Pernicious Anemia in a Pediatric Patient With Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is an autosomal recessive disease caused by a monogenic pathogenic mutation in the autoimmune regulator (AIRE) gene. AIRE is a transcriptional regulatory gene expressed within thymic medullary cells, which play a critical role in developing central immune tolerance. APECED is classically associated with the triad of chronic mucocutaneous candidiasis, hypoparathyroidism, and adrenal insufficiency. We report a case of a pediatric patient with a known history of APECED who presented with symptomatic megaloblastic anemia and was found to have vitamin B12 deficiency secondary to the presence of antibodies to intrinsic factors. Interestingly, our patient did not have gastric parietal cell antibodies, which are present in 90% of pernicious anemia cases. Pernicious anemia itself is relatively rare and primarily manifests in the elderly population. There is limited literature involving pernicious anemia within the pediatric population, specifically within the subgroup that has APECED. Screening and early recognition of pernicious anemia in this relatively rare condition is crucial, as it has the potential to be life-threatening if left unaddressed.