Congenital cardiac myopathy in a baby with an apparently balanced translocation t(7;8)(p21.2;g24.1)

Abstract

Balanced translations are generally not associated with congenital abnormalities but there is always a potential risk, especially when it is de novo, but anomalies are reported even when it is familial. We describe a baby girl born full term to a 24 year old G2PO woman with no evaluated risk factor. Pregnancy was unremarkable, but at 37 weeks GA, sonogram showed fetal ascites and the baby was delivered the next day by C-section. Baby was cyanotic and was immediately intubated and placed in a ventilator. Physical examination showed no abnormalities except for abdominal ascites. Fluid was removed and cultured but no virus or other microorganisms were detected. Renal sonogram revealed normal size kidneys. Chest X-Ray showed an enlarged heart. Cardiac anomalies diagnosed were: anterior mal-alignment contruncal ventricular septal defect, large secundum atrial septal defect, dilated and hypo-contractile ventricles, left sided aortic arch, patent ductus arteriosus with left to right shunt, and frequent unifocal premature ventricular contractions.Chromosome analysis showed an apparently balanced translocation between distal 7p and distal 8q, and the karyotype was 46, XX, t(7;8)(p21.2;q24.1). FISH studies using Coatasomes 7 and 8 confirmed this diagnosis. Both parents had normal karyotypes.Congenital abnormalities associated with apparently balanced translocations may be due to minute deletions at breakpoints, disruption of crucial genes or position effect of genes brought together by translocation. Breakpoint 8q24.1 in this patient is within a crucial chromosome region deleted in Langer-Giedion syndrome. Our patient does not show any characteristic features of L-G syndrome but congenital heart disease has been reported in some cases of L-G syndrome. Further molecular studies are needed to identify any disruption or minute deletions of genes at both breakpoints in order to evaluate the genetic imbalance in this case.