[Spinal muscular atrophy in young infants]

Two congenital anterior horn cell diseases may be responsible for neonatal muscular atrophy. The acute Werdnig-Hoffmann disease (SMA-I) has a progressive course, the anterior horn cell degeneration (AHCD) is non progressive in the postnatal period. In case of Werdnig-Hoffmann disease symptoms of hypotonia and muscle weakness may be present at birth, but become progressive during the first months of live. The full clinical picture of AHCD is present at birth. In the latter clinical symptoms of fetal hypokinesia may be noticed during intrauterine life. Histopathological muscle investigation reveals a more or less characteristic neurogenic pattern in Werdnig-Hoffmann disease, in AHCD neurogenic and myopathic changes are variable. Two examples of these diseases will be discussed.