Genetic Abnormalities Associated with Congenital Heart Diseases: A Descriptive Study

Background and Aims: Congenital heart diseases (CHD) are the most common type of birth defect and result in significant mortality worldwide. The etiology of the majority of these anomalies remains unknown, but genetic factors are being recognized as playing an increasingly important role.
Aim: To highlight the role of genetic in CHD and to describe the genetic syndrome involving CHD.

Methods: It was a 17-year retrospective descriptive study.
We identified newborns with CHD supported in Resuscitation and Intensive Care Unit of Neonatology of Military Hospital of Tunis between 2002 and 2018. We studied perinatal database, clinical and paraclinical features, especially genetic study.

Results: We identified 157 newborns with CHD, 26 (16.5%) were associated with chromosomal abnormalities. It was number abnormalities in 22 of 26 and structure ones in 4 of 26. Trisomy 21 was the most frequent chromosomal anomaly (16/26), followed by Trisomy 18 (4/26).
Antenatal diagnosis was performed for eight fetuses. For the others cases, diagnosis was done in the early neonatal period.
Atrioventricular septal defects were the most frequent CHD associated with chromosomal abnormalities (7/26), especially with Down syndrome (7/16). We identified two cases of Tetralogy of Fallot associated with Di-George Syndrome (translocation 22 q11), one case of 7q11.13 microdeletion, and one case of 7q deletion.
Otherwise, CHD was a part of syndromic entity with possible genetic determinism in five cases: Dandy Walker Syndrome (2 cases), VACTERL Syndrome (one), Pierre Robin Syndrome (one case) and a case with nonspecific polymalformative Syndrome.
Eight of 31 newborns needed resuscitation with respiratory assistance. Twelve of the 31 newborns dead. CHD and/or severe malformative syndrome was the direct cause of death for 11/12 newborns.

Conclusions: Antenatal diagnosis is still insufficient in our context, especially for CHD. That may led to the birth of severely, malformed neonates with ethic problem of palliative resuscitation until a clear diagnosis. Genetic counseling is necessary if genetic anomaly is found, but not always easy because of clinical variability of some syndromes.