Corticosteroid-binding globulin (SERPINA6) deficiency is an extremely rare hereditary disorder characterized by reduced corticosteroid-binding capacity with normal or low plasma corticosteroid-binding globulin concentration, and normal or low basal cortisol levels associated with hypo-/hypertension and muscle fatigue. We recently investigated a patient with severe muscle fatigue, normal blood pressure, and abnormal high saliva cortisol levels following a standardized stress test. This patient was found heterozygous for a de novo 367 asparagine-encoding variant of the corticosteroid-binding globulin gene, previously described as "transcortin Lyon". Both parents were homozygous for the ("wildtype") 367 aspartate-encoding allele. To the best of our knowledge, this case represents the first de novo mutation reported for corticosteroid-binding globulin deficiency, implicating a pathogenic role of variants of SERPINA6 in some cases of muscle fatigue.
Own publication on the subject:
C. Buss, U. Schuelter, J. Hesse, D. Moser, D. I. Phillips, D. Hellhammer, J. Meyer (2007): Haploinsufficiency of the SERPINA6 gene is associated with severe muscle fatigue: A de novo mutation in corticosteroid-binding globulin deficiency; J. Neural Transm. 114: 563-569.