Human Leukocyte Antigen (HLA) Subtype-Dependent Development of Myasthenia Gravis, Type-1 Diabetes Mellitus, and Hashimoto Disease: A Case Report of Autoimmune Polyendocrine Syndrome Type 3

Co-existence of Type 1 Diabetes Mellitus and Myasthenia Gravis: A Case Report and Review of the Literature

Background/Objective

Type 1 diabetes (T1D) and myasthenia gravis (MG) are autoimmune conditions that rarely co-occur. Here, we report a child with MG who subsequently developed T1D.

Case report

An 11-year-old girl with seropositive MG diagnosed at 4 years of age presented with muscle pain, cramps, and weight loss of 3.5 kg over 4 months. Her MG was in remission on daily pyridostigmine. She denied polyuria, polydipsia, recent illnesses, or other medications. She was prepubertal and had stable vitals with normal systemic examination. Initial work up for a probable diagnosis of rhabdomyolysis showed hyperglycemia and glucosuria. She had ketosis without acidosis. Diabetes autoantibodies were positive (anti-glutamic acid decarboxylase antibody 113.5 IU/mL (reference range < 5 IU/mL), anti-zinc transporter 8 antibody > 500 U/mL (reference range < 15 IU/mL)). Screening for autoimmune thyroid disease and celiac disease was negative. Patient was diagnosed with T1D and was started on subcutaneous insulin.

Discussion

The co-existence of MG and T1D is rare. All the 4 prior reported patients from Europe were diagnosed with T1D prior to or concurrently with MG. In contrast, our patient was first diagnosed with MG and subsequently diagnosed with T1D 7 years later.

Conclusions

Consider screening for T1D in patients with MG and offering treatment to those above 8 years and older with stage 2 T1D to delay its onset. Along with other causes, T1D should also be considered when patients with MG present with nonspecific symptoms such as fatigue and weight loss.

Microbiome Metabolites and Thyroid Dysfunction

Thyroid diseases are common conditions that have a negative impact on the health of all populations. The literature sheds light on the differences in the composition of the intestinal microbiota in patients suffering from thyroid diseases compared to healthy individuals. The microbiome affects the proper functioning of the thyroid gland, and the existence of the gut–thyroid axis is discussed in the context of both thyroid diseases and intestinal dysbiosis. The purpose of this review is to describe associations between the microbiome and its metabolites and thyroid dysfunction. We try to explain the role of the microbiome in the metabolism of thyroid hormones and the impact of thyroid autoimmune diseases. In addition, we raise issues related to the influence of bacterial metabolites, such as short-chain fatty acids or secondary bile acids, in the functioning of the thyroid gland. Last but not least, we explored the interactions between the gut microbiota and therapeutics and supplements typically administered to patients with thyroid diseases.

Immune Checkpoint Inhibitors-Related Thyroid Dysfunction: Epidemiology, Clinical Presentation, Possible Pathogenesis, and Management

Immune checkpoint inhibitors (ICIs) are a group of drugs employed in the treatment of various types of malignant tumors and improve the therapeutic effect. ICIs blocks negative co-stimulatory molecules, such as programmed cell death gene-1 (PD-1) and its ligand (PD-L1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), reactivating the recognition and killing effect of the immune system on tumors. However, the reactivation of the immune system can also lead to the death of normal organs, tissues, and cells, eventually leading to immune-related adverse events (IRAEs). IRAEs involve various organs and tissues and also cause thyroid dysfunction. This article reviews the epidemiology, clinical manifestations, possible pathogenesis, and management of ICIs-related thyroid dysfunction.

Type 1 Diabetes and Autoimmune Thyroid Disease-The Genetic Link

Type 1 diabetes (T1D) and autoimmune thyroid disease (AITD) are the most frequent chronic autoimmune diseases worldwide. Several autoimmune endocrine and non-endocrine disorders tend to occur together. T1D and AITD often cluster in individuals and families, seen in the formation of autoimmune polyendocrinopathy (AP). The close relationship between these two diseases is largely explained by sharing a common genetic background. The HLA antigens DQ2 (DQA1*0501-DQB1*0201) and DQ8 (DQA1*0301-DQB1*0302), tightly linked with DR3 and DR4, are the major common genetic predisposition. Moreover, functional single nucleotide polymorphisms (or rare variants) of various genes, such as the cytotoxic T-lymphocyte- associated antigen (CTLA4), the protein tyrosine phosphatase non-receptor type 22 (PTPN22), the interleukin-2 Receptor (IL2Ra), the Vitamin D receptor (VDR), and the tumor-necrosis-factor-α (TNF) that are involved in immune regulation have been identified to confer susceptibility to both T1D and AITD. Other genes including cluster of differentiation 40 (CD40), the forkhead box P3 (FOXP3), the MHC Class I Polypeptide-Related Sequence A (MICA), insulin variable number of tandem repeats (INS-VNTR), the C-Type Lectin Domain Containing 16A (CLEC16A), the Erb-B2 Receptor Tyrosine Kinase 3 (ERBB3) gene, the interferon-induced helicase C domain-containing protein 1 (IFIH1), and various cytokine genes are also under suspicion to increase susceptibility to T1D and AITD. Further, BTB domain and CNC homolog 2 (BACH2), C-C motif chemokine receptor 5 (CCR5), SH2B adaptor protein 3 (SH2B3), and Rac family small GTPase 2 (RAC2) are found to be associated with T1D and AITD by various independent genome wide association studies and overlap in our list, indicating a strong common genetic link for T1D and AITD. As several susceptibility genes and environmental factors contribute to the disease aetiology of both T1D and AITD and/or AP subtype III variant (T1D+AITD) simultaneously, all patients with T1D should be screened for AITD, and vice versa.