Blood selenium in chronic spinal muscular atrophy

The spinal muscular atrophies (SMA) of childhood comprise the second most common fatal recessive disease after cystic fibrosis, yet the nature of the biochemical defect causing the anterior horn cell degeneration is totally unknown. Recent reports of a cluster of adult motor neurone disease cases from a high seleniferous area in South Dakota have prompted the study of blood selenium in children with SMA in Australia. Eight children with chronic SMA were tested, in addition to 9 obligate heterozygote carriers of the gene. Blood selenium levels of patients and carriers did not differ significantly from that observed in controls. The mammalian effects of selenium toxicity are discussed.