FKTN and Menkes disease: As fukutin is expressed in many tissues including heart, brain, skeletal, muscle, and pancreas, the disease phenotypes caused by FKTN-mutations vary from dilated cardiomyopathy (DCM) and/or muscular dystrophy (MD)/dystroglycanopathy to severe congenital MD with brain malformation, intellectual disability, and abnormal eye structure [7,13,14].