Mutational Analysis of <i>ACTN4</i>, Encoding α-Actinin 4, in Patients with Focal Segmental Glomerulosclerosis Using HRM Method

Šafaříková, Markéta; Reiterová, J.; Šafránková, H.; Štekrová, J.; Zidková, A.; Obeidová, L.; Kohoutová, M.; Tesař, V.

doi:10.14712/fb2013059030110

Folia Biologica > Archive > 2013, Vol. 59 > Issue 3 > Mutational Analysis of ACTN4,…

Fol. Biol. 2013, 59, 110-115

https://doi.org/10.14712/fb2013059030110

Mutational Analysis of ACTN4, Encoding α-Actinin 4, in Patients with Focal Segmental Glomerulosclerosis Using HRM Method

Markéta Šafaříková¹, J. Reiterová^1,2, H. Šafránková², J. Štekrová¹, A. Zidková^1,2, L. Obeidová^1,2, M. Kohoutová¹, V. Tesař²

¹Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic
²Department of Nephrology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic

Received December 2012
Accepted January 2013

α-Actinin 4, encoded by ACTN4, is an F-actin crosslinking protein which belongs to the spectrin gene superfamily. It has a head-to-tail homodimer structure with three main domains. Mutations in ACTN4 are associated with idiopathic nephrotic syndrome (NS). However, until today only a few mutations have been described in this gene. We used genomic DNA of 48 patients with focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) to screen for ACTN4 mutations by high-resolution melting analysis (HRM). Suspect samples were sequenced and compared with healthy controls. To investigate the prevalence and possible effect of some substitutions found in FSGS/MCD patients we also looked for these changes in patients with IgA nephropathy (IgAN) and membranous glomerulonephritis (MGN). We found 20 exonic and intronic substitutions in the group of 48 Czech patients. The substitution 2242A>G (p.Asn748Asp) is a candidate mutation which was identified in one patient but not in any of the 200 healthy controls. Exon 19 seems to be a variable region due to the amount of revealed polymorphisms. In this region we also found three unreported substitutions in IgAN patients, c.2351C>T (p.Ala784Val), c.2378G>A (p.Cys793Tyr) and c.2393G>A (p.Gly798Asp). These substitutions were not found in any tested healthy controls. To conclude, the ACTN4 mutations are not a frequent cause of FSGS/MCD in Czech adult patients. One new ACTN4 mutation has been identified.

Keywords

focal segmental glomerulosclerosis, minimal change disease, α-actinin 4, mutational analysis, high-resolution melting method.

Funding

This work was supported by research projects IGA NR 94274/2007 from the Ministry of Health of the Czech Republic and PRVOUK- P25/LF1/2 (Charles University in Prague).