AB150. Mutation spectrum of the fibrillin-1 (FBN1) gene in Taiwanese patients with Marfan syndrome
Shu-Chen Hsieh1, Yung-Hsiu Lu1,2, Ya-Chi Chen1, Ju-Shan Pai1, Yu-Ping Hsieh1, Dau-Ming Niu1,2
Background and objective: Marfan syndrome (MFS) is an autosomal dominant genetic disorder that involves in multisystem connective tissues. The various phenotypic manifestations of MFS are skeleton, ocular and cardiovascular system. MFS is mainly caused by mutations in the fibrillin-1 gene (FBN1 gene) on chromosome 15 which contains 66 exons consist of 11,695 bp mRNA and coding 2,872 amino acids. To date, there are more than 1,000 mutations in FBN1 have been registered in Human Gene Mutation Database (HGMD). Mutation scanning of the FBN1 gene with DNA direct sequencing is time-consuming and expensive because of its large size. The aim of this study was to establish a national database of mutations in the fibrillin-1 (FBN1) gene that cause MFS in the Taiwanese population. And we present an alternative method for high-throughput FBN1 gene variant scanning by melting curve analysis with the Roche LightCycler 480 (LC480) system.
Methods: We screened 390 patients from 231 families for the presence of FBN1 mutations using polymerase chain reaction/high-resolution melting analysis (PCR/HRM). All the temperature-shifted melting curves will be analysis by Sanger Sequencing.
Results: We identified 76 mutations in 96 of the 231 (41.5%) families including 69 single-base substitutions (51 missense mutations, 7 nonsense mutations, and 11 splicing sites), one small insertion, four small deletions, one small indel (insertion and deletion), and one exonic deletion (exon 36). When family history and Ghent criteria for MFS were taken into consideration, the mutation detection rate rose to 97% (62/64). That finding implies that family history and the Ghent criteria play a more important role than clinical manifestations in establishing a clinical diagnosis of MFS. Among the 76 mutations found in this study, 13 (17%) have not been registered in the HGMD or in the Universal Mutation Database (UMD).
Conclusions: This is the largest study of the mutation spectrum of MFS in a cohort of patients in Taiwan. The database is expected to considerably improve genetic counselling for and medical care of MFS families. And our results support the use of this technology as an alternative method for the diagnosis of Marfan syndrome as well as its suitability for high-throughput mutation scanning of other large genes.
Keywords: Marfan syndrome (MFS); FBN1 gene, high-resolution melting (HRM); Taiwan
