Despite encouraging performance from CE-marked assays internationally and promising early US data using experimental point-of-care anti-treponemal IgM tests, no treponemal-IgM assay is currently FDA-cleared for CS diagnostics in the U.S. Consistent with this, routine IgM testing is not recommended by the CDC because of variable accuracy, limited clinical validation, and inconsistent correlation with disease stage (7). The gene discussed is CD40LG; the disease is Cowden syndrome 1.