The autoimmune regulator gene (AIRE) is strongly associated with vitiligo

Article (PDF Available)inBritish Journal of Dermatology 159(3):591-6 · August 2008with77 Reads
DOI: 10.1111/j.1365-2133.2008.08718.x · Source: PubMed
Abstract
Vitiligo is an autoimmune disorder that occurs with greatly increased frequency in the rare recessive autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) caused by mutations of the autoimmune regulator (AIRE) gene on chromosome 21q22.3. We have previously detected an association between alopecia areata and single nucleotide polymorphisms (SNPs) in the AIRE gene. To report the findings of an extended study including haplotype analysis on six AIRE polymorphisms (AIRE C-103T, C4144G, T5238C, G6528A, T7215C and T11787C) in vitiligo, another APECED-associated disease. A case-control analysis was performed. Results showed a strong association between AIRE 7215C and vitiligo [P = 1.36 x 10(-5), odds ratio (OR) 3.12, 95% confidence interval (CI) 1.87-5.46]. We found no significant association with the other polymorphisms individually. However, haplotype analysis revealed that the AIRE haplotype CCTGCC showed a highly significant association with vitiligo (P = 4.14 x 10(-4), OR 3.00, 95% CI 1.70-5.28). To select the most informative minimal haplotypes, we tagged the polymorphisms using SNP tag software. Using AIRE C-103T, G6528A, T7215C and T11787C as tag SNPs, the haplotype AIRE CGCC was associated with vitiligo (P = 0.003, OR 2.49, 95% CI 1.45-4.26). The link between vitiligo and AIRE raises the possibility that defective skin peripheral antigen selection in the thymus is involved in the changes that result in melanocyte destruction in this disorder.

Figures

CLINICAL AND LABORATORY INVESTIGATIONS BJD British Journal of Dermatology
The autoimmune regulator gene (AIRE) is strongly
associated with vitiligo
R. Tazi-Ahnini,* A.J.G. McDonagh, D.A. Wengraf,* T.R.J. Lovewell,* Y. Vasilopoulos,* A.G. Messenger,
M.J. Cork* and D.J. Gawkrodger
*Division of Genomic Medicine, University of Sheffield, Sheffield S10 2RX, U.K.
Dermatology Immunogenetics Group, University of Sheffield, Royal Hallamshire Hospital, Sheffield S10 2JF, U.K.
Correspondence
R. Tazi-Ahnini.
E-mail: r.taziahnini@sheffield.ac.uk
Accepted for publication
19 November 2007
Key words
AIRE gene, autoimmunity, genetics, vitiligo
Conflicts of interest
None declared.
DOI 10.1111/j.1365-2133.2008.08718.x
Summary
Background Vitiligo is an autoimmune disorder that occurs with greatly increased
frequency in the rare recessive autoimmune polyendocrinopathy–candidiasis–
ectodermal dystrophy syndrome (APECED) caused by mutations of the auto-
immune regulator (AIRE) gene on chromosome 21q22Æ3. We have previously
detected an association between alopecia areata and single nucleotide polymor-
phisms (SNPs) in the AIRE gene.
Objectives To report the findings of an extended study including haplotype analysis
on six AIRE polymorphisms (AIRE C–103T, C4144G, T5238C, G6528A, T7215C
and T11787C) in vitiligo, another APECED-associated disease.
Methods A case–control analysis was performed.
Results Results showed a strong association between AIRE 7215C and vitiligo
[P =1Æ36 · 10
)5
, odds ratio (OR) 3Æ12, 95% confidence interval (CI) 1Æ87–
5Æ46]. We found no significant association with the other polymorphisms indi-
vidually. However, haplotype analysis revealed that the AIRE haplotype CCTGCC
showed a highly significant association with vitiligo (P =4Æ14 · 10
)4
,OR3Æ00,
95% CI 1Æ70–5Æ28). To select the most informative minimal haplotypes, we
tagged the polymorphisms using SNP tag software. Using AIRE C–103T, G6528A,
T7215C and T11787C as tag SNPs, the haplotype AIRE CGCC was associated with
vitiligo (P =0Æ003, OR 2Æ49, 95% CI 1Æ45–4Æ26).
Conclusions The link between vitiligo and AIRE raises the possibility that defective
skin peripheral antigen selection in the thymus is involved in the changes that
result in melanocyte destruction in this disorder.
The causes of vitiligo are poorly understood but there is con-
siderable evidence to support the view that vitiligo is an auto-
immune disease in some patients. Vitiligo is clinically
associated with other conditions thought to be autoimmune in
origin such as diabetes mellitus, pernicious anaemia, thyroid
disease and alopecia areata.
1,2
Thyroid disease is found in about
20% of adults with vitiligo.
