Dr Julian Shield
Shield et al.
Is disomic homozygosity at the APECED locus the cause of increased autoimmunity
in Down's syndrome? [Arch.Dis.Ch 1999;81:147-150]
Their initial hypothesis was not proven but the study revealed:
- the expected higher prevalence of diabetes.
- age at onset earlier than in the general population
- an even higher prevalence of other autoimmune disorder (thyroid disorder,
coeliac disease, tooth or nail problems, alopecia and vitiligo) among
this subgroup than in DS as a whole, suggesting that they may carry
a particularly high risk of aggressive autoimmune disorder.
The group is continuing to investigate how trisomy 21 confers increased
autoimmunity and now need more subjects to extend the study.
Julian writes:
'We are studying the increased incidence of type 1 diabetes in children
with Down's syndrome. Diabetes occurs at a frequency ten times above that
of the general population and at an earlier age. We feel that understanding
the aetiology of this increased risk might allow us to understand the
increased frequency of autoimmune diseases in general seen in Down's syndrome
(DS). We have recruited 50 cases of children and adults with type 1 diabetes
and DS and 100-200 controls children with DS alone. So far, we have evidence
that the classical autoimmune haplotypes for type 1 diabetes in the general
population are not such a big factor in Down's syndrome so there must
be loci(genes) on chromosome 21 that are important. We would like to recruit
more children or adults with both type 1 diabetes (age at diagnosis <20
years) and DS to further our studies. We have ethics committee approval
for this study.
We need a little extra blood (1-2 mls clotted, 1-2 mls EDTA) taken when
venous sampling is already being undertaken for clinical reasons such
as thyroid function tests.
If you do have any children or adults with both conditions and are
willing to help please contact me for further details.
Institute of Child Health, St Michael's Hill, Bristol,
BS2 8BJ.
Tel: 0117-9215411 Bleep:
2353/air call, Dr Julian Shield Email:j.p.h.shield@bristol.ac.uk
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