We describe a large New England kindred bearing an autosomal dominant syndrome of neurogenic amyotrophy with variable expression. Features include congenital absence of muscles, progressive scapuloperoneal atrophy, laryngeal palsy, and progressive distal weakness and atrophy. The pattern of expression and progression varies in different branches of the family. Males are more severely affected than females. Disease expression is more severe and progressive in succeeding (third and fourth) generations. This striking increase in severity and progressivity in succeeding generations may have genetic implications. The syndrome most resembles the Stark-Kaeser chronic scapuloperoneal amyotrophy, but is considered a distinct entity.