Clues for early detection of autoimmune Addison's disease - myths and realities.

BACKGROUND: Early detection of autoimmune Addison's disease (AAD) is important as delay in diagnosis may result in a life-threatening adrenal crisis and death. The classical clinical picture of untreated AAD is well-described, but methodical investigations are scarce. OBJECTIVE: Perform a retrospective audit of patient records with the aim of identifying biochemical markers for early diagnosis of AAD. MATERIAL AND METHODS: A multicentre retrospective study including 272 patients diagnosed with AAD at hospitals in Norway and Sweden during 1978-2016. Scrutiny of medical records provided patient data and laboratory values. RESULTS: Low sodium occurred in 207 of 247 (84%), but only one-third had elevated potassium. Other common nonendocrine tests were largely normal. TSH was elevated in 79 of 153 patients, and hypoglycaemia was found in 10%. Thirty-three per cent were diagnosed subsequent to adrenal crisis, in whom electrolyte disturbances were significantly more pronounced (P < 0.001). Serum cortisol was consistently decreased (median 62 nmol L-1 [1-668]) and significantly lower in individuals with adrenal crisis (38 nmol L-1 [2-442]) than in those without (81 nmol L-1 [1-668], P < 0.001). CONCLUSION: The most consistent biochemical finding of untreated AAD was low sodium independent of the degree of glucocorticoid deficiency. Half of the patients had elevated TSH levels. Only a minority presented with marked hyperkalaemia or other nonhormonal abnormalities. Thus, unexplained low sodium and/or elevated TSH should prompt consideration of an undiagnosed AAD, and on clinical suspicion bring about assay of cortisol and ACTH. Presence of 21-hydroxylase autoantibodies confirms autoimmune aetiology. Anticipating additional abnormalities in routine blood tests may delay diagnosis.

Extended exome sequencing identifies BACH2 as a novel major risk locus for Addison's disease.

BACKGROUND: Autoimmune disease is one of the leading causes of morbidity and mortality worldwide. In Addison's disease, the adrenal glands are targeted by destructive autoimmunity. Despite being the most common cause of primary adrenal failure, little is known about its aetiology. METHODS: To understand the genetic background of Addison's disease, we utilized the extensively characterized patients of the Swedish Addison Registry. We developed an extended exome capture array comprising a selected set of 1853 genes and their potential regulatory elements, for the purpose of sequencing 479 patients with Addison's disease and 1394 controls. RESULTS: We identified BACH2 (rs62408233-A, OR = 2.01 (1.71-2.37), P = 1.66 × 10-15 , MAF 0.46/0.29 in cases/controls) as a novel gene associated with Addison's disease development. We also confirmed the previously known associations with the HLA complex. CONCLUSION: Whilst BACH2 has been previously reported to associate with organ-specific autoimmune diseases co-inherited with Addison's disease, we have identified BACH2 as a major risk locus in Addison's disease, independent of concomitant autoimmune diseases. Our results may enable future research towards preventive disease treatment.

The role of pleiotropy and linkage in genes affecting a sexual ornament and bone allocation in the chicken.

Sexual selection and the ornaments that inform such choices have been extensively studied, particularly from a phenotypic perspective. Although more is being revealed about the genetic architecture of sexual ornaments, much still remains to be discovered. The comb of the chicken is one of the most widely recognized sexual ornaments, which has been shown to be correlated with both fecundity and bone allocation. In this study, we use a combination of multiple intercrosses between White Leghorn populations and wild-derived Red Junglefowl to, first, map quantitative trait loci (QTL) for bone allocation and, second, to identify expression QTL that correlate and colocalize with comb mass. These candidate quantitative genes were then assessed for potential pleiotropic effects on bone tissue and fecundity traits. We identify genes that correlate with both relative comb mass and bone traits suggesting a combination of both pleiotropy and linkage mediates gene regulatory variation in these traits.

The transcription factors SOX9 and SOX10 are vitiligo autoantigens in autoimmune polyendocrine syndrome type I.

Vitiligo is common in the hereditary disorder autoimmune polyendocrine syndrome type I (APS I). Patients with APS I are known to have high titer autoantibodies directed against various tissue-specific antigens. Using sera from APS I patients for immunoscreening of a cDNA library from human scalp, we identified the transcription factors SOX9 and SOX10 as novel autoantigens related to this syndrome. Immunoreactivity against SOX9 was found in 14 (15%) and against SOX10 in 20 (22%) of the 91 APS I sera studied. All patients reacting with SOX9 displayed reactivity against SOX10, suggesting shared epitopes. Among the 19 patients with vitiligo, 12 (63%) were positive for SOX10 (p < 0.0001). Furthermore, three of 93 sera from patients with vitiligo unrelated to APS I showed strong reactivity against SOX10, which may indicate a more general role of SOX10 as an autoantigen in vitiligo.

