Mdr3 gene mutation in preterm infants with parenteral nutrition‐associated cholestasis

To investigate the relationship of multidrug resistance 3 (Mdr3) gene mutation and parenteral nutrition‐associated cholestasis (PNAC) in preterm infants. Preterm infants who had received total parenteral nutrition for at least 14 days were enrolled: 76 preterm infants in the PNAC group and 80 preterm infants in the non‐PNAC group. Genomic DNA was extracted from white blood cells. Twenty‐eight exons of the Mdr3 gene were amplified by polymerase chain reaction. PNAC infants of 1 month corrected age with the Mdr3 gene mutation and abnormal liver biochemistry were selected for the experimental liver biopsy group. Five normal adult living liver transplantation donors were enrolled in a normal donor group. The Mdr3 missense mutations c.1031G>A, c.3347G>A, and c.485T>A, and the Mdr3 frameshift mutation c.2793_2794insA were found in the PNAC group. The allele frequency and genotype frequency of c.1031G>A, c.3347G>A, and c.485T>A in the Mdr3 gene in the PNAC group were significantly higher than those in non‐PNAC group (p < 0.05). The rate of Mdr3 gene mutations c.1031G>A, c.485T>A, c.3347G>A, and c.2793_2794insA in the PNAC group was higher than in the non‐PNAC group (21.05% vs. 1.25%, respectively, χ (2) = 15.747, p < 0.05). Mdr3 gene mutations c.2793_2794insA, c.1031G>A, c.3347G>A, and c.485T>A may be the genetic cause of PNAC.