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Part 2 - Twin Studies
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J Invest Dermatol. 2000 Dec;115(6):990-3
Concordance of dermatitis herpetiformis and celiac disease in monozygous
twins.
Hervonen K, Karell K, Holopainen P, Collin P, Partanen J, Reunala T.
Department of Dermatology, University Hospital of Tampere, Tampere, Finland.
Celiac disease can be defined as the classical manifestation of gluten
sensitivity, which primarily affects the small intestine. Gluten
sensitivity has also a skin manifestation, i.e., dermatitis herpetiformis.
Both diseases have a strong genetic association with HLA DQ on chromosome
6. In this study we tried to estimate how much different clinical
expressions of gluten sensitivity are determined by genetic factors, and
hence how feasible they are for genetic mapping; therefore, we studied all
six monozygous twin pairs found among 1292 prospectively collected patients
of dermatitis herpetiformis in Finland. Three of the six twin pairs were
concordant for dermatitis herpetiformis and for simultaneous enteropathy,
celiac disease. Two other twin pairs were partially discordant, one of each
pair had dermatitis herpetiformis and celiac disease, whereas the other had
solely the gut manifestation of gluten sensitivity, i.e., celiac disease.
Only one pair was found to be discordant for gluten sensitivity. All the
pairs had typical risk alleles for gluten sensitivity, i.e., either HLA DQ2
or DQ8. These results demonstrate that the genetic component in gluten
sensitivity as broadly defined is very strong (5/6 concordant). Genetically
identical individuals can have clearly distinguished phenotypes, either
dermatitis herpetiformis or celiac disease, suggesting that environmental
factors determine the exact phenotype of this multifactorial disease. These
findings are of importance in genetic linkage analyses, which focus to only
certain phenotypic properties of a complex trait.
Publication Types:
Twin Study
PMID: 11121131 [PubMed - indexed for MEDLINE]
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Am J Gastroenterol. 2000 Jun;95(6):1503-5
Gluten sensitivity in monozygous twins: a long-term follow-up of five pairs.
Bardella MT, Fredella C, Prampolini L, Marino R, Conte D, Giunta AM.
Cattedra di Gastroenterologia, IRCCS Ospedale Maggiore, and Clinica
Pediatrica II, Universita degli Studi, Milan, Italy.
OBJECTIVE: The aim of this study was to investigate the role of genetic
factors and the characteristics of five monozygous twin pairs with at least
one member affected by gluten sensitivity. METHODS: Five pairs of
monozygous female twins, of whom one or both were affected by gluten
sensitivity (i.e., celiac disease or dermatitis herpetiformis), were
followed-up for 11-23 yr. RESULTS: Three pairs were concordant for celiac
disease: the onset was comparable and synchronous in two pairs; in the
third, one member presented an overt malabsorption syndrome, and the other
developed iron deficiency anemia 10 yr later. Discordance for gluten
sensitivity was found in the remaining two pairs, one of whose members was
diagnosed as having, respectively, celiac disease and dermatitis
herpetiformis. CONCLUSIONS: As no environmental factors were found to
affect the phenotypic expression of the disease, genetic factors seem to
play a major role. The presence of overt or latent celiac disease in three
of the four siblings of the three concordant twins, and the association
with cystic fibrosis in all three siblings of one of these families,
further supports this hypothesis.
PMID: 10894587 [PubMed - indexed for MEDLINE]
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Gastroenterology. 2003 Jun;124(7):1767-73
Inflammatory bowel disease in a Swedish twin cohort: a long-term follow-up
of concordance and clinical characteristics.
Halfvarson J, Bodin L, Tysk C, Lindberg E, Jarnerot G.
Division of Gastroenterology, Department of Medicine, Orebro University
Hospital, S-701 85 Orebro, Sweden. [log in to unmask]
BACKGROUND & AIMS: In 1988, we reported the first twin study in
inflammatory bowel disease. The aim of the current study was to follow up
these twins regarding new cases of inflammatory bowel disease and Crohn's
disease characteristics using the Vienna classification. METHODS: The
official Swedish population register and the cause of death register were
used to search for the twins. All living patients were interviewed.
RESULTS: Three monozygotic twins earlier classified as healthy had been
diagnosed with inflammatory bowel disease (ulcerative colitis, n = 2;
Crohn's disease, n = 1). Retrospectively, all 3 were symptomatic at the
original survey. This changed the pair concordance in monozygotic twins
from 6.3% to 18.8% in ulcerative colitis and from 44.4% to 50.0% in Crohn's
disease. A high degree of concordance regarding age at diagnosis, disease
location at diagnosis and during the course, and disease behavior was found
in concordant monozygotic twin pairs with Crohn's disease. Seven of 9 pairs
were identical in 3 or more of these disease characteristics compared with
an expected number of 1.5 (P = 0.000076). CONCLUSIONS: This study confirms
that the genetic influence is stronger in Crohn's disease than in
ulcerative colitis. A remarkable phenotype similarity within concordant
pairs with Crohn's disease was found using the Vienna classification.
Publication Types:
Twin Study
PMID: 12806610 [PubMed - indexed for MEDLINE]
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Scand J Gastroenterol. 2000 Oct;35(10):1075-81
Concordance of inflammatory bowel disease among Danish twins. Results of a
nationwide study.
Orholm M, Binder V, Sorensen TI, Rasmussen LP, Kyvik KO.
Dept. of Internal Medicine, Elsinore Hospital, Denmark.
BACKGROUND: Previous studies have shown an increased risk of inflammatory
bowel disease (IBD) among relatives of patients with Crohn disease and
ulcerative colitis. In the present study the probandwise concordance rates
for ulcerative colitis and Crohn disease among mono- and dizygotic twins
were estimated. Further we aimed to evaluate whether smoking habits might
influence the concordance, and to look for clinical characteristics of
concordant versus discordant twin pairs. METHODS: Among the 38,507
identified twins born in Denmark from 1953 to 1982, a questionnaire was
sent to the 34,076 who previously had accepted to participate in studies.
For twins reporting IBD, the diagnosis was verified by applying standard
criteria to records requested from hospitals or practitioners. RESULTS:
Among the 29,421 (86.3%) twins answering the questionnaire, 103 pairs had
at least one twin who suffered from IBD. In the Crohn disease group five of
10 monozygotic pairs, but none of 27 dizygotic pairs were concordant. In
the ulcerative colitis group three of 21 monozygotic, and two of 44
dizygotic pairs were concordant. The probandwise concordance rate among
monozygotic pairs was 58.3% for Crohn disease and 18.2% for ulcerative
colitis; among the dizygotic pairs the rates were 0 and 4.5%, respectively.
The frequency of smokers was higher among twins with Crohn disease and
lower among twins with ulcerative colitis compared to the frequency in the
twin register. Furthermore, smoking habits were found to be of significance
for discordance for disease. Regarding the clinical characteristics no
homogenous pattern was observed within the concordant pairs and the
differences between concordant and discordant pairs were not significant.
CONCLUSION: The observation of a significantly higher concordance rate
among monozygotic than among dizygotic twin pairs strongly points to a
genetic influence on occurrence of IBD, which seems to be more pronounced
with regard to Crohn disease than to ulcerative colitis. Differences in
smoking habits among the members of the discordant twin pairs may influence
the discordance.
PMID: 11099061 [PubMed - indexed for MEDLINE]
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