SLC9A3 and congenital secretory chloride diarrhea 1: Second, SLC26A3 plays, together with SLC9A3, a major role in the reabsorption of NaCl and fluid in the efferent ducts of the testis, reflected by the CLD-associated low seminal plasma pH and a high Cl− content, in addition to the luminal accumulation of fluid and infertility in both CLD men and SLC9A3 (MIM: 182307) knockout mice8,54.