[Clinical and instrumental study of familial congenital myasthenia].

Congenital familial myasthenia occurred in two male brothers, born from non affected mother. The diagnosis was based on anamnestic and clinical data, on electromyographic features, and on the effect of specific therapy. The differential diagnosis and the classification of congenital familial myasthenia are discussed. This type of disease represent 1% of all cases of myasthenia, but--excluding the "transferred" myasthenia to the newborn by affected mother--the percentage raises to 3--4%. The possibility of identifying two distinct formes of familial myasthenia is emphasized, the first with "early onset" where the symptoms become evident before two years of age, the second "late onset" clinically evident later in life seems doubtful that the two forms of the disease might be due to the same underlying pathological condition.