A recent study in an Sts-deletion mouse has implicated dysregulated Wnt/β and Hippo signaling, and excessive reactive oxygen species production, in the abnormal skin phenotype observed in this model [50]; disruption to these pathways has previously been suggested to contribute towards cardiac disease risk [51,52] and they warrant further examination in individuals with XLI, in rodent models and in non-mammalian models such as zebrafish [53,54]. This evidence concerns the gene STS and heart disorder.