ISSN: 1301-2193 E-ISSN: 1308-9846
  • Turkish Journal of
    Endocrinology and Metabolism

Introduction

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy APECED, also called APS I, usually appears in childhood at age 3-5 years or in early adolescence. It is defined by a persistent fungal infection as chronic mucocutaneous candidiasis (CMC), the presence of hypoparathyroidism (HP), and Addison’s disease (AD) (1,2,3). CMC is often the first manifestation, followed by HP and AD, which can develop at any age. Consequently, lifelong follow-up is important to allow the early detection of additional components (4,5,6,7,8). Type 1 diabetes mellitus (DM), primary hypogonadism, autoimmune thyroid disease, and lymphocytic hypophysitis may be seen as accompanying endocrinopathies. Various gastro-intestinal tract and hepato-biliary system diseases such as chronic atrophic gastritis, pernicious anemia, celiac disease, malabsorption, autoimmune hepatitis, and cholelithiasis may develop throughout life. Skin and associated tissues can be affected by some autoimmunity like in vitiligo and alopecia areata or may be involved in ectodermal dystrophy (1,2,9,10). The highest prevalence of the rare APS I has been found in populations which are characterized by a high degree of consanguinity or who are descendants of small founder populations, particularly in Iranian Jews 1: 9,000; Sardanian 1: 14500 and Finns 1: 25,000. APS I presents both in the sporadic and familial forms with monogenic autosomal recessive inheritance in a single gene (6,11,12). APECED (OMIM #240300), is an autosomal-recessive disease caused by mutations in the AIRE gene on chromosome 21q22.3. The AIRE gene consists of 14 exons and codes for a 545-amino acid protein (13,14). The phenotype of APECED is highly variable. However, conclusions regarding genotype-phenotype correlations have not been possible.

Materials and Methods

Case 1

The patient was born to Caucasian, non-consanguineous parents in 1984. At 8 years of age she developed recurrent CMC in her mouth, successfully treated with local and systemic anti fungal therapy. She developed vitiligo at 14 years of age. Total dental prosthesis was made due to severe dental enamel hypoplasia at 17 years of age. In the year 2005, she was admitted to the department of dermatology with signs and symptoms of severe CMC. She had a history of frequent upper respiratory tract infections and irregular menstrual cycles. No specific condition was found in her family history. In her physical examination there were common candidal plaques on her oral mucosa and corners of the lips. Total dental prosthesis was noticed. She had dystrophic changes on each thumb and nail. Chovostek’s and Trousseau’s signs were positive. In the laboratory investigation hypocalcaemia, hyperphosphatemia, undetectable parathyroid hormone (PTH), and normal vitamin-D levels were detected. 24-hour urinary excretion of calcium (Ca) and phosphorus (P) were decreased. There were no clinical and laboratory signs of hypocortisolism. Basal adrenocorticotropic hormone (ACTH), cortisol and stimulated cortisol levels with 250 μg tetracosactide (Synacthen®) were within normal ranges. Pituitary, adrenal, and sex hormone profiles were also within normal ranges. She was diagnosed with APECED syndrome with signs and symptoms of two major and three accompanying criteria. Her clinical characteristics related to APECED syndrome and time of diagnosis of these entities are shown in Table 1. Fluconazole 150 mg/day, calcium 3 gr/day, and calcitriol 1 μg/day were administered orally as therapy. Then she, her father and 3 sisters were invited to our medical genetic clinic for genetic examination. Genetic evaluation of her mother could not be performed since she died due to brain tumor 14 years ago.

Case 2

The patient was born to Caucasian, non-consanguineous parents in 1986. At 3 years of age she developed HP with signs of severe hypocalcaemia. In the laboratory investigation hypocalcaemia, hyperphosphatemia, undetectable parathyroid hormone PTH, and normal vitamin-D levels were detected. Twenty four hours urinary excretion of calcium (Ca) and phosphorus (P) were decreased. Twenty-two-year-old patient did not have any other pathological detection while he was taking Ca and calsitriol treatment meanwhile the patient applied to the dermotology clinic with total alopecia, nail dystrophy and oral candidiasis. There were no clinical and laboratory signs of hypocortisolism. Basal adrenocorticotropic hormone ACTH, cortisol and stimulated cortisol levels with 250 μg tetracosactide (Synacthen®) were within normal ranges. Pituitary, adrenal, and sex hormone profiles were also within normal ranges. No specific condition was found in her family history. She was diagnosed with APECED syndrome with signs and symptoms HP, mucocutaneous candidiasis and ectodermal displasia. Her clinical characteristics related to APECED syndrome and time of diagnosis of these entities are also shown in Table 1. Calcium 2-4 gr/day, and calcitiriol 1 μg/day and antifungal treatment were administered orally as therapy. Then she, her parents, 2 brothers and 2 sisters were invited to our medical genetic clinic for genetic examination.

