A novel deletion mutation accompanied by a point mutation in Lamin A/C gene: Screened from a dilated cardiomyopathy family.

BACKGROUND: There are 30%-40% of patients with dilated cardiomyopathy (DCM) having genetic causes, among which Lamin A and C gene (LMNA) mutation is the second most frequent DCM-related mutation, and Lamin A/C may be involved in the pathogenesis of DCM through the regulation of gene transcription or the direct effect of cell structure. Methods: Echocardiography and electrocardiogram were used to diagnose DCM and arrhythmia in a DCM family. Then, linked mutations on LMNA were screened out by high-throughput sequencing and verified by Sanger sequencing in all research individuals. Meanwhile, Human Genome Variation Society (HGVS) and Integrative Genomics Viewer (IGV) were used to analyse the characteristics of the mutated Lamin A/C protein. Finally, mutated-type and wild-type LMNA plasmid was transfected into AC-16 cardiomyocytes with the form of a lentivirus vector, and its effect on nucleus and actin was studied by immunofluorescence detection.

RESULTS: In this study, we found a new frame-shifted mutation of LMNA (p.Ser414Alafs*66) linked with another point mutation from a DCM family by using High-throughput sequencing, and this deletion mutation led to a truncation of Lamin A/C. By analysing the clinical characteristics of this DCM family, we found that all DCM patients with arrhythmia were carriers of this co-segregation mutation. In the cytological experiment, we found that the mutated-type transfections showed weaker fluorescent intensities on both actin and cell nucleus.

CONCLUSIONS: A co-segregation mutation of LMNA (Point mutation chr1 156107548 c.1712 G>A and truncated frame-shifted mutation chr1 156106086 c.1240delA) was found from a DCM family, and this type of mutation could participate in the pathogenesis of DCM by affecting the expression of actin.