To investigate the relationship between the early-life environment and GR gene (NR3C1) methylation status, which may take part in long-lasting neurodevelopmental impairment, we performed a longitudinal analysis of methylation ratios within the GR gene promoter 1F region using next-generation sequencing in preterm infants with CLD. This evidence concerns the gene NR3C1 and congenital secretory chloride diarrhea 1.