Indonesian study links maternal FUT2 genotype with milk oligosaccharide levels

Human milk oligosaccharide composition is influenced by maternal fucosyltransferase genes, including FUT2. In this cross-sectional study, researchers analyzed milk samples from 120 healthy Indonesian mothers who were exclusively breastfeeding when their infants were 2–5 weeks old. They measured oligosaccharides using chromatography and sequenced the FUT2 coding region. Receiver operating characteristic analysis was used to estimate a 2′-fucosyllactose (2′FL) threshold against FUT2 genotype.

The reported proportion of secretor mothers was 65.8%, and secretor genotype was significantly associated with phenotype (p<0.001). The authors identified a novel FUT2 variant, c.851C>G, and reported a 2′FL threshold of 425.9 mg/L, with 98.7% sensitivity and 100% specificity in this sample. They noted that the proposed threshold differs from commonly used 25–50 mg/L cut-offs. The study was limited to a single population and one early lactation sampling period; the authors said the threshold requires evaluation against clinical outcomes and in longitudinal studies. It does not establish effects on infant health or support clinical use of the cut-off.