Gilmartin et al. (1977) reported an inbred Mennonite kindred in which 5 sibships had children who succumbed to a neonatal radiculoneuropathy. One parent of each of the 5 sibships was a member of 1 sibship (i.e., the 5 ... Gilmartin et al. (1977) reported an inbred Mennonite kindred in which 5 sibships had children who succumbed to a neonatal radiculoneuropathy. One parent of each of the 5 sibships was a member of 1 sibship (i.e., the 5 sibships were related as first cousins). In addition, the other parents in 2 of the sibships were sibs and the other parents in the final 3 sibships were sibs. Death of affected infants occurred at an early age. The clinical picture was that of the 'floppy infant' and superficially suggested Werdnig-Hoffmann disease (253300). However, polyhydramnios (due to fetal swallowing deficiency), distal muscle weakness, areflexia, diaphragmatic involvement, opisthotonic posturing, autonomic instability, and chronic diarrhea were features not usually found in infantile spinal muscular atrophy.