Background: The etiology of TOF is complex and the genesis of TOF has been associated with environmental\nfactors and genetic disorders, including chromosomal anomalies, aneuploidies, 22q11.2 deletion and single-gene\ndisease. Previous literatures have shown that a chromosome alteration in about 30% patients with TOF and recently\npublished articles reported that 22q11.2 deletion syndrome accounts for 16% cases with TOF diagnosed postnatally.\nCMA now is considered as gold standard for detecting genetic anomalies in fetuses with congenital malformations.\nCMA could detect a 6.6â??25% incremental yield of CNVs in CHDs. The aim of this study was to assess the genetic\nanomalies in fetal tetralogy of Fallot (TOF) by using high-definition CMA.\nMethods: This retrospective study reviewed all the fetuses diagnosed with TOF between 2013 and 2018. Prenatal\nultrasongraphic findings, including cardiac angle, and the findings of CMA using Affymetrix CytoScan HD array were\ncollected.\nResults: Ninety-six fetuses with TOF and known genetic results were enrolled. Right aortic arch was the most\ncommon associated anomalies (22.9%). One fetus with trisomy 18, one with 46, XX, t (7;10)(q36;q22), one with 47,\nXYY and five with trisomy 21 were identified. Clinically significant CNVs occurred in 6.8% and uncertain significant\nCNVs in 3.4% fetal TOF with normal karyotype. A total of four cases with 22q11.2 microdeletion and two fetuses\nwith Yq11.223q11.23 microduplication have been identified. Genetic anomalies, including chromosomal aberrations\nand pathogenic CNVs, were significantly higher in the TOF with extracardiac anomaly group than in the TOF\nwithout extracardiac anomaly group (P = 0.005). Abnormal cardiac angle was noticed in 24.0% fetal TOF. Genetic\nanomalies were more common in the TOF with abnormal cardiac angle than with normal cardiac angle (P = 0.001).\nOn the other hand, abnormal cardiac angle was noticed in 64.3% fetal TOF with genetic anomalies while abnormal\ncardiac angle occurred in 17.1% fetal TOF with normal genetic results (P = 0.001).\nConclusions: Genetic testing should be offered, specially using microarray analysis, for the fetal TOF with abnormal\ncardiac angle or extracardiac defects.
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