Autoimmune polyendocrine syndrome type 1 (APS I) in Norway.

OBJECTIVE: The aim of the present study was to investigate Norwegian patients with autoimmune polyendocrine syndrome type I (APS I), with respect to occurrence and clinical presentation, reactivity towards different autoantigenes and mutations in the autoimmune regulator (AIRE) gene. PATIENTS: Twenty Norwegian patients from 15 families with APS I (11 males, nine females; mean age 26 years, range 4--54) were included by contacting all major hospitals in Norway. METHODS: Clinical data was collected from both patients and their physicians by the use of questionnaires and patient records. Autoantibodies were analysed using radioimmunoassays based on antigen synthesized by in vitro transcription and translation. AIRE mutations were determined by DNA sequence analysis. RESULTS: The prevalence of APS I in Norway was estimated to be about 1 : 80,000 individuals. We found about the same distribution of disease characteristics as has been reported in Finnish patients. The diagnosis was delayed in many individuals. In two thirds of the cases, the patients were admitted in Hospital with acute adrenal insufficiency or hypocalcaemic crisis. Forty percent of these patients already had one of the main disease manifestations. Four different mutations in the AIRE gene were found in the Norwegian cohort. A 13-bp deletion in exon 8 (1085--1097(del)) was the most frequent mutation, present in 22/40 (55%) of the alleles. Eighty-five percent of the patients had either autoantibodies against 21 hydroxylase or aromatic L-amino acid decarboxylase. Five of eight women (age > 13 years) had ovarian failure, and all of these had antibodies against side-chain cleavage enzyme (P = 0.0002). CONCLUSION: Norwegian patients with APS I clinically resemble patients from Finland and other European countries. The diagnosis APS I must be considered in children and adolescents with chronic mucocutaneous candidiasis, autoimmune adrenocortical failure or hypoparathyroidism in order to avoid fatal complications. Analysis of autoantibodies and mutational analysis of the AIRE gene are valuable diagnostic tools, especially in the early stages of the disease.

Pteridin-dependent hydroxylases as autoantigens in autoimmune polyendocrine syndrome type I.

Autoimmune polyendocrine syndrome type I (APS I) is characterized by autoantibodies, often directed towards tissue-specific enzymes in the affected organs. We have earlier reported the identification of tryptophan hydroxylase (TPH) and tyrosine hydroxylase (TH) as autoantigens in APS I associated with intestinal dysfunction and alopecia, respectively. These two enzymes, together with phenylalanine hydroxylase (PAH), constitute the group of biopterin-dependent hydroxylases, which all are involved in the biosynthesis of neurotransmitters. A clone encoding PAH was used for in vitro transcription/translation, followed by immunoprecipitation with sera from 94 APS I patients and 70 healthy controls. Of the APS I patients, 25% had PAH antibodies, and no reactivity was detected in the controls. No association with the main clinical components of APS I was found with PAH antibodies. Altogether, 59 sera from the 94 APS I patients reacted with at least one of TPH, TH, or PAH, whereas 35 showed no reactivity. Nineteen of the sera contained antibodies towards all enzymes, 12 to TPH only and 12 to TH only. No sera showed antibodies that reacted to only PAH. An immunocompetition assay demonstrated that the reactivity against PAH represents a cross-reactivity with TPH, whereas antibodies against TPH and TH are directed towards epitopes unique for the two enzymes.

Identification of tyrosine hydroxylase as an autoantigen in autoimmune polyendocrine syndrome type I.

Patients with the autosomal recessively inherited autoimmune polyendocrine syndrome type I (APS I) have autoantibodies directed against several endocrine and nonendocrine organs. In this study a new autoantigen related to this syndrome, tyrosine hydroxylase, was identified in sera from patients with alopecia areata through immunoscreening of a scalp cDNA library. Immunoreactivity against in vitro expressed tyrosine hydroxylase was found in 41 (44%) of the 94 APS I patients studied and this reactivity correlated with the presence of alopecia areata (P = 0.02). These findings further stress the importance of enzymes involved in neurotransmitter biosynthesis as important immune targets in APS I.

Autoantibodies against aromatic L-amino acid decarboxylase identifies a subgroup of patients with Addison's disease.

