Background: Tetralogy of Fallot (TOF) is the most common cyanotic
congenital heart defect (CHD) with an incidence of 1/3600 live births.
This disorder was associated with mutations in the transcription
factors involved in cardiogenesis, like Nk2 homeobox5 (NKX2-5), GATA
binding protein4 (GATA4) and T-BOX1 (TBX1). GATA4 contributes
particularly to heart looping and differentiation of the second heart
field. Objectives: The aim of this study was to screen a Moroccan
cohort with tetralogy of Fallot for GATA4 mutations, and to assess
environmental risk factors that could be involved in the occurrence of
this disorder. Methods: Thirty-one non-syndromic TOF patients, enrolled
between 5th April 2014 and 18th June 2015, were screened for GATA4
mutations using direct sequencing of GATA4 coding exons. Statistical
assessment of different risk factors, which is a retrospective study,
was carried out using Chi-square and Fisher\u2019s exact tests.
Results: We identified seven exonic variants in nine patients (two
missense and five synonymous variants); in addition of eight intronic
variants. Assessment of environmental risk factors shows significant
association of maternal passive smoking with TOF in the Moroccan
population. Conclusion: The present study allowed, for the first time,
the molecular and environmental characterisation of Moroccan TOF
population. Our findings emphasise particularly the strong association
of passive smoking with the emergence of tetralogy of Fallot