Autoimmune polyendocrinopathy-candidiasis-ectodermal-dystrophy (APECED) in Sicily: confirmation that R203X is the peculiar AIRE gene mutation

Autoimmune polyendocrine syndrome type 1: an Italian survey on 158 patients

BACKGROUND

Autoimmune Polyglandular Syndrome type 1 (APS-1) is a rare recessive inherited disease, caused by AutoImmune Regulator (AIRE) gene mutations and characterized by three major manifestations: chronic mucocutaneous candidiasis (CMC), chronic hypoparathyroidism (CH) and Addison's disease (AD).

METHODS

Autoimmune conditions and associated autoantibodies (Abs) were analyzed in 158 Italian patients (103 females and 55 males; F/M 1.9/1) at the onset and during a follow-up of 23.7 ± 15.1 years. AIRE mutations were determined.

RESULTS

The prevalence of APS-1 was 2.6 cases/million (range 0.5-17 in different regions). At the onset 93% of patients presented with one or more components of the classical triad and 7% with other components. At the end of follow-up, 86.1% had CH, 77.2% AD, 74.7% CMC, 49.5% premature menopause, 29.7% autoimmune intestinal dysfunction, 27.8% autoimmune thyroid diseases, 25.9% autoimmune gastritis/pernicious anemia, 25.3% ectodermal dystrophy, 24% alopecia, 21.5% autoimmune hepatitis, 17% vitiligo, 13.3% cholelithiasis, 5.7% connective diseases, 4.4% asplenia, 2.5% celiac disease and 13.9% cancer. Overall, 991 diseases (6.3 diseases/patient) were found. Interferon-ω Abs (IFNωAbs) were positive in 91.1% of patients. Overall mortality was 14.6%. The AIRE mutation R139X was found in 21.3% of tested alleles, R257X in 11.8%, W78R in 11.4%, C322fsX372 in 8.8%, T16M in 6.2%, R203X in 4%, and A21V in 2.9%. Less frequent mutations were present in 12.9%, very rare in 9.6% while no mutations in 11% of the cases.

CONCLUSIONS

In Italy, APS-1 is a rare disorder presenting with the three major manifestations and associated with different AIRE gene mutations. IFNωAbs are markers of APS-1 and other organ-specific autoantibodies are markers of clinical, subclinical or potential autoimmune conditions.

Levothyroxine and insulin requirement in autoimmune polyglandular type 3 syndrome: a real-life study

PURPOSE

To evaluate factors influencing the insulin and levothyroxine requirement in patients with autoimmune polyglandular syndrome type 3 (APS-3) vs. patients with type 1 diabetes mellitus (T1DM) and autoimmune hypothyroidism (AH) alone, respectively.

METHODS

Fifty patients with APS-3, 60 patients with T1DM and 40 patients with AH were included. Anthropometric, clinical and biochemical parameters were evaluated in all patients. Insulin requirement was calculated in patients with APS-3 and T1DM, while levothyroxine requirement was calculated in APS-3 and AH.

RESULTS

Patients with APS-3 showed higher age (p = 0.001), age of onset of diabetes (p = 0.006) and TSH (p = 0.004) and lower total insulin as U/day (p < 0.001) and U/Kg (p = 0.001), long-acting insulin as U/day (p = 0.030) and U/kg (p = 0.038) and irisin (p = 0.002) compared to T1DM. Patients with APS-3 had higher waist circumference (p = 0.008), duration of thyroid disease (p = 0.020), levothyroxine total daily dose (p = 0.025) and mcg/kg (p = 0.006), triglycerides (p = 0.007) and VAI (p = 0.010) and lower age of onset of thyroid disease (p = 0.007) than AH. At multivariate analysis, levothyroxine treatment and VAI were associated with insulin and levothyroxine requirement in APS-3, respectively. VAI was independently associated with insulin requirement in T1DM. Circulating irisin levels were independently associated with levothyroxine requirement in AH.

