Coarctation of the aorta in dizygotic twins

Dichorionic Diamniotic Twin Pairs with Complex Congenital Heart Disease

Complex congenital heart disease (CHD) in each of dichorionic diamniotic (DiDi) twin pairs is extremely rare and has not been well characterized. Four DiDi twin pairs were included in this multi-institutional case series. The congenital cardiac abnormalities noted included tetralogy of Fallot (ToF) with pulmonary atresia and collaterals (n = 1), ToF with absent pulmonary valve (n = 1), ToF (n = 2), discontinuous right pulmonary artery (RPA) (n = 1), tricuspid atresia (TA) with normally related great arteries and pulmonary valve stenosis or atresia (n = 2) and coarctation of aorta (CoA) with bicuspid aortic valve (BAV) and borderline left-sided structures (n = 1). Genetic testing was obtained on seven of the eight twins but did not reveal any causal abnormality. A comprehensive review of literature yielded another 8 DiDi twin pairs with complex CHD. The CHD noted in these twin pairs included ToF (n = 2), CoA (n = 4), corrected transposition of great arteries (ccTGA) (n = 2), truncus arteriosus (n = 2), complete common atrioventricular canal (CCAVC) (n = 2), hypoplastic left heart syndrome (HLHS) (n = 2), Shone's complex (n = 1), and hypoplastic right heart syndrome (HRHS) (n = 1). Limited genetic testing was obtained on 4 of these twins and revealed trisomy 21 in a twin pair. Conotruncal abnormalities (42%), CoA (21%), and abnormalities of the right ventricle, the right ventricular outflow tract and pulmonary arteries (17%) are more prevalent in DiDi twins with complex CHD. Clustering of these abnormalities suggests a possible genetic basis; however, genetic testing was obtained on eleven of the twins, and except for trisomy 21 in a twin pair both of whom had CCAVC, did not reveal any causal abnormality. A major direct genetic contribution is therefore unlikely and like other CHD, the underlying etiopathological basis is likely multifactorial.

Twin-twin transfusion syndrome, coarctation of the aorta and hypoplastic aortic arch: a case series report

AIM

The twin-twin transfusion syndrome (TTTS) complicates 10-30% of monochorionic pregnancies. The incidence of pulmonary stenosis and endocardial fibroelastosis is especially high in the recipient twin. We report a novel finding of four cases of coarctation of the aorta and hypoplastic aortic arch in the donor to raise awareness of cardiac lesions in twins affected by TTTS.

METHOD

Retrospective review of both neonatal database and mortality data from 2002 to 2007 with cross-validation from the local tertiary cardiology unit data (1998-2006) to identify children presenting with coarctation who were also twins.

RESULTS

We identified four monochorionic twin pairs affected by the TTTS, delivered between 25 weeks and 36 weeks' gestation, where the donor was found to have coarctation of the aorta or a hypoplastic aortic arch. In addition, two of the four recipients also had cardiac abnormalities. There was a high mortality rate of 30% for both twins, and a high morbidity rate, especially for neurological sequelae.

CONCLUSION

We believe that the types of abnormalities seen may be explained by the altered fetal blood flow and haemodynamics in TTTS. Given the increased prevalence of congenital heart disease in TTTS, with an increased risk of coarctation in the donor twin and pulmonary stenosis in the recipient, intra-uterine surveillance and a post-natal comprehensive cardiac assessment for both twins is warranted.

A cluster of hypoplastic left heart malformation in Baltimore, Maryland

Congenital cardiovascular malformations (CCVMs) of the left side of the heart show familial recurrence of various forms of obstructive malformations, including hypoplastic left heart (HLH), interrupted aortic arch, coarctation of the aorta, and aortic stenosis. In a previous population-based study in the Baltimore-Washington region, these malformations were associated with parental reports of occupational or leisure solvent exposure, overt diabetes, and family history of CCVM in first-degree relatives. Spatial analysis in this well-characterized study population may augment self-reported data by revealing additional associations with potential environmental risk factors. We used spatial analysis to identify clusters of HLH as a group. The study population included all live-born cases of hypoplastic left heart syndrome diagnosed in the first year of life between 1981 and 1989 and a random sample of unaffected infant controls matched by year and hospital of birth. The nested case-control cohort in this spatial analysis included 77 HLH cases and 1894 controls in Maryland and the District of Columbia. Nonparametric and regression analyses included personal variables from the interview data set as well as spatial variables. A region of Baltimore was identified that contained HLH at twice the expected frequency based on the distribution of population younger than 5 years of age. The region included 30 of 77 geocoded cases of HLH in the cohort and is significant by spatial scanning at p = 0.056. Within this region, male cases of HLH were disproportionately present compared to females. This cluster is in a region of Baltimore with industrial release of solvents, dioxin, and polychlorinated biphenyls in air. Outside the cluster, HLH is associated with family history of CCVM in a first-degree relative, maternal exposure to miscellaneous solvents, paternal anesthesia, maternal art painting, aspirin ingestion, and maternal diabetes. Inside the cluster, father's painting and exposure to sympathomimetic drugs were associated risk factors. Spatial analysis of HLH cases delineated an urban region with increased prevalence of this left heart malformation. Within this region, excess male cases of HLH occurred, and industrial release to air of solvents, dioxin, and polychlorinated biphenyl compounds was documented. We propose that both genetic and environmental factors contribute to the phenotype of HLH.

Congenital heart disease in a population of dizygotic twins: an echocardiographic study

BACKGROUND

Congenital heart disease (CHD) is the most common malformation in the fetal and neonatal period but little is known about its cause. The distribution analysis of CHD in dizygotic twins could provide a useful tool to evaluate the role of genetic and environmental factors in the development of CHD. Dizygotic twins are siblings with different genes, growing together in the same womb.

AIM OF STUDY

To investigate the occurrence of CHD in a large sample of dizygotic twins of nonconsanguineous healthy parents, comparing the data from non-twin patients.

METHODS

From January 1999 to December 2002, we enrolled 1743 CHD patients with, at least 1 sibling, and 66 pairs of dizygotic twins, referred to our tertiary center. The diagnosis of CHD was based on clinical and echocardiographic evaluation.

RESULTS

Considering only the sibling nearest in age for each non-twin patient the recurrence was 67/1743 (3.8%). Among these 67 patients, 35 (52.2%) had a sibling with the same or similar CHD. Conversely, considering all 1886 siblings, recurrence of CHD in the non-twin group was 70/1743 (4%). Of the 70 patients, 36 (36/70, 51.4%) had a sibling with the same suspected pathogenic mechanism of CHD. In 9/66 pairs of twins (13.6%), both siblings had a CHD. In the nine pairs of twins in whom both siblings had a CHD, the percentage of concordance (based on the suspected pathogenic mechanism) for CHD was 100% (p<0.05).

CONCLUSIONS

Our findings suggest that the higher recurrence and concordance of CHD found in dizygotic twins could depend on some poorly identified environmental risk during the pregnancy.