The Drosophila model has proven especially useful for studying the molecular pathogenesis of HRD: genetic tests of epistasis have led to the identification of spastin (itself linked to hereditary spastic paraplegia) as a TBCE partner in microtubule regulation (Jin et al., 2009), providing translational scientists with new insights into TBCE's mechanism of action. This evidence concerns the gene TBCE and hypoparathyroidism-retardation-dysmorphism syndrome.