It crosses the second most common fragile site (FRA16D) in the human genome.Somatic sequence variants in WWOX were found inmany types of neoplasia and WWOX is recognized asan important tumor suppressor gene.1 More recently, germline pathogenic variantsin WWOX were implicated in constitutionaldiseases and three different WWOX-related phenotypes were described: disorder of sexdifferentiation (DSD), spinocerebellar ataxia (SCA), and epileptic encephalopathy. The gene discussed is WWOX; the disease is disorder of sexual differentiation.