MTNR1B and gestational diabetes: While a Korean study of GDM [27] with a smaller sample size (1399 cases and 2025 controls) previously reported both MTNR1B and CDKAL1 as GDM-associated loci, with CDKAL1 exhibiting the largest genetic effect, our study, along with the NIPT PLUS and BIGCS replication cohorts, indicates that MTNR1B plays a more substantial role in GDM susceptibility than CDKAL1 (Table 1).