Despite therapeutic advances over the past decades, pulmonary arterial hypertension (PAH) and related pulmonary vascular diseases continue to cause significant morbidity and mortality in neonates, infants, and children. Unfortunately, an adequate understanding of underlying biology is lacking. There has been a growing interest in the role that genetic factors influence pulmonary vascular disease, with the hope that genetic information may aid in identifying disease etiologies, guide therapeutic decisions, and ultimately identify novel therapeutic targets. In fact, current data suggest that genetic factors contribute to ~42% of pediatric-onset PH compared to ~12.5% of adult-onset PAH. We report a case in which the knowledge that biallelic ATP13A3 mutations are associated with malignant progression of PAH in young childhood, led us to alter our traditional treatment plan for a 21-month-old PAH patient. In this case, we elected to perform a historically high-risk Potts shunt before expected rapid deterioration. Short-term follow-up is encouraging, and the patient remains the only known surviving pediatric PAH patient with an associated biallelic ATP13A3 mutation in the literature. We speculate that an increased use of comprehensive genetic testing can aid in identifying the underlying pathobiology and the expected natural history, and guide treatment plans among PAH patients.

Background: Neonates with congenital heart disease are more likely to be small for gestational age. Few studies have investigated the effect of birth weight Z-score on outcomes after congenital heart surgery. Methods: Patients from the Society of Thoracic Surgeons Congenital Heart Surgery Database (2010 to 2016) undergoing cardiac surgery at a corrected gestational age ≤ 44 weeks were included, and classified as severely (birth weight Z-score -4 to -2), moderately (Z-score between -2 and -1) and mildly growth restricted (Z-score -1.0 to -0.5) and compared to a reference (Z-score 0 to 0.5). Multivariable logistic regression clustering on center was used to evaluate the association of birth weight Z-score with operative mortality, postoperative complications and length of stay, adjusting for other patient characteristics. Interaction between Z-score for birth weight and gestational age was assessed. Results: In 25,244 patients, operative mortality was 8.6% and major complications occurred in 19.4%. Compared to the reference group with no growth restriction, the adjusted odds (AOR) of mortality was increased in infants with severe (AOR 2.4, CI 2.0-3.0), moderate (AOR 1.7, CI 1.4-2.0) and mild growth restriction (AOR 1.4, CI 1.2-1.6). The AOR for major postoperative complications was increased for infants with severe (AOR 1.4, CI 1.2-1.7) and moderate growth restriction (AOR 1.2, CI 1.1-1.4), but not in mildly growth restricted infants (AOR 1.0, CI 0.9-1.2). Length of stay was prolonged for all growth restricted cohorts (adjusted Hazard Ratio<1, p<0.05 for all). There was significant interaction between birth weight Z-score and gestational age (p=0.007) with the strongest association between birth weight Z-score and operative mortality in early-term (gestational age 37-38 weeks), followed by full-term (>38 weeks) and then preterm infants (<37 weeks). Conclusions: Even birth weight Z-scores that are slightly below average are independent risk factors for mortality and morbidity in neonates undergoing cardiac surgery. The strongest association between poor fetal growth and operative mortality exists in early-term neonates. These novel findings may account for some of the previously unexplained variation in cardiac surgical outcomes.

Objective

We hypothesized that infants with fetal growth restrictions have increased mortality and morbidity after congenital heart disease surgery.

Methods

The study included patients in The Society of Thoracic Surgeons Congenital Heart Surgery Database (2010-2016) who underwent cardiac surgery at a corrected gestational age of ≤44 weeks. Patients were classified as severely (birth weight Z-score -4 to -2), moderately (Z-score -2 to -1), and mildly growth restricted (Z-score -1.0 to -0.5) and compared with a reference population (Z-score 0-0.5). Multivariable logistic regression clustering on center was used to evaluate the association of birth weight Z-score with operative mortality and postoperative complications and its interaction with gestational age was assessed.

Results

In 25,244 patients, operative mortality was 8.6% and major complications occurred in 19.4%. Compared with the reference group, the adjusted odds ratio (AOR) of mortality was increased in infants with severe (AOR, 2.4; 95% confidence interval [CI], 2.0-3.0), moderate (AOR, 1.7; 95% CI, 1.4-2.0), and mild growth restriction (AOR, 1.4; 95% CI, 1.2-1.6). The AOR for major postoperative complications was increased for severe (AOR, 1.4; 95% CI, 1.2-1.7) and moderate growth restriction (AOR, 1.2; 95% CI, 1.1-1.4). There was significant interaction between birth weight Z-score and gestational age (P = .007).

Conclusions

Even birth weight Z-scores slightly below average are independent risk factors for mortality and morbidity in infants who undergo cardiac surgery. The strongest association between poor fetal growth and operative mortality exists in early-term infants. These novel findings might account for some of the previously unexplained variation in cardiac surgical outcomes.

Down's syndrome results from full or partial trisomy of chromosome 21. However, the consequences of the underlying gene-dosage imbalance on adult tissues remain poorly understood. Here we show that in Ts65Dn mice, which are trisomic for 132 genes homologous to genes on human chromosome 21, triplication of Usp16 reduces the self-renewal of haematopoietic stem cells and the expansion of mammary epithelial cells, neural progenitors and fibroblasts. In addition, Usp16 is associated with decreased ubiquitination of Cdkn2a and accelerated senescence in Ts65Dn fibroblasts. Usp16 can remove ubiquitin from histone H2A on lysine 119, a critical mark for the maintenance of multiple somatic tissues. Downregulation of Usp16, either by mutation of a single normal Usp16 allele or by short interfering RNAs, largely rescues all of these defects. Furthermore, in human tissues overexpression of USP16 reduces the expansion of normal fibroblasts and postnatal neural progenitors, whereas downregulation of USP16 partially rescues the proliferation defects of Down's syndrome fibroblasts. Taken together, these results suggest that USP16 has an important role in antagonizing the self-renewal and/or senescence pathways in Down's syndrome and could serve as an attractive target to ameliorate some of the associated pathologies.