High intrafamilial variability in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy: a case study

Analysis of a series of Italian APECED patients with autoimmune hepatitis and gastro-enteropathies

Introduction

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome is a rare monogenic disease determined by biallelic mutations in AIRE gene, which encodes a transcription factor essential for central immune tolerance. Classic diagnosis is determined by the presence of two of the main APECED clinical diseases: chronic mucocutaneous candidiasis, chronic hypoparathyroidism, and Addison's disease. Non-endocrine autoimmunity, involving the liver, intestine, eyes, and kidneys, is generally reported in a minority of European patients, while American APECED patients have a higher tendency of developing organ-specific non-endocrine manifestations early in life. This observation led to the revision of the diagnostic criteria to permit earlier diagnosis based on the appearance of one classic triad symptom or one non-classical manifestation at a young age in the presence of IFNωAbs or AIRE mutations (Ferre-Lionakis criteria).

Patients and methods

We analyzed the clinical, genetic, and autoantibody (Ab) profiles in a series of 14 pediatric Italian APECED patients with gastrointestinal manifestations (seven male and seven female patients). Ten patients presented hepatitis (APECED-associated hepatitis (APAH)), while seven were affected by constipation, diarrhea, and malabsorption. Four patients had developed APAH before classic triad symptoms.

Results

Based on the age of appearance of non-endocrine manifestations including APAH and gastro-enteropathy, the Ferre-Lionakis criteria would have allowed an expedited diagnosis in 11/14 patients. Abs to tryptophan hydroxylase (TPHAb) and hepatic aromatic l-amino acid decarboxylase (AADC) were significantly associated with APECED patients of the present series. Abs to cP4501A2 were detectable in the serum of 4/8 patients with APAH, and Abs to cP4502A6 were detectable in 3/8 patients. AADC Abs tested positive in 5/7 patients, which is indicative of gastrointestinal dysfunction in APECED and TPHAb in 5/7 patients with gastrointestinal dysfunction. IFNAb was significantly associated with the syndrome.

Conclusion

Although Ferre-Lionakis expanded criteria applied to the American cohorts of APECED patients would require validation in independent large cohorts of European patients, the results of this study emphasize the importance to evaluate the presence and the age of appearance of APAH and autoimmune enteropathy even in European cohorts for an earlier APECED diagnosis. An earlier APECED diagnosis would also allow the prevention of episodes of life-threatening hypocalcemic seizures and adrenal crisis, which are the main manifestations of undiagnosed APECED.

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.

Novel Findings into AIRE Genetics and Functioning: Clinical Implications

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), formerly known as autoimmune polyendocrine syndrome type 1, is a paradigm of a monogenic autoimmune disease caused by mutations of a gene, named autoimmune regulator (AIRE). AIRE acts as a transcription regulator that promotes immunological central tolerance by inducing the ectopic thymic expression of many tissue-specific antigens. Although the syndrome is a monogenic disease, it is characterized by a wide variability of the clinical expression with no significant correlation between genotype and phenotype. Indeed, many aspects regarding the exact role of AIRE and APECED pathogenesis still remain unraveled. In the last decades, several studies in APECED and in its mouse experimental counterpart have revealed new insights on how immune system learns self-tolerance. Moreover, novel interesting findings have extended our understanding of AIRE's function and regulation thus improving our knowledge on the pathogenesis of APECED. In this review, we will summarize recent novelties on molecular mechanisms underlying the development of APECED and their clinical implications.

Cutaneous vasculitis in patients with autoimmune polyendocrine syndrome type 1: report of a case and brief review of the literature

Background

Autoimmune polyendocrine syndrome type 1, also known as autoimmune polyendocrinopathy-candidiasis-ectodermal-dystrophy, is a rare autosomal recessive disease due to pathogenic variants in the AIRE gene. Classic features of the syndrome are mucocutaneous candidiasis, chronic idiopathic hypoparathyroidism and Addison disease. However, other endocrine and non-endocrine components, may occur with a different prevalence. In addition to ectodermal features, which are quite common features of the disease, APS 1 patients may experience other types of skin alterations, such as vasculitic skin rash. An early diagnosis of APS 1 can be very challenging, due to the high clinical heterogeneity, and a considerable delay may occur between the appearance of symptoms and the diagnosis.

