H Mel et al. J Pediatr 2022; 243: 53-60. Clinical and Genetic Etiologies of Neonatal Unconjugated Hyperbilirubinemia in the China Neonatal Genomes Project
Methods: The researchers used targeted panel sequencing data on 2742 genes including known unconjugated hyperbilirubinemia genes in 1412 neonates (in China). Exclusion criteria included gestational age <35 weeks and congenital malformations. 37% had severe unconjugated hyperbilirubinemia (reaching threshold recommended for exchange transfusion)
Findings:
- 45 (3%) of the cohort had genetic findings related to their unconjugated hyperbilirubinemia. 26 had variants associated with G6PD deficiency and eight had variants in UGT1A1 (which can cause Gilbert syndrome or Crigler-Najjar syndrome)
- 11 of 45 of genetic findings were due to more obscure causes including to RBC membrane defects, n=5 (ANK1, SPTB) and due to metabolic/biochemical disorders (GCDH, MMACHC, MUT, DUOX2, DUOXA2, MOCS1)
- Known clinical causes of hyperbilirubinemia were identified for 68% of patients. The most common clinical cause of unconjugated hyperbilirubinemia group was infection (15%). Other clinical causes included breastfeeding (n=154, 11%), extravascular hemorrhage (147, 10%), hemolytic disease (104, 7%) and inadequate feeding (82, 6%)
My take: About 3% of infants in this cohort had underlying genetic causes contributing to their jaundice; three-fourths of those with a genetic condition had either a variant of G6PD or UGT1A1
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