Genetic Assessment

We performed mutation analysis of the AIRE gene on the DNA extracted from the peripheral blood of two patients and all their family members, a total of 12 persons. Mutation analysis for AIRE gene (GenBank Z97990.1) was performed by sequencing all the 14 exons and the intron-exon boundaries of the AIRE gene as described earlier (Figure 1) (15). Sequencing was done in both directions according to the Big Dye Terminator Cycle Sequencing protocol using the ABI3730x1 DNA analyzer (Applied Biosystems) in National Public Health Institute, Helsinki, Finland. While mutation analysis of the AIRE gene showed that index case (patient 1) was homozygous for the pathogenic mutation c.769C>T (p.R257X; g.8473C>T), and her father and all 3 sisters were heterozygous for this mutation (Figure 1), no mutation was found in the second patient and all of her family members.

Discussion

APECED syndrome is one of the few known organ-specific autoimmune diseases caused by mutations in a single gene. The genetic penetrance of APECED is 100%, i.e. an individual inheriting two faulty alleles will inevitably develop the disease. However phenotypic manifestations of the disease vary largely, prompting the idea of other genetic and/or environmental factors contributing to clinical presentation of the disease (16,17,18,19). Actually HLA-genotypes have been shown to modify the APECED phenotype (15,20).

AIRE gene, responsible for APECED, is 13 kb in length and its 14 exons code for a protein product of 545 amino acids. The AIRE protein contains motifs indicative of a transcription regulator including a conserved nuclear localization signal, two PHD zinc-finger motifs, four LXXLL nuclear receptor binding motifs, and a proline rich region (Figure 2).

The nonsense mutation 769C>T/R257X, detected also in our first patient, causes an Arg codon to turn into a premature STOP codon and potentially leads to a truncated 256 residue protein lacking both PHD finger domains. Assays in transfected cells show that deletion of both PHD fingers severely reduces the homomultimerization of the protein and inhibits totally its transactivation capacity (21). However, it remains to be shown whether the truncated R257X protein is actually produced in patient cells. This mutation was initially described as Finn-major mutation and detected in 89% of Finnish APECED chromosomes examined (6,16). Later, it has also been reported in various populations (North Italian, American Caucasian, Swiss, British, New Zealander, Swedish, Dutch, German, French, Czech, Hungarian, Polish, Austrian, Slovenian, Croatian, and Russian), underlining the cross-ethnicity nature of the mutation (22,23). The mutations of the AIRE gene observed in APECED has been shown to be responsible for the alteration in the immunologic tolerance in humans. Subsequently, the increasing knowledge of the biological role of the AIRE gene has lead to new understanding on the mechanisms regulating tolerance and autoimmunity (24,25).

In a series of 68 Finnish cases reported by Ahonen and co-workers, all patients had chronic candidiasis at some time, 79% had HP, 72% had Addison’s disease, and 51% had all the three of these classical components. Gonadal failure (60% in women, 14% in men) and hypoplasia of the dental enamel (77%) were also frequent findings. Other manifestations occurring less frequently included alopecia (29%), vitiligo (13%), intestinal malabsorption (18%), type 1 diabetes (18%), pernicious anemia (13%), chronic active hepatitis (12%), and hypothyroidism (4%). The major mutation in the AIRE gene was R257X (6). Collins et al. investigated and published same clinical findings as dermatological manifestations of APECED in 18 Irish patients (5). In another report Buzi and co workers published 3 patients with APECED syndrome who had R257X mutation of the AIRE gene and had similar clinical findings as in our first case and Finn cases. Like in our family, heterozygous mutations were found in the patient’s family members in this report as well (4). In our series CMC, HP, ectodermal dysplasia, vitiligo, and R257X mutation were demonstrated in patient 1, HP, CMC, and ectodermal dysplasia were demonstrated in patient 2, in whom no mutation was detected. Although mutational analysis revealed R257X mutation in one of our cases and her family investigation, most of our clinical and genetic findings were in parallel with the reports in the literature. Besides a significant association between the rare allele (C961) of the AIRE polymorphism at position 961 and alopecia areata, the fact that women had earlier onset of HP and were younger at the time of diagnosis than men had been reported in the different reports (23,26). Walls and co-workers had pointed that enamel hypoplasia may precede the onset of HP and, despite adequate replacement therapy, may also affect teeth forming after the onset of HP (7). Gylling found a clear gender linkage with lower and later incidence in male and described protective effect of male sex on hypoparathyroidism in APECED (27). In our series chronologic development order of APECED signs and symptoms in patient 1 was similar to the findings of this study.

