MYF5 and muscular dystrophy: Indeed, two groups previously compared the two distinct conditional fukutin knock-out (cKO) mice; the first, a myofibre-selective fukutin-conditional knock-out (using the muscle creatine kinase promoter to drive the deletion), which showed a mild muscular dystrophy whilst the second, deleted fukutin in muscle precursor cells using the Myf5 promoter.