During the same time period, 189,857 infants born in Indiana underwent NBS for CF and had no identified CFTR variants, i.e., infants with an IRT not in the top 4% for the day, or in the top 4% for the day but with no CFTR variants identified, and were not diagnosed with CF through other means, e.g., meconium ileus. Here, CFTR is linked to intestinal obstruction in the newborn due to guanylate cyclase 2C deficiency.