[Genetic etiology of newborn deaths]

Objective: To explore the genetic etiologies of newborn deaths. Methods: A total of 98 newborns who were recruited to the Neonatal Genome Project of the Children's Hospital of Fudan University and died in the hospital from January 2018 to August 2020 were enrolled in this study. The genetic information and the interventions based on the genetic findings were retrospectively analyzed. T-test, Mann-Whitney U test, Chi square test and Fisher's exact probability test were used to compare the demographic features and clinical characteristics between the patients with or without a genetic finding. Results: Among 98 newborns (55 males and 43 females), there were 63 preterm and 35 term infants, with a gestational age of (33±5) weeks, a birth weight of (2 107±975) g and the age at death of 12 (2,34) days. Sixteen (16%)patients were identified with genetic variants, including 11 with single nucleotide variants, 4 with copy number variants and 1 with both single nucleotide variant and copy number variant. The detected single nucleotide variants were spanning 12 genes, among which 3 were multiple disorders-related, 2 metabolic disorder-related, 2 hematological disorder-related, 2 respiratory disorder-related, 2 cardiovascular disorder-related and 1 skeletal disorder-related. The patients with a positive genetic finding had significant differences in the birth weight ((2 605±940) vs. (2 009±957) g, t=2.283, P=0.025), the gestational age ((36±5) vs. (33±5) weeks, t=2.131, P=0.036), the age at death ((37 (5, 69) vs. 11 (2, 29) days, Ζ=-2.245, P=0.025) and the history of asphyxia at birth (1/16 vs. 46% (38/82), P=0.002)when compared to those without a genetic finding. In addition, the genetic etiology rates of patients who were born term or with a birth weight ≥ 2 000 g were significantly higher than those who were born preterm (29% (10/35) vs. 10% (6/63), P=0.022) or with a birth weight<2 000 g (25% (13/51) vs. 7% (3/46), χ²=5.016,P=0.025), respectively. Six cases were medically actionable based on the genetic findings and the treatments included special diet, applying specific medicine, hematopoietic stem cell transplantation and lung transplantation. Conclusions: Genetic etiologies are not rare in newborn deaths and mainly associated with metabolic disorder, multi-system disorders, hematological disorder, respiratory disorder, cardiovascular disorder and skeletal disorder. Some findings are medically actionable, based on which the specific treatments could be scheduled timely. A genetic etiology should be investigated in newborn deaths especially in those who are term birth or with a birth weight ≥2 000 g or without a history of asphyxia at birth.