To determine whether SMNT deletion may be associated with arthrogryposis, we tested DNA extracted from paraffin blocks for deletion of SMNT (exons 7 and 8). Analysis of the DNA showed an SMNT deletion in two of four infants with neurogenic arthrogryposis. In addition to loss of anterior horn cells, patients with SMNT deletion had degeneration of central sensory neurons in Clarke's column and the thalamus. Although one of the patients with no deletion also had cortical pathology, clinical and pathologic characteristics of the two patients without deletion were otherwise similar to the two patients with deletion. Arthrogryposis and degeneration of sensory neurons may be associated with deletion of SMNT.