SPEG is a protein highly expressed in striated muscle cells and cardiomyocytes, which play an important role in the differentiation of vascular smooth muscle cell in early life.9, 10, 11, 12 Recessive SPEG (Striated muscle enriched protein kinase) mutations were first identified in CNM patients by Agrawal in 2014.13 To date, SPEG mutations have been identified in eight CNM and 1 CM patients.13, 14, 15, 16, 17 Most of these patients had severe hypotonia and muscle weakness. This evidence concerns the gene SPEG and cutaneous mastocytosis.