[Assessment of autoantibodies against 21-hydroxylase in the diagnosis of primary autoimmune adrenal insufficiency]

Primary adrenal insufficiency is manifested by a deficiency of adrenal cortex hormones and can lead to a life-threatening condition. Early diagnosis is key to patient survival. Auto-antibodies to one of the adrenal steroidogenesis enzymes, 21-hydroxylase, are an immunological marker of autoimmune adrenal insufficiency. On the one hand, the study of antibodies to 21-hydroxylase is a method that helps establish the etiology of the disease – the autoimmune genesis of adrenal gland damage. On the other hand, the determination of autoantibodies to 21-hydroxylase is the only prognostic factor of the risk of adrenal insufficiency, which makes it possible to prevent the development of acute adrenal crisis. The article provides a brief literature review on autoantibodies to 21-hydroxylase and the pathogenesis of autoimmune adrenal insufficiency, and a series of clinical cases that illustrates the significant role of autoantibodies to 21-hydroxylase in diagnosis of adrenal insufficiency.

[Clinical case report: history of diagnosis and clinical features of type autoimmune polyglandular syndrome 1]

Autoimmune polyglandular syndrome type 1 (APS-1) is a rare disease with autosomal recessive inheritance and it caused by mutations in the autoimmune regulator (AIRE) gene. This disease has clinical polymorphism that including besides endocrinopathies other organ-specific manifestations and that complicates to diagnose of this condition on time. However, most often APS-1 has a characteristic debut and a certain stage of clinical symptom manifestation. This article describes a case report of an 18-year-old patient with confirmed APS-1, in which the course of disease was erased over a long period of life and didnt meet of clinical criteria for the diagnosis in this syndrome. A high quality of life for such patients is possible with timely, individually selected replacement therapy with subsequent follow-up. It is important to remember the need for screening in risk groups for the formation of clinical forms of APS among the subjects presenting with a single endocrine pathology. The continuity of medical supervision by pediatric and adult endocrinological service physicians must be respected that can be traced on the example of the case from our practice.

Expanding the Phenotypic and Genotypic Landscape of Autoimmune Polyendocrine Syndrome Type 1

Context

Autoimmune polyendocrine syndrome type 1 (APS-1) is a rare monogenic autoimmune disease caused by mutations in the autoimmune regulator (AIRE) gene and characterized by chronic mucocutaneous candidiasis, hypoparathyroidism, and primary adrenal insufficiency. Comprehensive characterizations of large patient cohorts are rare.

Objective

To perform an extensive clinical, immunological, and genetic characterization of a large nationwide Russian APS-1 cohort.

Subjects and Methods

Clinical components were mapped by systematic investigations, sera were screened for autoantibodies associated with APS-1, and AIRE mutations were characterized by Sanger sequencing.

Results

We identified 112 patients with APS-1, which is, to the best of our knowledge, the largest cohort described to date. Careful phenotyping revealed several additional and uncommon phenotypes such as cerebellar ataxia with pseudotumor, ptosis, and retinitis pigmentosa. Neutralizing autoantibodies to interferon-ω were found in all patients except for one. The major Finnish mutation c.769C>T (p.R257*) was the most frequent and was present in 72% of the alleles. Altogether, 19 different mutations were found, of which 9 were unknown: c.38T>C (p.L13P), c.173C>T (p.A58V), c.280C>T (p.Q94*), c.554C>G (p.S185*), c.661A>T (p.K221*), c.821del (p.Gly274Afs*104), c.1195G>C (p.A399P), c.1302C>A (p.C434*), and c.1497del (p.A500Pfs*21).

Conclusions

The spectrum of phenotypes and AIRE mutation in APS-1 has been expanded. The Finnish major mutation is the most common mutation in Russia and is almost as common as in Finland. Assay of interferon antibodies is a robust screening tool for APS-1.

Dominant Mutations in the Autoimmune Regulator AIRE Are Associated with Common Organ-Specific Autoimmune Diseases

The autoimmune regulator (AIRE) gene is crucial for establishing central immunological tolerance and preventing autoimmunity. Mutations in AIRE cause a rare autosomal-recessive disease, autoimmune polyendocrine syndrome type 1 (APS-1), distinguished by multi-organ autoimmunity. We have identified multiple cases and families with mono-allelic mutations in the first plant homeodomain (PHD1) zinc finger of AIRE that followed dominant inheritance, typically characterized by later onset, milder phenotypes, and reduced penetrance compared to classical APS-1. These missense PHD1 mutations suppressed gene expression driven by wild-type AIRE in a dominant-negative manner, unlike CARD or truncated AIRE mutants that lacked such dominant capacity. Exome array analysis revealed that the PHD1 dominant mutants were found with relatively high frequency (>0.0008) in mixed populations. Our results provide insight into the molecular action of AIRE and demonstrate that disease-causing mutations in the AIRE locus are more common than previously appreciated and cause more variable autoimmune phenotypes.

[SPECIFIC CLINICAL FEATURES OF TYPE 1 AUTOIMMUNE POLYGLANDULAR SYNDROME]

Autoimmune polyglandular syndrome is a primary autoimmune disorder affecting two or more peripheral endocrine glands and responsible for their incompetence. It is frequently combined with various organ-specific non-endocrine diseases. Patients with this pathology need life-long replacement therapy and dynamic observation by endocrinologists and other specialists to monitor the effectiveness of the treatment and detect new components of the disease. We report a variant of type 1 autoimmune polyglandular syndrome. Special emphasis is laid on the importance of succession of actions of endocrinologists and specialists in related medical disciplines dealing with children and adult patients.