ACPA SC was also associated with emphysema (7.9 ± 8.6 U/ml, P = 3.89 × 10− 7) and CLD (6.8 ± 18.7 U/ml, P = 3.05 × 10− 5). This evidence concerns the gene PRTN3 and congenital secretory chloride diarrhea 1.