Autoantibodies against aromatic L-amino acid decarboxylase (AADC) are present in about 50 percent of sera from patients with autoimmune polyendocrine syndrome type I (APS I) but absent in sera from patients with different organ-specific autoimmune diseases, such as insulin-dependent diabetes mellitus, Hashimoto's thyroiditis, and Graves' disease. AADC is expressed in the pancreatic beta-cells, the liver, and the nervous system; and the presence of AADC antibodies has been shown to correlate to hepatitis and vitiligo in APS I patients. Among 101 investigated patients with autoimmune Addison's disease, 15 had high titers of AADC antibodies. According to the clinical characteristics of these patients, only 3 had APS I. The remaining 12 had either isolated Addison's disease or associated diabetes mellitus, hypothyroidism, vitiligo, alopecia, gonadal failure, and pernicious anemia. Autoantibodies against 21-hydroxylase were present in 9 of 12, whereas autoantibodies against side-chain cleavage enzyme and 17alpha-hydroxylase were present in 3 of 12. Two patients had only autoantibodies against AADC. DNA was available from 3 of these 12 patients. One of the patients, a woman with Addison's disease, autoimmune thyroiditis, and premature menopause was heterozygous for a point mutation (G1021A, Val301Met) in the first plant homeodomain zinc finger domain of the autoimmune regulator (AIRE) gene. The presence of AADC autoantibodies identifies patients with APS I and a subgroup of Addison patients who may have a milder atypical form of APS I or represent a distinct entity. Measurement of autoantibodies against AADC should be included in the evaluation of Addison's disease.

Antibodies against hair follicles are associated with alopecia totalis in autoimmune polyendocrine syndrome type I.

In the autosomal recessively inherited autoimmune polyendocrine syndrome type I (APS I) patients have autoantibodies directed against several endocrine and nonendocrine organs. Alopecia areata is present in about one-third of the patients and usually in the more severe forms, alopecia universalis or totalis. Sera from 39 patients with APS I, diluted 1:150, were used in indirect immunofluorescence staining of cryo-sections from normal human scalp. Two hair follicle staining patterns were observed. A cytoplasmic staining of the differentiating matrix, cuticle, and cortex keratinocytes in the anagen hair follicle was seen in five (13%) APS I sera. All these five patients had alopecia totalis, representing 63% of the eight patients with alopecia totalis (p < 0.0001). Furthermore, four (10%) of the APS I sera stained the nuclei of the melanocytes in the hair follicle. Two of these patients had vitiligo. None of 20 healthy control sera stained the keratinocyte cells or the melanocyte nuclei. These data show that many patients with APS I have high-titer autoantibodies directed against the anagen matrix, cuticle, and cortex keratinocytes and a melanocyte nuclear antigen, and also that the hair follicle keratinocyte staining is associated with alopecia, especially alopecia totalis. This study emphasizes the role of the differentiating anagen keratinocytes as an important structure in the autoimmune etiology of alopecia, both in APS I and at least in a subgroup of patients with alopecia areata unrelated to APS I.

Tryptophan hydroxylase autoantibodies and intestinal disease in autoimmune polyendocrine syndrome type 1.

Tryptophan hydroxylase antibodies, associated with gastrointestinal disease in autoimmune polyendocrine syndrome type 1, are specific for this disease and not present in patients with other bowel disorders or healthy controls.

Identification of tryptophan hydroxylase as an intestinal autoantigen.

BACKGROUND: Autoimmune polyendocrine syndrome type 1 (APS1) is an autosomal recessive disorder with both endocrine and non-endocrine features. Periodic gastrointestinal dysfunction occurs in 25-30% of APS1 patients. We aimed to identify an intestinal autoantigen. METHODS: A human duodenal cDNA library was immunoscreened with serum samples from APS1 patients. A positive clone was identified and used for in-vitro transcription and translation, followed by immunoprecipitation with serum samples from 80 APS1 patients from Norway, Finland, and Sweden. Sections of normal and APS1-affected small intestine were immunostained with serum from APS1 patients and specific antibodies. An enzyme-inhibition assay was used to characterise the autoantibodies. FINDINGS: We isolated a cDNA clone coding for tryptophan hydroxylase. 48% (38/80) of APS1 patients had antibodies to tryptophan hydroxylase, whereas no reactivity to this antigen was detected in patients with other autoimmune diseases (n=372) or healthy blood donors (n=70). 89% (17/19) of APS1 patients with gastrointestinal dysfunction were positive for antibodies to tryptophan hydroxylase, compared with 34% (21/61) of patients with no gastrointestinal dysfunction (p<0.0001). Serum from antibody-positive APS1 patients specifically immunostained tryptophan-hydroxylase-containing enterochromaffin cells in normal duodenal mucosa. No serotonin-containing cells were seen in duodenal biopsy samples from APS1 patients. Serum from antibody-positive APS1 patients almost completely inhibited activity of tryptophan hydroxylase. INTERPRETATION: Tryptophan hydroxylase is an endogenous intestinal autoantigen in APS1, and there is an association between antibodies to the antigen and gastrointestinal dysfunction. Analysis of antibodies to tryptophan hydroxylase may be a valuable diagnostic tool to predict and monitor gastrointestinal dysfunction in APS1.