3
Patients with vitiligo have elevated
levels of organ-specific antibodies such as thyroid peroxidase
or gastric parietal cell antibodies.
2,4,5
Patients with vitiligo also
have circulating autoantibodies to melanocyte antigens
6
and
show circulating T lymphocytes directed against melanocyte
antigens.
7
Autoimmune phenomena have also been observed in
the animal model of vitiligo, the Smyth line chicken.
8
Vitiligo occurs in the general population with a prevalence
of 1–2% and there is a familial tendency, with 20–30% of
patients reporting a first-degree relative also affected.
3
Spritz
estimates the risk to a patient’s siblings, the genotype relative
risk (k
s
), at 16 times the population prevalence for general-
ized vitiligo.
9
There is strong evidence also from twin studies
indicating the involvement of genetic factors in the pathogen-
esis of vitiligo.
10
Formal segregation analyses of vitiligo have
suggested that three or four major loci contribute to the dis-
ease susceptibility in a complex interactive manner, and poly-
genic inheritance is generally accepted as the model to explain
the familial occurrence of vitiligo.
11,12
However, in the study
by Sun et al.
11
it was suggested that a dominant major gene
was likely. It is also likely that environmental factors intervene
to produce disease expression.
Several candidate genes have been investigated in vitiligo,
including human leucocyte antigen (HLA) class I and class II
genes, transporter associated with antigen processing protein-
1(TAP1) gene, cytotoxic T-lymphocyte-associated-protein-4
(CTLA4) gene, angiotensin-converting enzyme (ACE) gene, the
catalase (CAT) gene and the NLRP1 (previously known as
2008 The Authors
Journal Compilation 2008 British Association of Dermatologists British Journal of Dermatology 2008 1
NALP1) gene encoding NACHT leucine-rich-repeat protein 1.
Strong association has been reported between a single nucleo-
tide polymorphism (SNP) in exon 9 of CAT and vitiligo.
13
Sig-
nificant association has been found between polymorphisms
in the ACE gene
14
in Korean patients but not in British
patients.
15
An association between CTLA4 genetic variants and
vitiligo was detected only for vitiligo occurring with other
autoimmune diseases.
16
Several groups have performed genetic
analysis of HLA class I and class II genes in vitiligo. A micro-
satellite analysis supported association between vitiligo and
HLA-A2, A31, B13, B27, B56, B60, Cw6, DR4, DR5, DR7,
DR53 and DQ3 (DQB1*0303) and a negative association with
HLA-A9, A24, B35, B52, Cw7 and DQA1*0501.
17
An associa-
tion of the TAP1 gene and vitiligo suggests a possible role for
the major histocompatibility complex class I antigen process-
ing and or presentation pathway in the antimelanocyte auto-
immune response involved in vitiligo pathogenesis.
18
Jin et al.
have recently demonstrated association of vitiligo with NLRP1
that encodes NACHT, a gene involved in regulation of the
innate immune response.
19
Mutations in the autoimmune regulator (AIRE) gene, located
on chromosome 21q22Æ3, cause the rare recessive autoim-
mune polyendocrinopathy–candidiasis–ectodermal dystrophy
syndrome (APECED). APECED is characterized by autoimmuni-
ty directed against endocrine and other organs including the
hair follicle. Vitiligo in patients with APECED is more than 10
times commoner than in the general population
20
but there
are no published data on the frequency of vitiligo in heterozy-
gous carriers of the APECED AIRE mutations. The gene prod-
uct, Aire, is believed to determine thymic stromal cell
organization and self-tolerance during T-cell maturation. The
AIRE gene is expressed in several tissues including the thymus,
lung, spleen, lymph nodes, ovary, testis, kidney and adrenal
gland. AIRE mRNA is also weakly detected in peripheral blood
leucocytes but thymic AIRE expression is at least 10 times
higher than in other tissues.
21
These patterns of expression
suggest that Aire protein has an important role in the immune
system. In addition, AIRE-deficient mice are incapable of delet-
ing autoreactive T cells in the thymus, resulting in breakdown
of tolerance mechanisms in organs such as the parathyroid,
adrenal glands and hair follicles.
22
The 545 amino acid Aire
protein contains several structural motifs suggestive of tran-
scriptional activity. Evidence from a mouse knockout model
suggests that the level of AIRE expression is pivotal in regulat-
ing a number of genes that could be directly involved in the
pathogenesis of APECED-associated diseases including viti-
ligo.
23
In this study, we have analysed the distribution of six
AIRE polymorphisms in 86 patients with vitiligo and a large
number of matched controls.
