Analysis of genetic etiology of 234 deaths in the pediatric intensive care unit with suspected genetic diseases

Abstract

Objective: To explore the genetic etiology of pediatric intensive care unit (PICU) mortality cases and summarize their clinical characteristics. Methods: This was a retrospective cohort study. The study population consisted of 234 children who died within 7 d after admitted to the PICU of Children's Hospital of Fudan University from January 2017 to December 2021. The clinical diagnoses, laboratory test results, and genetic testing results were collected. These patients were divided into the pathogenic gene variation positive (PGVP) group and the pathogenic gene variation negative (PGVN) group according to the results of genetic testing. The Mann-Whitney U test and Pearson's chi-square test or Fisher's exact probability method were used to compare the clinical characteristics between the groups. Results: A total of 234 cases were enrolled, including 139 (59.4%) males and 95 (40.6%) females. The age at death was 1.0 (0.4, 3.7) years old and the length of PICU stay was 16 (6, 33) days. There were 62 cases (26.5%) PGVP, and the mutated pathogenic genes included immune genes (23 cases (37.1%)), metabolic genes (11 cases (17.7%)), neuromuscular genes (11 cases (17.7%)), cardiovascular genes (4 cases (6.5%)), and genes of other systems (13 cases (21.0%)). The age at death in PGVP cases was significantly lower than in PGVN cases (0.6 (0.3, 1.4) vs. 1.3(0.5, 4.3) years old, Z=3.85, P<0.001). Compared with the PGVN group, the PGVP group had a higher incidence of family history and chronic complex conditions (CCC) than the PGVN group (6.5% (4/62) vs. 0.6% (1/172) and 93.5% (58/62) vs. 76.2% (131/172), χ2=8.87, P=0.018 and 0.003, respectively). Children in the PGVP group were admitted with higher incidence of severe infection, decreased consciousness or coma, moderate-to-severe anemia, thrombocytopenia, protracted diarrhea, and abnormalities in muscle strength or tone than those in the PGVN group (74.2%(46/62) vs. 45.9%(79/172), 50.0%(31/62) vs. 35.5%(61/172), 32.3%(20/62) vs. 18.0%(31/172), 21.0%(13/62) vs. 10.5%(18/172), 25.8%(16/62) vs. 4.1%(7/172), 16.1%(10/62) vs. 5.2%(9/172), χ2=14.63, 4.04, 5.41, 4.37, 24.30, 7.25, all P<0.05). Pathogenic genes that occurred more than twice included IL2RG (5 cases), SMN1 (4 cases), and SH2D1A (3 cases, including 2 single gene varients and 1 copy number varient). Conclusions: Among the deceased cases in the PICU, the main genetic causes are immune-related, metabolic, and neuromuscular genetic disorders. Critically ill children with a family history, CCC, and early features such as severe infections, decreased consciousness or coma, moderate to severe anemia, thrombocytopenia, protracted diarrhea, or abnormalities in muscle strength or tone should be closely monitored and undergo early genetic testing.