NR2F2 is one the most conserved genes in the human genome and is intolerant to protein-truncating variants.14 To exclude the possibility that these NR2F2 mutations may be a chance finding, we performed Fisher’s exact tests (two-tailed) on the frequency of protein-truncating mutations found in the case subjects and compared this to rare missense mutations from 6,489 control European American and African American cohorts in the NHLBI-ESP project. A rare variant is defined as a variant with an allelic frequency of <1% in publically available databases. We found no protein-truncating mutations present in the control populations. We found a highly significant enrichment for the NR2F2 protein-truncating mutations identified in the three 46,XX DSD-affected case subjects compared to the absence of protein-truncating mutations in the control cohort (Fisher’s exact test, two-tailed p = 1.1 × 10−6). Even if we consider the five missense mutations present in the control population, the finding of three frameshift mutations in the 46,XX DSD cohort is still highly significant (p = 6 × 10−5). The genetic evidence in favor of causality is more compelling when one considers that the protein-truncating mutations were specifically identified only in the three children presenting with CHD and 46,XX DSD (p = 2.44 × 10−8).