Materials and methods
Patients and controls
Eighty-six patients with vitiligo were recruited from dermatol-
ogy clinics in Sheffield, South Yorkshire, U.K. Three hundred
and sixty-three healthy controls were taken from donated
blood from the Trent Blood Transfusion Service. The patients
were ethnically matched (Caucasian, North England), and age
ranges were comparable. The patients were all diagnosed and
followed up by consultant dermatologists. Clinical information
acquired from the patients included the age at onset, presence
of other autoimmune diseases and family history of vitiligo
(
Table 1).
Power calculation
The power of the study was assessed using Quanto software
(http://hydra.usc.edu/GxE/). Under a dominant inheritance
model for the AIRE 7215 variant, 86 patients with two
unmatched controls per patient gives 97% power to detect
association (P <0Æ007).
Polymorphism detection methods
Genomic DNA was extracted from whole blood using
standard protocols and stored at 0Æ1 lg lL
)1
. Polymerase
chain reaction (PCR) for the promoter region was per-
formed in nine individuals. The appropriate bands were
purified from the gel by centrifugation through columns of
glass wool treated with dimethyldichlorosilane and chloro-
form, followed by ethanol precipitation of the products of
the centrifugation. The DNA thus obtained was sequenced
on an ABI 373 automatic sequencer (Applied Biosystems,
Foster City, CA, U.S.A.), and the sequences aligned against
the published sequence to detect polymorphisms, using the
CristalW 1Æ8 alignment program
24
and the Boxshade viewer.
The AIRE C4144G, T5238C, G6528A, T7215C and T11787C
polymorphisms were selected from SNPs detected in our
previous study based on the nature of the SNP and the
frequency of the rare allele.
25
The AIRE C–103T polymor-
phism in the promoter region was newly identified by
direct sequencing of the first 600 bp using purified PCR
products.
Table 1 Sex, age at onset and associated diseases in patients with
vitiligo
Overall patient group
Sex M 31, F 55
Family history of vitiligo 17
Mean age at onset of vitiligo (years) 30Æ8
Patients with associated autoimmune disease
Sex M 4, F 9
Family history of vitiligo 5
Mean age at onset of vitiligo (years) 33Æ4
Thyroid disease 5
Diabetes mellitus 5
Halo naevus 5
Alopecia areata 4
Addison’s disease 1
Pernicious anaemia 1
2008 The Authors
Journal Compilation 2008 British Association of Dermatologists British Journal of Dermatology 2008
2 AIRE haplotypes in vitiligo, R. Tazi-Ahnini et al.
Genotyping
PCR–restriction fragment length polymorphism analysis was
used for allelic discrimination. DNA from patients and controls
was amplified by PCR in 25-lL reactions, and 20 lL of the
products of these reactions was digested in a 25-lL reaction.
The digests contained 2Æ5 units of the enzyme with 2Æ5 lLof
the supplied buffer (New England Biolabs, Beverly, MA,
U.S.A.). PCR products were digested with EcoNI, Fnu4HI NlaIV,
MluI, MscI, HaeIII and NcoI to discriminate alleles of the C–
103T, C4144G, T5238C, G6528A, T7215C and T11787C
polymorphisms, respectively. Two assays were used for the
AIRE C4144G SNP, an Fnu4HI assay that digested the common
allele, and an NlaIV, which digested the rare allele. For the
T11787C polymorphism we used a modified primer which
changed the G at position +11787 to a C. For all the SNPs,
the enzyme cuts both alleles at least once, minimizing the risk
of genotyping errors compared with only a single digestion.
All samples were digested overnight as recommended in the
manufacturer’s instructions and the digest products separated
by agarose gel electrophoresis. The AIRE gene occupies
11Æ9 kb and our selected SNPs encompass the region from
position –103 to +11787. Taking into account the fact that
only one of the SNPs is in complete linkage disequilibrium
(LD) with all the others (
Fig. 1), this panel provides good
coverage of the gene.
Statistical analysis
As the purpose of this study was to investigate the effect of
the risk allele of the investigated SNPs on the association of
the AIRE gene with vitiligo, the heterozygous individuals and
those homozygous for the rare allele were grouped together,
and their risk compared with the individuals homozygous
for the common allele, using 2 · 2 tables to perform case–
control tests and calculate risk ratios. The assumption of a
dominant model for the calculation is based on recent analy-
sis in a large family study from Southern China.
11
The data
were also analysed using the cocaphase procedure of the
Unphased package (http://www.mrc-bsu.cam.ac.uk/personal/
frank/software/unphased/) to provide a suitable correction
for multiple testing in the context of linked SNPs.
The PMPLUS program
26
was used to compare frequencies
of 338 and 150 haplotypes generated from controls and cases,
respectively, using the EM algorithm to estimate haplotype fre-
quencies, and providing a v
2
value for haplotype association
with disease. The program was then used to identify haplo-
types that appeared with a frequency greater than 0Æ05, and
v
2
tests used to detect any association between vitiligo and
these haplotypes.
