Triple-A syndrome: a wide spectrum of adrenal dysfunction

Abstract

Triple-A or Allgrove syndrome is an autosomal recessive disorder due to mutations in the AAAS gene, which encodes a nucleoporin named ALADIN. It is characterized by a classical clinical triad: alacrima, achalasia and adrenal insufficiency, the canonic symptoms that are associated with progressive peripheral neuropathy. Only a few cohorts have been reported. The objective of the present study was to characterize the various spectra of adrenal function in Triple-A patients. A retrospective clinical and biological monitoring of 14 patients (10 families) was done in a single multidisciplinary French center. All had AAAS gene sequenced and adrenal function evaluation. Nine different AAAS mutations were found, including one new mutation: c.755G>C, p.(Trp252Ser). Regarding adrenal function, defects of the zona fasciculata and reticularis were demonstrated by increased basal ACTH levels and low DHEAS levels in all cases regardless of the degree of glucocorticoid deficiency. In contrast, mineralocorticoid function was always conserved: i.e., normal plasma renin level associated with normal aldosterone level. The main prognostic feature was exacerbation of neuropathy and cognitive disorders. These data suggest that, in Triple-A patients, adrenal function can be deficient, insufficient or compensated. In our cohort after the first decade of life, there does not appear to be any degradation of adrenal function over time. However, patients with compensated adrenal function should be informed and educated to manage a glucocorticoid replacement therapy in case of stressful conditions, with no need for systematic long-term treatment.