Case presentation

We report on a girl affected by APS 1 who presented with cutaneous vasculitis when she was seven-months old, some years before the onset of the common components of the disease.

Conclusion

Clinical picture of APS 1 may be characterized by isolated rare or atypical autoimmune or immune-mediated manifestations, even years before the onset of the classic components of the disease. Among these uncommon features, skin rashes of variable form and duration may occur, most of them being associated with histopathological features of vasculitis. Our case suggests that cutaneous vasculitis may represent a first sign of APS 1. The clinical significance of cutaneous vasculitis in the context of APS 1 is still debated. It may represent a rare, unusual, early component of the disease or a clinical manifestation secondarily related to the typical APS 1 components (i.e. autoimmune thyroid disease), which are frequently associated with rheumatologic-like signs and symptoms. Alternatively, it may be the expression of an independent disease co-occuring with APS 1. In conclusion, our case suggests that children presenting with unexplained vasculitic skin rash should be followed-up in order to early identify APS 1.

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.

Non-autoimmune subclinical hypothyroidism due to a mutation in TSH receptor: report on two brothers

Subclinical hypothyroidism (SH) is a condition characterized by a mild persistent thyroid failure. The main cause is represented by autoimmune thyroiditis, but mutations in genes encoding proteins involved in TSH pathway are thought to be responsible for SH, particularly in cases arising in familial settings. Patients with the syndrome of TSH unresponsiveness may have compensated or overt hypothyroidism with a wide spectrum of clinical and morphological alterations depending on the degree of impairment of TSH-receptor (TSH-R) function. We describe the case of two brothers with non autoimmune SH carrying the same heterozygous mutation in the extracellular domain of TSH-R and presenting with different clinical, biochemical and morphological features. The first one had only a slight persistent elevation of TSH, a normal thyroid ultrasound and did never require l- thyroxine (L-T4) replacement treatment. The second one had a neonatal persistent moderate TSH levels increase associated with a thyroid gland hypoplasia and was treated with L-T4 since the first months of life.

These two cases support the recent association of TSH-R mutations inheritance as an autosomal dominant pattern with variable expressivity and suggest that the decision to start replacement therapy in patients with persistent SH due to TSH resistance should be individualized.

Precocious puberty in Turner Syndrome: report of a case and review of the literature

INTRODUCTION

Turner Syndrome (TS) is caused by monosomy or structural abnormalities of the X chromosome, with a prevalence of about 1/2000 females live birth. Most important clinical features of TS are short stature and gonadal failure. Approximately one third of girls with TS may undergo spontaneous puberty. Here we report on the case of a girl with a rare 45X0/47XXX mosaic TS exhibiting a precocious puberty.

CASE REPORT

The patient was diagnosed with TS at the age of 4 years, upon a diagnostic work-up for dysmorphic features. Chromosome analysis revealed a mosaic karyotype (45X0/47XXX). She presented with normal height and normal growth velocity so that Growth Hormone (GH) therapy was not started. She was referred to our Department at the age of 7 years and 10 months, because of vaginal bleeding. A physical examination revealed a Tanner stage III for breast and Tanner stage III for pubic hair development. Height and weight were within the normal range for age. Psychological evaluation showed moderate global developmental delay, together with emotional and social immaturity and reading difficulties. The growth rate was accelerated. Her bone age was 10 years. Pelvic ultrasound demonstrated increased size for age of both the uterus and the ovaries, with bilateral ovarian follicles. GnRH stimulation test revealed pubertal response of gonadotropins (peak LH 22.5 mIU/ml). MRI of the brain was normal. These clinical, radiologic and laboratory findings were consistent with a diagnosis of idiopathic central precocious puberty; therefore, GnRH analog therapy was started, in order to slow pubertal progression and to preserve adult stature. Furthermore, GH treatment was added to further improve adult height.