LD between all pairs of SNPs was calculated using Haploview
software
27
(http://www.broad.mit.edu/mpg/haploview/).
Results
To characterize the association between the AIRE gene and viti-
ligo, we selected five SNPs from our previous study on alope-
cia areata
25
on the basis of their frequency and potential
functional relevance. These were the nonsynonymous C4144G
and T5238C, the silent mutations T7215C and T11787C, and
the intronic SNP G6528A. A sixth SNP, C–103T in the pro-
moter region, was newly identified by direct sequencing. The
allelic distribution of these six markers was assessed in vitiligo
and control samples (
Table 2). None of the six showed signif-
icant deviation from Hardy–Weinberg equilibrium. A test for
carriage of the rare allele was used for all the loci. Positive
associations of the polymorphisms AIRE C4144G (previously
described as 961G) and AIRE G6528A with vitiligo became
nonsignificant on correction for multiple testing. There was a
strong association between the AIRE 7215C allele and vitiligo
[P =1Æ36 · 10
)5
, odds ratio (OR) 3Æ12, 95% confidence
interval (CI) 1Æ87–5Æ46]. We found no significant association
of disease with AIRE –103, 5238 or 11787. A stratified analy-
sis also showed a significant association with AIRE 11787
confined to patients with associated autoimmune disease
(P =0Æ0009).
To assess LD between the six markers, standardized coeffi-
cients of disequilibrium (D¢) between all pairs of SNPs were
calculated (Fig. 1). AIRE 5238 was in complete LD with the
other five markers, suggesting that this is a newly incorpo-
rated genetic variation in the Caucasian population.
28
In con-
trast, AIRE 4144 was in complete LD with only one of the
other markers, AIRE 5238. Interestingly, AIRE 7215 was in
strong LD with AIRE 11787 and in complete LD with AIRE
5238 and –103 (Fig. 1). In order to define the association
between these AIRE genetic variants and vitiligo clearly, haplo-
types were reconstructed using the PMPLUS program and their
Fig 1. Haploview output showing pairwise coefficients of
disequilibrium (D¢ values) for the AIRE SNPs at positions –103, 4144,
5238, 6528, 7215 and 11787, respectively. D¢ values are not shown
where there is complete linkage disequilibrium.
2008 The Authors
Journal Compilation 2008 British Association of Dermatologists British Journal of Dermatology 2008
AIRE haplotypes in vitiligo, R. Tazi-Ahnini et al. 3
frequencies compared between cases and controls (Table 3).
The AIRE haplotype CCTGCC showed a highly significant asso-
ciation with vitiligo (P =4Æ14 · 10
)4
,OR3Æ00, 95% CI
1Æ70–5Æ28, Table 3).
To reduce the number of estimated haplotypes for analysis
we tagged the SNPs in order to select those which were most
informative,
29
using the online resource at http://www.well.
ox.ac.uk/~xiayi/haplotype/index.html. With AIRE C–103T,
G6528A, T7215C and T11787C as tag SNPs, we re-analysed
the haplotype distribution in cases and controls (
Table 4). The
AIRE haplotype CGCC was associated with disease (P =0Æ003,
OR 2Æ49, 95% CI 1Æ45–4Æ26).
Discussion
APECED is an autoimmune disorder caused by mutations in
the AIRE gene. Vitiligo in APECED is more than 10 times com-
moner than in the general population. In this study, haplotype
Table 2 Allelic distribution of AIRE polymorphisms at positions –103, 4144, 5238, 6528, 7215 and 11787 in cases (V) and controls (C). Call
rate, odds ratio (OR), 95% confidence interval (CI) and P-value are shown for each variant
SNP
Common
homo Hetero
Rare
homo
Call
rate
Freq
(rare) OR (95% CI) P-value
C–103T (C) 155 43 1 92Æ10Æ11 1Æ76 (0Æ94–3Æ32) 0Æ604
C–103T (V) 60 20 0 93Æ10Æ13
C4144G (C) 303 57 4 96Æ30Æ09 1Æ79 (1Æ02–3Æ14) 0Æ039
C4144G (V) 61 22 0 96Æ60Æ13
T5238C (C) 262 4 0 100 0Æ01 0Æ79 (0Æ09–7Æ16) 0Æ258
T5238C (V) 84 0 0 97Æ70Æ00
G6528A (C) 162 30 3 95Æ80Æ09 3Æ00 (1Æ09–3Æ66) 0Æ023
G6528A (V) 59 24 0 96Æ60Æ15
T7215C (C) 150 47 1 96Æ50Æ12 3Æ12 (1Æ87–5Æ46) 1Æ36
· 10
)5
T7215C (V) 42 35 8 98Æ80Æ30
T11787C (C) 65 86 34 95Æ50Æ42 0Æ83 (0Æ48–1Æ43) 0Æ508
T11787C (V) 30 35 11 88Æ50Æ38
SNP, single nucleotide polymorphism.
