Causative genetic variants are reported in only 35–45% of 46,XY DSD patients4,5 and a handful of genes are diagnostic for 46,XY gonadal dysgenesis with extragonadal comorbidities (ranging from neurodevelopmental defects to heart, kidney and skeletal anomalies) e.g. ARX (MIM 300382), ATRX (MIM 300032) DHH (MIM 605423), SOX9 (MIM 608160) and WT1 (MIM 607102)6–10. This evidence concerns the gene ARX and disorder of sexual differentiation.