsatellite marker DXS16 was selected for linkage analysis. Results The abnormal electrophoretic bands were detected in exon 4 of probands by PCR-SSCP. A c. 218C ＞ T mutation in exon 4 of SEDL gene was found in three probands, which resulted in a change in amino acid sequence S37L. The heterozygous exon 4 mutation was identified in three carriers, but not in healthy individuals, and no mutations were detect in exon 3, 5 and 6 of probands. Three unmarried young females (Ⅲ10, Ⅳ6 and Ⅳ7) were found to harbor the mutation by DNA sequencing analysis. ConclusionsA c. 218C ＞ T missense mutation in exon 4 of SEDL gene is the cause of molecular pathogenesis of the pedigree. SSCP and DNA sequencing can be used for prenatal gene diagnosis. Key words: Osteochondrodysplasias; Pedigree; Transcription factors; Membrane transport proteins; Polymerase chain reaction; Polymorphism,single-stranded conformational