Tetralogy of Fallot with pulmonary atresia in siblings

The Contribution of Gene Mutations to the Pathogenesisof Tetralogy of Fallot

Congenital heart disease (CHD) is considered as an important and developing area in the medical community. Since these patients can reach maturity and have children, the role of genetic determinants in increasing risk of CHD is extremely evident among children of these patients. Because genetic studies related to CHD are increasing, and each day the role of new genetic markers is more and more clarified, this review re-examined the effects of gene mutations in the pathogenesis of tetralogy of Fallot (TOF) as an important pathological model among other CHDs. Due to the complexity of heart development, it is not astonishing that numerous signaling pathways and transcription factors, and many genes are involved in pathogenesis of TOF. This review focuses on the jag1, nkx2.5, gata4, zfpm2/fog2 and cited2 genes previously reported to be involved in TOF.

Jagged1 (JAG1) mutations in patients with tetralogy of Fallot or pulmonic stenosis

Mutations in the Notch pathway ligand Jagged1 (JAG1) cause Alagille syndrome (AGS), as well as cardiac defects in seemingly nonsyndromic individuals. To estimate the frequency of JAG1 mutations in cases with right-sided cardiac defects not otherwise diagnosed with AGS, we screened 94 cases with tetralogy of Fallot (TOF) and 50 with pulmonic stenosis/peripheral pulmonary stenosis (PS/PPS) or pulmonary valve atresia with intact ventricular septum (PA) for mutations. Sequence changes were identified in three TOF and three PS/PPS/PA patients, that were not present in 100 controls. We identified one frameshift and two missense mutations in the TOF cases, and one frameshift and two missense mutations in cases with PS/PPS/PA. The four missense mutations were assayed for their effect on protein localization, posttranslational modification, and ability to activate Notch signaling. The missense mutants displayed heterogeneous behavior in these assays, some with complete haploinsufficiency, suggesting that there are additional modifiers leading to organ specific features. We identified functionally significant mutations in 2% (2/94) of TOF patients and 4% (2/50) of PS/PPS/PA patients. Patients with right-sided cardiac defects should be carefully screened for features of AGS or a family history of cardiac defects that might suggest the presence of a JAG1 mutation.

Prenatal diagnosis of absent pulmonary valve syndrome in association with 22q11 deletion

OBJECTIVE

To describe the prenatal sonographic appearances in cases of absent pulmonary valve syndrome and the importance of investigating the presence of 22q11 deletion.

METHODS

We describe 2 cases, which were referred because of a suspicion of a cardiac malformation. In both cases, a large anechoic mass emerging from the right ventricle was visualized and identified as an aneurysmal dilatation of the pulmonary trunk with hypertrophy of the right ventricle. The diagnosis of tetralogy of Fallot with absent pulmonary valve syndrome and a secondary diverticular dilatation of the pulmonary artery was made. A review of the literature revealed another 18 cases of prenatal diagnosis of absent pulmonary valve syndrome with or without knowledge of chromosomal abnormalities.

RESULTS

Pathologic examinations confirmed the diagnosis of absent pulmonary valve syndrome in both cases. Final results of fetal karyotyping revealed a 22q11 deletion in the first case.

CONCLUSIONS

An abnormal 4-chamber view with an aneurysmal dilatation of the pulmonary trunk should suggest the diagnosis of this rare congenital anomaly. Perinatal death occurs in more than 60% of cases and is usually associated with hydrops fetalis, the presence of other malformations, or both. Even in the absence of extracardiac malformations, investigation for 22q11 deletion in cases of conotruncal cardiac abnormalities is recommended.

Prenatal diagnosis of familial absent pulmonary valve syndrome: case report and review of the literature

We report on a case of absent pulmonary valve syndrome in a woman with a history of one healthy child and one child with tetralogy of Fallot with absent pulmonary valve. The diagnosis was missed at the first ultrasound examination performed at 13 + 5 weeks of gestation and correctly diagnosed at 21 + 5 weeks. Re-evaluation of the ultrasound examination recorded at 13 + 5 weeks exhibited severe insufficiency of the pulmonary valve at this time. However, neither dilatation of the right and left pulmonary arteries nor asymmetry of the ventricles were present at that time. The pregnancy was terminated at 22 + 1 weeks of gestation when autopsy confirmed the diagnosis of absent pulmonary valve syndrome. Karyotyping of the fetus after termination of pregnancy revealed normal chromosomes. Echocardiography of the parents and the healthy sibling revealed normal results.

Autosomal recessive tetralogy of Fallot, unusual facies, communicating hydrocephalus, and delayed language development: a new syndrome?

We report a pattern of malformation affecting five of seven siblings born to unaffected Afghani parents who are first cousins. Their first two children died during infancy of cyanotic congenital heart defects. Two living male siblings have tetralogy of Fallot, developmental delay principally affecting language skills, and short palpebral fissures or midfacial hypoplasia. Another male has communicating hydrocephalus and hypertelorism. The striking number of siblings with tetralogy of Fallot, or another cyanotic congenital heart defect, and the parental consanguinity, suggests autosomal recessive inheritance in this family. While several other families have been identified with apparent recessive inheritance of tetralogy of Fallot, the associated malformations in our family suggest a unique, and previously unreported, malformation pattern.

Type III tracheal agenesis with familial tetralogy of Fallot and absent pulmonary valve syndrome

We describe a female infant born at 33 weeks gestation diagnosed postnatally with a previously unreported phenotype consisting of Type III tracheal agenesis plus tetralogy of Fallot with absent pulmonary valve. She was delivered to a mother who had the same congenital heart malformation, but no detectable tracheal abnormality. We discuss possible etiologies of these malformations.

Tetralogy of Fallot in three siblings: a familial study and review of the literature

We report a family in which three out of four siblings had tetralogy of Fallot (TOF). The family history showed TOF in the daughter of a maternal cousin, while no other congenital heart diseases were discovered. Although no teratogenic environmental agent was discovered, the absence of parental consanguinity and the presence of another affected relative suggest multifactorial inheritance. Autosomal recessive inheritance cannot be ruled out.

The inheritance of conotruncal malformations: a review and report of two siblings with tetralogy of Fallot with pulmonary atresia

Congenital heart defects (CHD) are a group of structural abnormalities that in humans have a combined incidence of approximately 1%. It is estimated that 4-5% of CHD are associated with chromosome abnormalities, 1-2% are associated with single gene syndromes, 1-2% are due to known teratogens, with the rest presumably determined multifactorially. We report on a brother and sister with tetralogy of Fallot with pulmonary atresia, and review the inheritance of familial conotruncal anomalies. We feel the small number of family clusters and the rare instances of consanguinity in non-syndromal conotruncal defects are consistent with multifactorial determination. While it is prudent in counseling families with 2 or more individuals with conotruncal CHD to raise the possibility of single gene inheritance, we believe that current empiric recurrence risk estimates most accurately reflect their risks.

Tetralogy of Fallot in three sibs

We report on three sibs (2 boys, one girl) with tetralogy of Fallot from non-consanguineous parents. The first child died during corrective surgery in 1972 from irreversible right ventricular failure. Corrective surgery was successful in the 2nd son and the daughter. The occurrence of tetralogy of Fallot in 3 sibs suggests a recessive gene.

Atrial septal defect, ventricular septal defect, and coarctation of the aorta in sibs: an autosomal recessive disorder?

We report on two sisters with secundum atrial septal defect, perimembranous ventricular septal defect, and coarctation of the aorta. Identical anatomical malformations were verified by echocardiography and at operation. No other affected relatives were identified. We suggest that this is a specific, possibly recessively inherited type of complex cardiac malformation.