Case report of three brothers with dystrophia myotonica or myotonia atrophica presenting some interesting aspects. On genetical field the authors note the coexistence of a disembrioplastic blastoma factor and homocronism. Likewise, authors note the constancy of the crystalline alterations, besides that there is no sterility as pointed by the clinical descriptions; the histopathological findings were inespecific but of a wide diagnostic value. The authors make some therapeutics remarks, specially about the use of ACTH and desoxycorticosteroids, associated with vitamins and hepatic extracts. The good indication of this therapeutic is, clinically and histopathologically, confirmed by the demonstration of muscular regeneration, finding of practic and theoretic interest.