In conclusion, although our report is a single case and family investigation, most of the clinical and genetic findings of our serial were in parallel with the reports in the literature. Due to the high frequency of consanguineous marriages in Turkey, genetic counseling and detailed observations of family members are necessary in families with heterozygote carriers. Patients with APECED syndrome need life-long treatment and follow-up to detect further disease components. Increased awareness of APECED, combined with mutational analysis of the AIRE gene, will aid diagnosis and may prevent serious and fatal complications.

Acknowledgments:

Special thanks to Ismo Ulmanen and Tania Ilmarine (Department of Molecular Medicine, National Public Health Institute, Biomedicum, Helsinki, Finland) for their kindly cooperation and doing genetic analyses of all patients.

The skillful technical assistance of Anne Vikman in the genotyping is acknowledged.

Ethics Committee Approval: The study protocol was approved by Uludağ University Medical School Ethics Committee, Informed Consent: The study was conducted after obtaining informed consents from all participants, Concept: Metin Güçlü, Hakan Cangül, Design: Metin Güçlü, Hakan Cangül, Data Collection or Processing: Metin Güçlü, Hakan Cangül, Analysis or Interpretation: Hakan Cangül, Literature Search: Metin Güçlü, Hakan Cangül, Writing: Metin Güçlü, Hakan Cangül, Canan Ersoy, Peer-review: Externally peer-reviewed, Conflict of Interest: No conflict of interest was declared by the authors, Financial Disclosure: The study was financially supported by the 6th framework EU program EURAPS (IU, TI).

