They are ubiquitous and have been found abnormally expressed in several tumors.5 In muscle cells, miR-221/222 have been shown to target p27 (Cdkn1b),4 β1-syntrophin (Sntb1)6 and, more recently, MyoD transcription factor.7 In addition, an increase in miR-221/222 expression was described in muscles from mdx dystrophic mice and in muscle tissues from several human primary muscle disorders,8, 9 linking these miRNAs to muscle disease. Here, CDKN1B is linked to muscular disease.