A novel point mutation at donor splice-site in intron 42 of type III collagen gene resulting in the inclusion of 30 nucleotides into the mature mRNA in a case of vascular type of Ehlers-Danlos syndrome

Abstract

Vascular type of Ehlers-Danlos syndrome (EDS) is the most severe type of EDS. It is an autosomal dominantly inherited disorder that results from mutations within the alpha1 type III collagen gene (COL3A1). We report a novel point mutation at donor splice-site in intron 42 of type III collagen gene resulting in the inclusion of 30 nucleotides into the mature mRNA in a case of vascular type of EDS. Since the age of approximately 8 months, the patient had had repeated episodes of purpura and gradually developed thin, translucent skin. She had a past history of pneumothorax. At the initial examination, she was found to have the characteristic facies, i.e., bird-like face, of the vascular type of EDS, thinning of skin over the limbs and trunk, and scattered purpura. The blood vessels under the skin could be clearly visualized. She showed hypermobility of the small joints of all the four limbs and acrogeric changes of the hands and feet. Analysis of the amount of collagen synthesized from cultured dermal fibroblasts by SDS-polyacrylamide gel electrophoresis and fluorography was conducted based on the clinical suspicion of the vascular type of EDS, and a marked reduction in the synthesis of type III collagen was observed. Genetic analysis of the COL3A1 revealed a novel point mutation at the donor splice-site of intron 42, which resulted in the inclusion of 30 nucleotides into the mature mRNA of one allele.