X-linked infantile spinal muscular atrophy
F. Greenberg, K. R. Fenolio, J. F. Hejtmancik, D. Armstrong, J. K. Willis, E. Shapira, H. W. Huntington and R. L. Haun
Institute of Molecular Genetics, Baylor College of Medicine, Houston, TX.
Four male infants from three sibships in an extended family were noted to
have hypotonia, areflexia, and congenital joint contractures. The findings
of electromyography and muscle histology were consistent with infantile
spinal muscular atrophy (SMA). Pedigree analysis suggests that this
disorder represents an X-linked, recessive form of SMA. Findings in similar
kindreds may explain the previously reported increased male-female ratio in
infantile SMA.