Table 3 P-values for case–control analysis on AIRE C–103T, C4144G, T5238C, G6528A, T7215C and T11787C haplotypes. Susceptibility
haplotypes with significant association are shown in bold and haplotypes with negative association underlined
Controls Freq Cases Freq v
2
P
c
OR (95% CI)
CCTGTT 133 0Æ393 52 0Æ346 0Æ97 1Æ626 0Æ82 (0Æ55–1Æ22)
CCTGTC 84 0Æ248 17 0Æ112 11Æ57 0Æ003 0Æ39 (0Æ22–0Æ68)
CCTGCC 26 0Æ078 30 0Æ197 15Æ49 4Æ14 · 10
)4
3Æ00 (1Æ70–5Æ28)
CCTATT 22 0Æ064 4 0Æ027 3Æ04 0Æ406 0Æ39 (0Æ13–1Æ16)
TCTGTT 37 0Æ109 16 0Æ109 0Æ01 4Æ644 0Æ97 (0Æ52–1Æ81)
Remainder 36 0Æ107 31 0Æ208
Total 338 1Æ000 150 1Æ000
P
c
, corrected P-value; OR, odds ratio; CI, confidence interval.
Table 4 P-values for case–control analysis on AIRE C–103T, G6528A, T7215C and T11787C haplotypes. Susceptibility haplotypes with significant
association are shown in bold and haplotypes with negative association underlined
All patients Controls Freq Cases Freq v
2
P
c
OR (95% CI)
CGTT 136 0Æ404 55 0Æ364 0Æ56 2Æ279 0Æ86 (0Æ58–1Æ28)
CGTC 96 0Æ283 18 0Æ119 15Æ61 3Æ88 · 10
)4
0Æ34 (0Æ20–0Æ59)
CGCC 32 0Æ096 31 0Æ204 11Æ60 0Æ003 2Æ49 (1Æ45–4Æ26)
CATT 20 0Æ060 11 0Æ072 0Æ35 2Æ771 1Æ26 (0Æ59–2Æ70)
TGTT 39 0Æ115 18 0Æ122 0Æ02 4Æ424 1Æ05 (0Æ58–1Æ90)
Remainder 12 0Æ036 18 0Æ119
Total 338 1Æ000 150 1Æ000
P
c
, corrected P-value; OR, odds ratio; CI, confidence interval.
2008 The Authors
Journal Compilation 2008 British Association of Dermatologists British Journal of Dermatology 2008
4 AIRE haplotypes in vitiligo, R. Tazi-Ahnini et al.
analysis showed that AIRE –103C, 4144C, 5238T, 6528G,
7215C, 11787C (CCTGCC) has the strongest association with
disease. Although the present analysis is based on a small
group of patients with vitiligo and requires replication in lar-
ger studies, we have previously shown that AIRE C4144G is
associated with alopecia areata, another APECED-associated
disease.
25
Haplotype analysis has shown that AIRE CCTGCC is
also associated with alopecia areata (unpublished data), sug-
gesting that AIRE is a common factor involved in the patho-
genesis of both these autoimmune disorders. SNP tag
haplotype analysis has shown that the AIRE protective haplo-
types differ from susceptibility haplotypes by only two bases,
AIRE T7215C and C11787T. The association between AIRE
T7215C and vitiligo is stronger than that with C11787T and
the latter may be accounted for by LD (LD between AIRE
T7215C and C11787T is strong; D¢ =0Æ78).
AIRE T7215C is a synonymous substitution and until recent-
ly it was widely accepted that synonymous mutations are
selectively neutral and without an effect in gene expression
and or mRNA translation. However, this has proven to be
incorrect as a synonymous mutation that could cause the for-
mation of helices would stabilize the mRNA, thereby increas-
ing its resistance to degradation and or modification.
30
An
example of such a mechanism is a synonymous mutation in
the dopamine receptor D2 (DRD2), which is responsible for an
alteration in the predicted mRNA structure and causes a
decrease in mRNA stability and translation, suggesting that it
could play a key role in the regulation of DRD2 gene expres-
sion.
31
More recently, a silent SNP in the multidrug resistance
1(MDR1) gene (now known as ABCB1) has been reported to
change drug and inhibition interactions, suggesting that this
synonymous polymorphism may affect cotranslational folding
of the protein.
