Short report Search of somatic GATA4 and NKX2.5 gene mutations in sporadic septal heart defects Marleny Salazar a , Federica Consoli b , Victoria Villegas c , Victor Caicedo d , Valeria Maddaloni e , Paola Daniele b , Giuseppe Caianiello e , Sonia Pachón d , Federico Nuñez d , Giuseppe Limongelli e , Giuseppe Pacileo e , Bruno Marino f , Jaime E Bernal g , Alessandro De Luca b, * , Bruno Dallapiccola h a Universidad del Quindío, Armenia, Colombia b Casa Sollievo della Sofferenza Hospital, IRCCS, San Giovanni Rotondo, Italy c Universidad del Rosario, Bogotà, Colombia d Unidad de Cirugía Cardiovascular, Clínica Shaio, Bogotá, Colombia e Department of Cardiology, Monaldi Hospital, Second University of Naples, Naples, Italy f Division of Pediatric Cardiology, Department of Pediatrics, Sapienza University, Rome, Italy g Instituto de Genética Pontificia Universidad Javeriana, Bogotá, Colombia h Bambino Gesù Children Hospital, IRCCS, Rome, Italy article info Article history: Received 22 September 2010 Accepted 17 January 2011 Available online 27 January 2011 Keywords: Congenital heart disease Cardiac septal defect Somatic mutations GATA4 NKX2.5 abstract High prevalence of somatic mutations in the cardiac transcription factor genes NKX2.5 and GATA4 have been reported in the affected cardiovascular tissue of patients with isolated cardiac septal defects, suggesting a role of somatic mutations in the pathogenesis of these congenital heart defects (CHDs). However, all somatic mutations have been identified in DNA extracted from an archive of formalin-fixed cardiac tissues. In the present study, to address the hypothesis that somatic mutations are important in isolated CHDs, we analyzed the GATA4 and NKX2.5 genes in the fresh-frozen pathologic cardiac tissue specimen and corresponding non-diseased tissue obtained from a series of 62 CHD patients, including 35 patients with cardiac septal defects and 27 with other cardiac anomalies. We identified one variant and two common polymorphisms in the NKX2.5 gene, and six variants and two common polymorphisms in the GATA4 gene. All identified variants were seen in both the fresh-frozen pathologic cardiac tissue and the corresponding non-diseased tissue, which indicates that they all were constitutional variants. The present study has identified NKX2.5 and GATA4 constitutional variants in our CHD cohort, but was unable to replicate the previously published findings of high prevalence of somatically derived sequence mutations in patients with cardiac septal defects using fresh-frozen cardiac tissues rather than formalin- fixed tissues. Ó 2011 Elsevier Masson SAS. All rights reserved. 1. Introduction Somatic mosaicism refers to the condition in which a mutation arises after fertilization such that only a subset of cells or tissues harbors the defect. Aside from occupying a major role in the pathogenesis of many cancers, somatic mosaicism has been shown to underlie some cases of certain genetic disorders [1]. This genetic mechanism has been raised theoretically as relevant for congenital heart defects (CHDs), particularly when isolated, and over the last past years the first somatic mutations confined to affected cardiovascular tissue have been reported. Somatic mutations have been found in GJA1 [2], NKX2.5 [3], TBX5 [4], GATA4 [5,6], HEY2 [7] and HAND1 [8,9] genes. Reamon-Buettner and Borlak have reported the majority of somatic mutations in CHDs, including mutations in transcription factors NKX2.5, TBX5, GATA4, HEY2 and HAND1 [3e11]. In particular, NKX2.5 somatic mutations were identified in almost all human hearts with septal heart defects (i.e. 66 of 68 formalin- fixed hearts examined by Reamon-Buettner and Borlak had a somatic sequence variant) [3,11]. Moreover, in several patients different mutations in the same gene with cumulative down- regulation of transcription were reported (up to 14 mutations in patients with ventricular septal defects [VSD]) [3,6,11]. These somatic sequence variants were identified in DNA extracted from the University of Leipzig (Germany) collection of malformed hearts, * Corresponding author. Tel.: þ39 06 44160533; fax: þ39 06 44160548. E-mail address: a.deluca@css-mendel.it (A. De Luca). Contents lists available at ScienceDirect European Journal of Medical Genetics journal homepage: http://www.elsevier.com/locate/ejmg 1769-7212/$ e see front matter Ó 2011 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.ejmg.2011.01.004 European Journal of Medical Genetics 54 (2011) 306e309