IT HAS been pointed out by investigators that progressive infantile muscular atrophy as first described by Werdnig and Hoffmann has distinct hereditary-familial tendencies. Up to the time of a report by Brandt,2 200 cases occurring in 120 families had been reported. Review of the role of heredity in disease3 reveals that the same developmental anomaly can occur in more than one child of a family and often in several generations. In anomalies in general, the same malformation may occur in both identical twins, but it is unusual for fraternal twins to be affected by the same malformation.1 Also, mechanisms which are dependent on heredity in congenital defects are apparently dependent on recessive rather than dominant sex characteristics.
The relationship of infantile progressive muscular atrophy to that of Oppenheim's disease, or amyotonia congenita, is not disputed by most authorities. The fact that these conditions may be closely related