32
This appears also to be the case with the corneodesmosin
gene, where a synonymous mutation located in an RNA stabil-
ity motif leads to increased stability of the RNA transcript by
diminishing the transcript affinity for a 39-kDa RNA binding
protein.
33
Our in silico analysis of the folding of the AIRE RNA
structure shows that the highly associated haplotype AIRE
CGCC gives the most stable mRNA secondary structure, sug-
gesting that AIRE CGCC mRNA could have a longer half-life
and produce more Aire protein, leading to dysregulation of
downstream genes (data not shown).
The association of vitiligo with other autoimmune diseases
such as diabetes mellitus, pernicious anaemia, thyroid disease
and alopecia areata, and the presence of circulating autoanti-
bodies to melanocyte antigens
6
and circulating T lymphocytes
directed against melanocyte antigens
7
in patients with vitiligo
support strongly the involvement of immunological factors in
the pathogenesis. The establishment of a link between vitiligo
and AIRE strengthens this hypothesis. As Aire is a transcription
regulator which controls the expression of many peripheral
antigens in the thymus,
34
it is reasonable to hypothesize that
in the case of vitiligo there is defective selection of skin
peripheral antigens by Aire in the thymus. Alternatively, AIRE
alleles could be associated with the level of AIRE expression in
the thymus, with concomitant effects on the selection of skin
peripheral antigens which could predispose to development of
the disease.
References
1 Cunliffe WJ, Hall R, Newell DJ, Stevenson CJ. Vitiligo, thyroid dis-
ease and autoimmunity. Br J Dermatol 1968; 80:135–9.
2 Zauli D, Tosti A, Biasco G et al. Prevalence of autoimmune atrophic
gastritis in vitiligo. Digestion 1986; 34:169–72.
3 Mason CP, Gawkrodger DJ. Vitiligo presentation in adults. Clin Exp
Dermatol 2005; 30:344–5.
4 Brostoff J. Autoantibodies in patients with vitiligo. Lancet 1969;
ii:177–8.
5 Betterle C, Del Prete GF, Peserico A et al. Autoantibodies in vitiligo.
Arch Dermatol 1976; 112:1328.
6 Kemp EH, Gawkrodger DJ, MacNeil S et al. Detection of tyrosinase
autoantibodies in patients with vitiligo using 35S-labeled recombi-
nant human tyrosinase in a radioimmunoassay. J Invest Dermatol
1997; 109:69–73.
7 Ogg GS, Rod DP, Romero P et al. High frequency of skin-homing
melanocyte-specific cytotoxic T lymphocytes in autoimmune
vitiligo. J Exp Med 1998; 188:1203–8.
8 Searle EA, Austin LM, Boissy YL et al. Smyth chicken melanocyte
autoantibodies: cross-species recognition, in vivo binding, and
plasma membrane reactivity of the antiserum. Pigment Cell Res 1993;
6:145–57.
9 Spritz RA. The genetics of generalized vitiligo and associated auto-
immune diseases. Pigment Cell Res 2007; 20:271–8.
10 Alkhateeb A, Fain PR, Thody A et al. Epidemiology of vitiligo and
associated autoimmune diseases in Caucasian probands and their
families. Pigment Cell Res 2003; 16:208–14.
11 Sun X, Xu A, Wei X et al. Genetic epidemiology of vitiligo: a study
of 815 probands and their families from south China. Int J Dermatol
2006; 45:1176–81.
12 Zhang XJ, Liu JB, Gui JP et al. Characteristics of genetic epidemiol-
ogy and genetic models for vitiligo. J Am Acad Dermatol 2004;
51:383–90.
13 Casp CB, She JX, McCormack WT. Genetic association of the cata-
lase gene (CAT) with vitiligo susceptibility. Pigment Cell Res 2002;
15:62–6.
14 Jin SY, Park HH, Li GZ
et al. Association of angiotensin converting
enzyme gene I D polymorphism of vitiligo in Korean population.
Pigment Cell Res 2004; 17:84–6.
15 Akhtar S, Gavalas NG, Gawkrodger DJ et al. An insertion deletion
polymorphism in the gene encoding angiotensin converting
enzyme is not associated with generalised vitiligo in an English
population. Arch Dermatol Res 2005; 297:94–8.
16 Blomhoff A, Kemp EH, Gawkrodger DJ et al. CTLA4 polymorphisms
are associated with vitiligo, in patients with concomitant auto-
immune diseases. Pigment Cell Res 2005; 18:55–8.
17 Arcos-Burgos M, Parodi E, Salgar M et al. Vitiligo: complex segrega-
tion and linkage disequilibrium analyses with respect to microsatel-
lite loci spanning the HLA. Hum Genet 2002; 110:334–42.
18 Casp CB, She JX, McCormack WT. Genes of the LMP TAP cluster
are associated with the human autoimmune disease vitiligo. Genes
Immun 2003; 4:492–9.
