COL2A1 gene mutation of a family with spondyloepiphyseal dysplasia conginita / 医学研究生学报

ABSTRACT

Objective:To investigate a large Chinese family in which 9 patients over 4 generations were diagnosed with a form of autosomal dominant spondyloepimphyseal dysplasia(SEMD).MothodsX-Ray radiograph of proand at 18-month showed absence of secondary ossification centra of femoral heads.His father at 24-year presented severe spondyloepiphyseal changes that principally involved the vertebral bodies,the femoral necks and femoral heads and characterized by generalized platyspondyly with thoracolumbar scoliosis,irregular femoral necks,absent ossification of femoral heads,flat acetabular roofs and coxa vara.The other patients had similar clinical and radiological features.Haplotyping was performed with leukocyte DNA for 5 micosatellite repeat markers from chromosome 12 and the result showed COL2A1 gene as a candidate gene.A total of 54 exons and promoter of COL2A1 gene were amplified and sequenced from all patients and available normal relatives.In addition,exon 23 of COL2A1 gene was amplified and sequenced from 10 controls simultaneously.Results:All patients were identified a 1510(G→A) transition in exon 23 of COL2A1 gene that caused a change from a COL2A1 coding region in available glycine to serine at amino acid position 504.No mutation was found in the normal relatives and 10 controls. Conclusion:The mutation of COL2A1 gene is responsible for this form of SEDC of the family.This is the first familial report of SEDC relating to 1510G→A mutation of COL2A1 gene.The detailed clinical radiogram data will be useful for extending the phenotypic spectrum of type Ⅱcollagenopathies.