Prenatal diagnosis and outcome of absent pulmonary valve syndrome: contemporary single-center experience and review of the literature

OBJECTIVE

To review the anomaly spectrum of prenatally detected absent pulmonary valve syndrome (APVS) and the outcome after diagnosis. Previous fetal studies reported survival rates of ≤ 25% for patients with intended postnatal care.

METHODS

Clinical data and echocardiograms of 12 cases with a fetal diagnosis of APVS between 2000 and 2010 were analyzed in this retrospective single-center study. Collected parameters included: gestational age at referral, associated fetal abnormalities, cardiothoracic ratio, maximum diameters of pulmonary annulus and main and branch pulmonary arteries, ventricular dimensions and function as well as ventricular Doppler flows. Karyotyping included fluorescence in-situ hybridization (FISH) analysis for microdeletion 22q11.2.

RESULTS

Median gestational age at diagnosis was 24 weeks. Three subtypes of APVS were observed: (1) with tetralogy of Fallot (TOF) and no arterial duct (n = 10; 83%); (2) isolated, with a large arterial duct (n = 1; 8%); and (3) with tricuspid atresia, right ventricular dysplasia and a restricted duct (n = 1; 8%). The cardiothoracic ratio and pulmonary artery dimensions were increased in all cases. The karyotype was abnormal in 70% of fetuses with TOF and their mortality rate was significantly higher due to pregnancy termination (n = 3) or perinatal demise (n = 2) (hazard ratio, 5; 95% CI, 0.87-28.9; P = 0.015). Of seven live births with active postnatal care, six children (86%) were alive without residual respiratory symptoms at a median follow-up of 4.7 (range, 2.1-10.6) years.

CONCLUSION

Outcome after fetal diagnosis of APVS was significantly better in this study compared with those of previous fetal series, with a low mortality rate for actively managed patients.

Genome-wide RNAi identifies p53-dependent and -independent regulators of germ cell apoptosis in C. elegans

We used genome-wide RNA interference (RNAi) to identify genes that affect apoptosis in the C. elegans germ line. RNAi-mediated knockdown of 21 genes caused a moderate to strong increase in germ cell death. Genetic epistasis studies with these RNAi candidates showed that a large subset (16/21) requires p53 to activate germ cell apoptosis. Apoptosis following knockdown of the genes in the p53-dependent class also depended on a functional DNA damage response pathway, suggesting that these genes might function in DNA repair or to maintain genome integrity. As apoptotic pathways are conserved, orthologues of the worm germline apoptosis genes presented here could be involved in the maintenance of genomic stability, p53 activation, and fertility in mammals.