19 Jin Y, Mailloux CM, Gowan K et al. NALP1 in vitiligo-associated
multiple autoimmune disease. N Engl J Med 2007; 356:1216–25.
20 Ahonen P, Myllarniemi S, Sipila I, Perheentupa J. Clinical variation
of autoimmune polyendocrinopathy–candidiasis–ectodermal dys-
trophy (APECED) in a series of 68 patients. N Engl J Med 1990;
322:1829–36.
2008 The Authors
Journal Compilation 2008 British Association of Dermatologists British Journal of Dermatology 2008
AIRE haplotypes in vitiligo, R. Tazi-Ahnini et al. 5
21 Ruan QG, Wang CY, Shi JD, She JX. Expression and alternative
splicing of the mouse autoimmune regulator gene (Aire). J Auto-
immun 1999; 13:307–13.
22 Ramsey C, Winqvist O, Puhakka L et al. Aire deficient mice develop
multiple features of APECED phenotype and show altered immune
response. Hum Mol Genet 2002; 11:397–409.
23 Anderson MS, Venanzi ES, Klein L et al. Projection of an immuno-
logical self shadow within the thymus by the aire protein. Science
2002; 298:1395–401.
24 Chenna R, Sugawara H, Koike T et al. Multiple sequence alignment
with the Clustal series of programs. Nucleic Acids Res 2003;
31:3497–500.
25 Tazi-Ahnini R, Cork MJ, Gawkrodger DJ et al. Role of the auto-
immune regulator (AIRE) gene in alopecia areata: strong association
of a potentially functional AIRE polymorphism with alopecia
universalis. Tissue Antigens 2002; 60:489–95.
26 Zhao JH, Curtis D, Sham PC. Model-free analysis and permutation
tests for allelic associations. Hum Hered 2000; 50:133–9.
27 Barrett JC, Fry B, Maller J, Daly MJ. Haploview: analysis and visual-
ization of LD and haplotype maps. Bioinformatics 2005; 21:263–5.
28 Polanska J, Kimmel M. A simple model of linkage disequilibrium
and genetic drift in human genomic SNPs: importance of demo-
graphy and SNP age. Hum Hered 2005; 60:181–95.
29 Ke X, Cardon LR. Efficient selective screening of haplotype tag
SNPs. Bioinformatics 2003; 19:287–8.
30 Chen Y, Carlini DB, Baines JF et al. RNA secondary structure and
compensatory evolution. Genes Genet Syst 1999; 74:271–86.
31 Duan J, Wainwright MS, Comeron JM et al. Synonymous mutations
in the human dopamine receptor D2 (DRD2) affect mRNA stability
and synthesis of the receptor. Hum Mol Genet 2003; 12:205–16.
32 Kimchi-Sarfaty C, Oh JM, Kim IW et al. A ‘silent’ polymorphism in
the MDR1 gene changes substrate specificity. Science 2007; 315:525–
8.
33 Capon F, Allen MH, Ameen M et al. A synonymous SNP of the cor-
neodesmosin gene leads to increased mRNA stability and demon-
strates association with psoriasis across diverse ethnic groups.
Hum Mol Genet 2004; 13:2361–8.
34 Ruan QG, Tung K, Eisenman D et al. The autoimmune regulator
directly controls the expression of genes critical for thymic epithe-
lial function. J Immunol 2007; 178:7173–80.
2008 The Authors
Journal Compilation 2008 British Association of Dermatologists British Journal of Dermatology 2008
6 AIRE haplotypes in vitiligo, R. Tazi-Ahnini et al.
    • "Hence, potentially auto-reactive T cell clones specific for several auto-antigens, including melanoma antigens (MA) such as MAGE [6, 10, 11], are exported to the periphery. AIRE gene is polymorphic and its polymorphisms may be associated to disease susceptibility [12][13][14]. Recently we observed that reciprocal variant alleles of AIRE single nucleotide polymorphisms (SNPs) rs1055311, rs1800520 and rs1800522 are differently present in healthy subjects and in melanoma patients [15]. "
    [Show abstract] [Hide abstract] ABSTRACT: AIRE is involved in susceptibility to melanoma perhaps regulating T cell immunity against melanoma antigens (MA). To address this issue, AIRE and MAGEB2 expressions were measured by real time PCR in medullary thymic epithelial cells (mTECs) from two strains of C57BL/6 mice bearing either T or C allelic variant of the rs1800522 AIRE SNP. Moreover, the extent of apoptosis induced by mTECs in MAGEB2-specific T cells and the susceptibility to in vivo melanoma B16F10 cell challenge were compared in the two mouse strains.The C allelic variant, protective in humans against melanoma, induced lower AIRE and MAGEB2 expression in C57BL/6 mouse mTECs than the T allele. Moreover, mTECs expressing the C allelic variant induced lower extent of apoptosis in MAGEB2-specific syngeneic T cells than mTECs bearing the T allelic variant (p < 0.05). Vaccination against MAGEB2 induced higher frequency of MAGEB2-specific CTL and exerted higher protective effect against melanoma development in mice bearing the CC AIRE genotype than in those bearing the TT one (p < 0.05). These findings show that allelic variants of one AIRE SNP may differentially shape the MA-specific T cell repertoire potentially influencing susceptibility to melanoma.