References

1.    Betterle C, Zanchetta R. Update on autoimmune polyendocrine syndromes (APS). Acta Biomed. 2003;74:9-33.
2.    Perheentupa J, Miettinen A. Autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy. In: Eisenbarth GS, ed. Endocrine and Organ Specific Autoimmunity. Austin; Tex RG Landes Company; 1999:19-40.
3.    Dittmar M, Kahaly GJ. Polyglandular autoimmune syndromes: immunogenetics and long-term follow-up. J Clin Endocrinol Metab. 2003;88:2983-2992.
4.    Buzi F, Badolato R, Mazza C, Giliani S, Notarangelo LD, Radetti G, Plebani A, Notarangelo LD. Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome: time to review diagnostic criteria? J Clin Endocrinol Metab. 2003;88:3146-3148.
5.    Collins SM, Dominguez M, Ilmarinen T, Costigan C, Irvine AD. Dermatological manifestations of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome. Br J Dermatol. 2006;154:1088-1093.
6.    Ahonen P, Myllarniemi S, Sipila I, Perheentupa J. Clinical variation of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) in a series of 68 patients. N Engl J Med. 1990:322:1829-1836.
7.    Walls AWG, Soames JV. Dental manifestations of autoimmune hypoparathyroidism. Oral Surg Oral Med Oral Pathol. 1993;75:452-454.
8.    Perheentupa J. Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. J Clin Endocrinol Metab. 2006;91:2843-2850.
9.    Perniola R, Falorni A, Clemente MG, Forini F, Accogli E, Lobreglio G. Organ-specific and non-organ-specific autoantibodies in children and young adults with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy(APECED). Eur J Endocrinol. 2000;143:497-503.
10.    Gylling M, Tuomi T, Björses P, Kontiainen S, Partanen J, Christie MR, Knip M, Perheentupa J, Miettinen A. ss-cell autoantibodies, human leukocyte antigen II alleles, and type 1 diabetes in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. J Clin Endocrinol Metab. 2000;85:4434-4440.
11.    Zlotogora J, Shapiro MS Polyglandular autoimmune syndrome type I among Iranian Jews. J Med Genet. 1992: 29:824-826.
12.    Rosatelli MC, Meloni A, Meloni A, Devoto M, Cao A, Scott HS, Peterson P, Heino M, Krohn KJ, Nagamine K,Kudoh J, Shimizu N, Antonarakis SE. A common mutation in Sardinian autoimmune polyendocrinopathy-candidiasis- ectodermal dystrophy patients. Hum Genet. 1998:103:428-434.
13.    Finnish-German APECED Consortium. An autoimmune disease, APECED, caused by mutations in a novel gene featuring two PHD-type zinc-finger domains. Nat Genet. 1997;17:399-403.
14.    Nagamine K, Peterson P, Scott HS, Kudoh J, Minoshima S, Heino M, Krohn KJ, Lalioti MD, Mullis PE, Antonarakis SE, Kawasaki K, Asakawa S, Ito F, Shimizu N. Positional cloning of the APECED gene. Nat Genet. 1997:17:393-398.
15.    Dominguez M, Crushell E, Ilmarinen T, McGovern E, Collins S, Chang B, Fleming P, Irvine AD, Brosnahan D,Ulmanen I, Murphy N, Costigan C. Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) in the Irish population. J Pediatr Endocrinol Metab. 2006:19:1343-1352.
16.    Perheentupa J. APS-I/APECED: the clinical disease and therapy. Endocrinol Metab Clin North Am. 2002;31:295-320.
17.    Björses P, Halonen M, Palvimo JJ, Kolmer M, Aaltonen J, Ellonen P, Perheentupa J, Ulmanen I, Peltonen L. Mutations in the AIRE gene: effects on sub-cellular location and transactivation function of the APECED protein. Am J Hum Genet. 2000;66:378-392.
18.    Lankisch TO, Strassburg CP, Debray D, Manns MP, Jacquemin E. Detection of autoimmune regulator gene mutations in children with type 2 autoımmune hepatitis and extrahepatic immune-mediated diseases. J Pediatr. 2005; 146:839-842
19.    Peterson P, Peltonen L. Autoimmune polyendocrinopathy syndrome type 1 (APS1) and AIRE gene: new views on molecular basis of autoimmunity. J Autoimmun. 2005;25(Suppl):49-55.
20.    Halonen M, Eskelin P, Myhre AG, Perheentupa J, Husebye ES, Kämpe O, Rorsman F, Peltonen L, Ulmanen I,Partanen J. AIRE mutations and human leukocyte antigen genotypes as determinants of the autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy phenotype. J Clin Endocrinol Metab. 2002;87:2568-2574.
21.    Halonen M, Kangas H, Rüppell T, Ilmarinen T, Ollila J, Kolmer M, Vihinen M, Palvimo J, Saarela J, Ulmanen I,Eskelin P. APECED-causing mutations in AIRE reveal the functional domains of the protein. Hum Mutat. 2004;23:245-257.
22.    Heino M, Peterson P, Kudoh J, Shimizu N, Antonarakis SE, Scott HS, Krohn K APECED mutations in the autoimmune regulator (AIRE) gene. Hum Mutat. 2001;18:205-211.
23.    Stolarski B, Pronicka E, Korniszewski L, Pollak A, Kostrzewa G, Rowi?ska E, W?odarski P, Skórka A, Gremida M,Krajewski P, Ploski R. Molecular background of polyendocrinopathy–candidiasis– ectodermal dystrophy syndrome in a Polish population: novel AIRE mutations and an estimate of disease prevalence. Clin Genet. 2006;70:348-354.
24.    Vogel A, Strassburg CP, Obermayer-Straub P, Brabant G, Manns MP. The genetic background of autoimmune polyendocrinopathy- candidiasis–ectodermal dystrophy and its autoimmune disease components. J Mol Med (Berl). 2002;80: 201-211.
25.    Kogawa K, Nagafuchi S, Katsuta H, Kudoh J, Tamiya S, Sakai Y, Shimizu N, Harada M. Expression of AIRE gene in peripheral monocyte/ dendritic cell lineage. Immunol Lett. 2002;80:195-198.
26.    Tazi-Ahnini R, Cork MJ, Gawkrodger DJ, Birch MP, Wengraf D, McDonagh AJ, Messenger AG. Role of the autoimmune regulator (AIRE) gene in alopecia areata: strong association of a potentially functional AIRE polymorphism with alopecia universalis. Tissue Antigens. 2002;60:489-495.
27.    Gylling M, Kääriäinen E, Väisänen R, Kerosuo L, Solin ML, Halme L, Saari S, Halonen M, Kämpe O, Perheentupa J, Miettinen A. The hypoparathyroidism of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy protective effect of male sex. J Clin Endocrinol Metab. 2003;88:4602-4608.