Several deleterious mutations in the XRCC4 gene have been reported in humans (see de Villartay, 2015 for review), most of which are associated with microcephalic primordial dwarfism (MPD), gonadal failure, early-onset metabolic syndrome, and cardiomyopathies. The gene discussed is XRCC4; the disease is microcephalic primordial dwarfism.