CONCLUSION

Patients with APS-3 show lower insulin requirement and higher levothyroxine requirement than T1DM and AH alone, respectively. Levothyroxine treatment and VAI affect insulin and levothyroxine requirement, respectively, in APS-3. In T1DM, adipose tissue dysfunction, indirectly expressed by high VAI, is associated with an increased insulin requirement, while circulating irisin levels influence the levothyroxine requirement in AH.

A novel mutation in autoimmune regulator gene causes autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy

BACKGROUND

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) is a rare autosomal recessive disease due to mutations in the autoimmune regulator (AIRE) gene, which encodes a transcription factor that induces the expression of peripheral tissue-specific antigens in medullary thymic epithelial cells.

AIM

The purpose of this study was to identify the underlying genetic cause in a Chinese family diagnosed with APECED.

METHOD

Peripheral blood samples were collected from family members. All exons of the AIRE gene and adjacent exon-intron sequences were amplified by PCR and subsequently sequenced. The functional consequence of the mutations was analyzed by cell transfection and in vitro assays.

RESULTS

A novel c.483_484insC mutation in exon 4 was identified, which resulted in a frame shift predicted to generate a truncated protein containing the first 163 AIRE amino acids followed by 52 aberrant amino acids. Confocal immunofluorescence microscopy of COS-7 cells transfected with wild-type and mutant AIRE constructs showed that wild-type AIRE protein was localized mainly in the nucleus, while mutant AIRE was localized mainly in the cytoplasm. A luciferase reporter assay showed that the identified mutation dramatically inhibited the transactivation activity of AIRE in vitro.

CONCLUSION

We identified a novel AIRE mutation which alters the intracellular location and transcription activity of AIRE, and has implications in the pathogenesis of APECED.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy: report of seven additional sicilian patients and overview of the overall series from sicily

BACKGROUND

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare recessive inherited disease caused by the mutation of the AIRE gene on chromosome 21. To date, 8 Sicilian patients have been described and the R203X AIRE mutation was found to be the most common in this region.

AIMS

(1) To describe 7 additional Sicilian APECED patients and to review all 15 Sicilian APECED patients who have been investigated by our group in the last years, and (2) to report a novel AIRE gene mutation.

RESULTS

Among the 3 cardinal features of APECED, hypoparathyroidism has been already detected in all 15 patients, whereas Addison's disease and chronic mucocutaneous candidiasis have so far been found in 10/15 and 12/15 cases, respectively. In 2 consanguineous cases, AIRE gene analysis revealed a novel mutation, named IVS13+2T, in homozygosis. R203X was the most common mutation in this region (30% of alleles and 46.6% of patients), followed by R257X (20% of alleles and 40% of patients).

CONCLUSIONS

Sicilian APECED patients are confirmed to have some peculiar characteristics from a clinical and genetic point of view. No correlations between genotype and phenotype were identified.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy from the pediatric perspective

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disease caused by mutations of the AutoImmune REgulator gene. The clinical spectrum of the disease encompasses several autoimmune endocrine and non-endocrine manifestations, which may lead to acute metabolic alterations and eventually life-threatening events. The clinical diagnosis is defined by the presence of at least two components of the classic triad including chronic mucocoutaneous candidiasis (CMC), chronic hypoparathyroidism (CH), Addison's disease (AD). Other common features of the disease are hypergonadotropic hypogonadism, alopecia, vitiligo, autoimmune hepatitis, Type 1 diabetes, gastrointestinal dysfunction. APECED usually begins in childhood. CMC is the first manifestation to appear, usually before the age of 5 yr, followed by CH and then by AD. The clinical phenotype may evolve over several years and many components of the disease may not appear until the 4th or 5th decade of life. The phenotypical expression of the syndrome shows a wide variability even between siblings with the same genotype. In view of this heterogeneity, an early diagnosis of APECED can be very challenging often leading to a considerable diagnostic delay. Therefore, clinicians should be aware that the presence of even a minor component of APECED in children should prompt a careful investigation for other signs and symptoms of the disease, thus allowing an early diagnosis and prevention of severe and life-threatening events. Aim of this review is to focus on clinical presentation, diagnosis and management of the major components of APECED in children particularly focusing on endocrine features of the disease.

