Spinal muscular atrophy (SMA) is a phenotypically heterogeneous disease. Although the life expectancy and motor capability is significantly reduced in most patients, SMA types III and IV patients live to adulthood. In some cases, the association with a higher number of copies of the SMN2 gene and other protective factors are responsible for minimal motor impairment only. However, precise data on the prevalence of this disease in adult patients remain unknown. In the adult age, in addition to the classical 5q13 form of SMA, there are other rare genetic forms of late onset SMA with dominant disability in the lower limbs, which must be distinguished because of different clinical and therapeutic approaches. Since the development of SMA therapy, there has been a need for a clinical evaluation of therapeutic response and a definition of multidisciplinary care standards that have some specifics in adult SMA patients.