Autoimmune polyendocrine syndrome type 2 in children: a case report and literature review.

Background: Autoimmune polyendocrine syndrome (APS) is a clinical disorder characterized by the loss of immune tolerance, leading to dysfunction in multiple endocrine glands. According to the latest disease classification, APS is categorized into three main subtypes: APS-1, APS-2, and IPEX (Immune Dysregulation, Polyendocrinopathy, Enteropathy, X-linked) syndrome. APS-2 is defined by the presence of at least two autoimmune endocrine disorders, such as type 1 diabetes mellitus, autoimmune thyroiditis, or Addison's disease. APS-2 typically manifests later than APS-1, with onset most commonly occurring in early adulthood. However, pediatric cases involving a combination of autoimmune thyroid disease, type 1 diabetes mellitus, and myasthenia gravis, are extremely rare.

Case presentation: This article reported the case of a 3-year-old girl diagnosed with autoimmune polyendocrine syndrome type 2 (APS-2). The patient initially presented with hyperthyroidism and exophthalmos and was subsequently diagnosed with type 1 diabetes mellitus and myasthenia gravis. To our knowledge, this case represents the youngest reported patient of APS-2 at the time of diagnosis, as well as the shortest documented interval between the onset of autoimmune disorders affecting distinct endocrine glands.

Conclusions: Through a retrospective analysis, we comprehensively reviewed the phenotypic characteristics of APS-2 and explored its potential immune mechanisms. This article aims to provide clinicians with a valuable reference case to enhance early recognition and facilitate the implementation of targeted prevention and treatment strategies.