APECED: A Paradigm of Complex Interactions between Genetic Background and Susceptibility Factors

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disease, caused by mutations of a single gene named Autoimmune regulator gene (AIRE) which results in a failure of T-cell tolerance. Central tolerance takes place within the thymus and represents the mechanism by which potentially auto-reactive T-cells are eliminated through the negative selection process. The expression of tissue-specific antigens (TSAs) by medullary thymic epithelial cells (mTECs) in the thymus is a key process in the central tolerance and is driven by the protein encoded by AIRE gene, the transcription factor autoimmune regulator (AIRE). A failure in this process caused by AIRE mutations is thought to be responsible of the systemic autoimmune reactions of APECED. APECED is characterized by several autoimmune endocrine and non-endocrine manifestations and the phenotype is often complex. Although APECED is the paradigm of a monogenic autoimmune disorder, it is characterized by a wide variability of the clinical expression even between siblings with the same genotype, thus implying that additional mechanisms, other than the failure of Aire function, are involved in the pathogenesis of the disease. Unraveling open issues of the molecular basis of APECED, will help improve diagnosis, management, and therapeutical strategies of this complex disease.

Autoimmune-polyendocrinopathy-candidiasis-ectodermal-dystrophy in Calabria: clinical, immunological and genetic patterns

Autoimmune polyendocrinopathy-candidiasis-ectodermal- dystrophy (APECED), also known as autoimmune polyendocrine syndrome type 1 (APS-1), is a very rare disease. Diagnosis requires the presence of at least two of three major clinical features: chronic mucocutaneous candidiasis, chronic hypoparathyroidism, and Addison's disease.

DESIGN

In this study, we analyzed Autoimmune Regulator (AIRE) gene mutations and genotype-phenotype correlation in APECED patients originating from Calabria, a region in the south of Italy.

PATIENTS AND METHODS

Four patients and their first-degree relatives were evaluated for clinical manifestations, autoantibody presence and AIRE gene mutations.

RESULTS

Three patients carried a homozygous W78R mutation on exon 2, typical of patients with APECED from Apulia; the fourth patient had a homozygous R203X mutation on exon 5, typical of APECED patients from Sicily. Clinical disease expression showed wide variability. Analysis of relatives allowed the identification of 6 heterozygotes, none of whom showed major findings of APECED.

CONCLUSIONS

No AIRE gene mutations specific to Calabria were found in patients with APS-1, but mutations similar to those in patients from Apulia and Sicily. Heterozygosity for AIRE gene mutation is not associated with major findings of APECED.

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy: insights into genotype-phenotype correlation

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is a rare autosomal recessive disease, caused by mutations of a single gene named autoimmune regulator gene (AIRE) which results in a failure of T cell tolerance within the thymus. Chronic mucocutaneous candidiasis, chronic hypoparathyroidism, and Addison's disease are the hallmarks of the syndrome. APECED is also characterized by several autoimmune endocrine and nonendocrine manifestations, and the phenotype is often complex. Moreover, even though APECED is a monogenic disease, its clinical picture is generally dominated by a wide heterogeneity both in the severity and in the number of components even among siblings with the same AIRE genotype. The variability of its clinical expression implies that diagnosis can be challenging, and a considerable delay often occurs between the appearance of symptoms and the diagnosis. Since a prompt diagnosis is essential to prevent severe complications, clinicians should be aware of all symptoms and signs of suspicion. The aim of this paper is to give an overview on the clinical presentation and diagnostic criteria of APECED and to focus on current knowledge on genotype-phenotype correlation.