    Full-text · Article · Aug 2016
    • "In patients with APECED vitiligo is over ten-fold more common than in the general population [25]. AIRE SNP rs1800521 (A399A) was initially reported to be significantly associated with vitiligo by the same group that reported an association of this SNP to AA [26]. However, another independent study that analyzed eight tagSNPs covering all common variants in the AIRE genomic region did not detect any significant association [27] . "
    [Show abstract] [Hide abstract] ABSTRACT: Autoimmune Regulator (AIRE) is a transcriptional regulator that is crucial for establishing central tolerance as illustrated by the Mendelian Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED) syndrome associated with AIRE-inactivating recessive or dominant mutations. Polymorphisms in AIRE have been proposed to be implicated in genetic susceptibility to non-Mendelian organ specific autoimmune diseases. Because there is evidence that in predisposition to Graves’ disease (GD) central tolerance is crucial, we investigated whether AIRE polymorphisms could modulate risk of GD. A case-control association study using 29 variants and conducted in 150 GD patients and 200 controls did not detect any significant association. This result is not exceptional: a systematic review of the literature, including GWAS, on the association of AIRE variants with organ specific autoimmune diseases did not show clear associations; similarly heterozygous recessive mutations are not associated to non-Mendelian autoimmunity. Dominant negative mutations of AIRE are associated to autoimmunity but as mild forms of APECED rather than to non-Mendelian organ specific autoimmunity. The lack of association of common AIRE polymorphisms with polygenic autoimmune diseases is counterintuitive as many other genes less relevant for immunological tolerance have been found to be associated. These findings give rise to the intriguing possibility that evolution has excluded functionally modifying polymorphisms in AIRE.
    Article · Jun 2016
    • "This therefore suggests that the different -230Y alleles affect AIRE expression by influencing the binding of biochemical factors via changes to consensus DNA binding sequence rather than via methylation status of the promoter. These findings are in keeping with our previously identified genetic association between polymorphisms in the AIRE gene and susceptibility to alopecia areata and vitiligo, another autoimmune disorder associated with APS-1 [10, 18, 19]. More recently, a polymorphism in AIRE has been found to be a determinant for predisposition to rheumatoid arthritis in the Japanese population [20] . "
    [Show abstract] [Hide abstract] ABSTRACT: Background: The autoimmune regulator (AIRE) is expressed in the thymus, particularly in thymic medullary epithelial cells (mTECs), and is required for the ectopic expression of a diverse range of peripheral tissue antigens by mTECs, facilitating their ability to perform negative selection of auto-reactive immature T-cells. The expression profile of peripheral tissue antigens is affected not only by AIRE deficiency but also with variation of AIRE activity in the thymus. Method and results: Therefore we screened 591bp upstream of the AIRE transcription start site including AIRE minimal promoter for single nucleotide polymorphism (SNPs) and identified two SNPs -655R (rs117557896) and -230Y (rs751032) respectively. To study the effect of these variations on AIRE promoter activity we generated a Flp-In host cell line which was stably transfected with a single copy of the reporter vector. Relative promoter activity was estimated by comparing the luciferase specific activity for lysates of the different reporter AIRE promoter-reporter gene constructs including AIRE-655G AIRE-230C, AIRE-655G AIRE-230T and AIRE-655A AIRE-230C. The analysis showed that the commonest haplotype AIRE-655G AIRE-230C has the highest luciferase specific activity (p<0.001). Whereas AIRE-655G AIRE-230T has a luciferase specific activity value that approaches null. Both AIRE promoter polymorphic sites have one allele that forms a CpG methylation site which we determined can be methylated in methylation assays using the M.SssI CpG methyltransferase. Conclusion: AIRE-230Y is in a conserved region of the promoter and is adjacent to a predicted WT1 transcription factor binding site, suggesting that AIRE-230Y affects AIRE expression by influencing the binding of biochemical factors to this region. Our findings show that AIRE-655GAIRE-230T haplotype could dramatically alter AIRE transcription and so have an effect on the process of negative selection and affect susceptibility to autoimmune conditions.
    Full-text · Article · May 2015
Show more