CONCLUSION

Our case highlights the possibility of precocious puberty as an atypical clinical feature of TS. Thus, precocious puberty may occur in TS girls when a dosage compensation by the cell line with more than two X chromosomes allows normal ovarian function. GnRH analog therapy in addition to GH treatment should be recommended in TS girls with precocious puberty in order to slow pubertal progression and to preserve adult stature.

Clinical Heterogeneity in two patients with Noonan-like Syndrome associated with the same SHOC2 mutation

Noonan-like syndrome with loose anagen hair (NS/LAH; OMIM #607721) has been recently related to the invariant c.4A > G missense change in SHOC2. It is characterized by features reminiscent of Noonan syndrome. Ectodermal involvement, short stature associated to growth hormone (GH) deficiency (GHD), and cognitive deficits are common features. We compare in two patients with molecularly confirmed NS/LAH diagnosis, the clinical phenotype and pathogenetic mechanism underlying short stature. In particular, while both the patients exhibited a severe short stature, GH/IGFI axis functional evaluation revealed a different pathogenetic alteration, suggesting in one patient an upstream alteration (typical GHD) and in the other one a peripheral GH insensitivity.

Since only a few cases of NS/LAH associated to SHOC2 mutations have been so far described, the complex phenotype of the syndrome and the exact mechanism impairing GH/IGFI axis still remain to be elucidated and studies on larger cohort of subjects are needed to better delineate this syndrome.

Acute adrenal failure as the presenting feature of primary antiphospholipid syndrome in a child

Introduction

Antiphospholipid syndrome (APS) is characterized by recurrent arterial and venous thrombosis and detection of antiphospholipid antibodies (aPLs). This syndrome may be associated with connective tissue disorders, or with malignancies, but it may also appear in isolated form (primary APS). We report on a pediatric patient presenting with acute adrenal failure as the first manifestation of primary APS.

Case report

A previously healthy 11-year-old boy developed fever, abdominal pain, and vomiting. An abdominal computed tomography scan showed nodular lesions in the adrenal glands. He was referred to our Department and a diagnosis of APS and acute adrenal failure was considered, based on positive aPLs (IgG and IgM), elevated ACTH levels and low cortisol levels. Other features were anemia, thrombocytopenia, elevated inflammatory parameters, hypergammaglobulinemia, prolonged partial thromboplastin time, positive antinuclear, anticardiolipin, anti-platelet antibodies, with negative double-stranded DNA antibodies. Lupus anticoagulant and Coomb’s tests were positive. MRI revealed a bilateral adrenal hemorrhage. A treatment with intravenous metylprednisolone, followed by oral prednisone and anticoagulant, was started, resulting in a progressive improvement. After 2 months he also showed hyponatremia and elevated renine levels, indicating a mineralcocorticoid deficiency, requiring fludrocortisones therapy.

Conclusion

The development of acute adrenal failure from bilateral adrenal haemorrhage in the context of APS is a rare but life-threatening event that should be promptly recognized and treated. Moreover, this case emphasizes the importance of the assessment of aPLs in patients with acute adrenal failure in the context of an autoreaction.

A case of galactosemia misdiagnosed as cow's milk intolerance

We report on a female patient affected by galactosemia in whom the diagnosis was obscured by the concomitant presence of manifestations suggesting a cow's milk intolerance. This case exemplifies the problems in reaching a correct diagnosis in patients with metabolic diseases.

Altered regulatory mechanisms governing cell survival in children affected with clustering of autoimmune disorders

Clustering of Autoimmune Diseases (CAD) is now emerging as a novel clinical entity within monogenic immune defects with a high familial occurrence. Aim of this study is to evaluate the regulatory mechanisms governing cell survival, paying a particular attention to Fas-induced apoptosis, in a cohort of 23 children affected with CAD. In 14 patients, Fas stimulation failed to induce cell apoptosis and in 1 case it was associated with Fas gene mutation. Our study highlights the importance to evaluate cell apoptosis in the group of children with CAD, which, with this regard, represents a distinct clinical entity.

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.