Median MBL levels were similar in cases and controls (0.7 (IQR 0.2–1.6) vs. 0.7 (IQR 0.1–1.7) μg/ml, respectively, p = 0.9) as was the frequency of moderate and severe MBL deficiency (46 vs. 43%, respectively, p = 0.7 and 19 vs. 23%, respectively, p = 0.5). Here, MBL2 is linked to hyperinsulinemic hypoglycemia, familial, 4.