Compounds of formula: where: - R1 and R2 are each independently a hydrogen atom or halogen atom, in particular a chlorine atom, or trifluoromethyl group, alkyl group having 1 to 5 carbon atoms, or O-alkyl group having 1 to 5 carbon atoms; - W is a sulfur atom or CH 2 -CH 2 or CH=CH sequence, or a CH group attached to Y to form a bridge (CH 2) 2; - Y is a nitrogen atom or carbon atom on the understanding that when W and Y are attached by a (CH 2) 2 chain, Y is a carbon atom; - X1 is a hydrogen atom or alkyl group having 1 to 4 carbon atoms or else it is attached to R3 to form a piperidine group. - X2 is defined as follows: when Y is a nitrogen atom or carbon atom attached to W to form a (CH 2) 2 bridge, X2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or when Y is a carbon atom not attached to W to form a (CH 2) 2 bridge, X2 forms a covalent bond between the carbon to which it is attached and Y, so that Y-CX1X2 represents C=CX1, - a equals 0 or 1; - Y1 and Y2 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; - X3 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or X3 is attached to R3 to form a piperidine group - R3 and R4 are defined as follows: ∘ R3 is an alkyl group having 1 to 5 carbon atoms, or else R3 is attached to X1 to form a piperidine group, or else R3 is attached to X3 to form a piperidine group; ∘ R4 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; ∘ or else R3 is attached to R4 to form a piperidine, pyrrolidine or piperazine group the nitrogen atom of which is optionally substituted by an alkyl group having 1 to 4 carbon atoms or by a - b OH group where b equals 1, 2 or 3, optionally in the form of pharmaceutically acceptable salts, solvates or hydrates for use thereof in the treatment or prevention of pathologies corresponding to muscular degeneration of skeletal muscles selected from among muscular myopathies of genetic origin. - R1 and R2 are each independently a hydrogen atom or halogen atom, in particular a chlorine atom, or trifluoromethyl group, alkyl group having 1 to 5 carbon atoms, or O-alkyl group having 1 to 5 carbon atoms; - W is a sulfur atom or CH 2 -CH 2 or CH=CH sequence, or a CH group attached to Y to form a bridge (CH 2) 2; - Y is a nitrogen atom or carbon atom on the understanding that when W and Y are attached by a (CH 2) 2 chain, Y is a carbon atom; - X1 is a hydrogen atom or alkyl group having 1 to 4 carbon atoms or else it is attached to R3 to form a piperidine group. - X2 is defined as follows: when Y is a nitrogen atom or carbon atom attached to W to form a (CH 2) 2 bridge, X2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or when Y is a carbon atom not attached to W to form a (CH 2) 2 bridge, X2 forms a covalent bond between the carbon to which it is attached and Y, so that Y-CX1X2 represents C=CX1, when Y is a nitrogen atom or carbon atom attached to W to form a (CH 2) 2 bridge, X2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or when Y is a carbon atom not attached to W to form a (CH 2) 2 bridge, X2 forms a covalent bond between the carbon to which it is attached and Y, so that Y-CX1X2 represents C=CX1, - a equals 0 or 1; - Y1 and Y2 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; - X3 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or X3 is attached to R3 to form a piperidine group - R3 and R4 are defined as follows: ∘ R3 is an alkyl group having 1 to 5 carbon atoms, or else R3 is attached to X1 to form a piperidine group, or else R3 is attached to X3 to form a piperidine group; ∘ R4 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; ∘ or else R3 is attached to R4 to form a piperidine, pyrrolidine or piperazine group the nitrogen atom of which is optionally substituted by an alkyl group having 1 to 4 carbon atoms or by a - b OH group where b equals 1, 2 or 3, ∘ R3 is an alkyl group having 1 to 5 carbon atoms, or else R3 is attached to X1 to form a piperidine group, or else R3 is attached to X3 to form a piperidine group; ∘ R4 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; ∘ or else R3 is attached to R4 to form a piperidine, pyrrolidine or piperazine group the nitrogen atom of which is optionally substituted by an alkyl group having 1 to 4 carbon atoms or by a - b OH group where b equals 1, 2 or 3,