Screening for cytogenetic and molecular chromosome rearrangements in Tunisian children with conotruncal heart defects

Abstract

Background: Conotruncal heart defects are cardiovascular malformations that have most been associated with chromosomal 22q11.2 microdeletion. Methods: To estimate frequency and investigate the clinical features of these microdeletions in unselected patients with conotruncal heart defects, a total of 26 patients originating from southern Tunisia had been prospectively evaluated through cytogenetic and molecular studies. The clinical analysis was performed according to a specific clinical protocol for the diagnosis of congenital cardiovascular malformations. A molecular cytogenetic technique was undertaken by fluorescence in situ hybridization (FISH) using 2 probes: LSI DiGeorge N25 (D22S75) region probe N25/ARSA, and LSI DiGeorge/ VCFS region probe TUPLE1/ARSA. cytogenetic analysis with RHG banding was carried out to detect chromosome rearrangements. All patients have normal karyotype 46,XX or 46,XY. Results: The frequency of the 22q11.2 microdeletion in the subjects carrying conotruncal heart defects with or without extracardiac signs of our series is thus estimated at 3.85% (1/26). Conclusion: The microdeleted subject is carrying a tetralogy of Fallot.