Lessons from prospective longitudinal follow-up of a French APECED cohort

APECED syndrome is a rare disease caused by biallelic mutations of the AIRE gene, usually presenting with the triad "hypoparathyroidism-adrenal failure-chronic mucocutaneous candidiasis (CMC)" and non-endocrine manifestations. The aim of this study was to determine the molecular profile of the AIRE gene, the prevalence of rare manifestations and to characterize immunological disturbances in a French cohort. A national, multicenter prospective observational study to collect genetic, clinical, biological and immunological data (NCT03751683). 25 patients (23 families) were enrolled. Eleven distinct AIRE variants were identified, two of which were not previously reported: an intronic variant, c.653-70G > A, and a c.1066del (p.Arg356GlyfsX22) variant (exon 9). The most common was the Finnish variant c.769C > T (16 alleles), followed by the variant c.967_979del13 (15 alleles), which seemed associated with a less severe phenotype. 17/25 patients were homozygote. The median number of clinical manifestations was seven; 19/25 patients presented with the hypoparathyroidism-adrenal failure-CMC triad, 8/13 showed pulmonary involvement, 20/25 had ectodermal dystrophy, 8/25 had malabsorption, and 6/23 had asplenia. Fifteen out of 19 patients had NK cell lymphopenia with an increase in CD4+ and CD8+ T lymphocytes and an age-dependent alteration of B lymphocyte homeostasis compared with matched controls (p