Completing
the jigsaw puzzle: an important piece is in place.
(Aug 2000).
What
causes Hailey-Hailey disease?
The condition
is caused by a change (mutation) in a gene on chromosome 3.
Now researchers in the UK and USA have discovered that this
gene makes a "calcium pump".
What
does the pump do?
This "calcium
pump" is found within the cells of the skin (keratinocytes).
Cells use calcium to produce signals that tell a complicated
"machinery" inside the cell what to do and when to do it.
Cells store calcium in tiny containers inside the cell. We
believe that the pump sits in the wall of a container - called
the Golgi apparatus.
The cell
makes signals by letting calcium out of the containers. Changes
in the amount of calcium as it is released and then pumped
back into the container can be measured. The rapid changes
in calcium are measured as a number of tiny spikes. The pattern
of spikes makes a very complicated signal, but we do not know
exactly what the changes in calcium spikes say. It is rather
like hearing Morse code but not understanding what the dots
and dashes mean. We need "code breakers" so we can unravel
exactly how the calcium messages switch the machinery on and
off.
We know
that calcium-signaling controls the "machinery" that makes
the sticky junctions (desmosomes) that hold skin cells together.
If the "machinery" does not work properly, the sticky junctions
may not be made correctly. In Hailey-Hailey disease, the pumps
in skin cells to do not work properly. We suspect that faulty
signals affect the skin cells so that the sticky junctions
are not made correctly, the cells do not hold together and
the skin forms raw areas or blisters.
How
will this discovery help treatment of Hailey-Hailey disease?
This discovery
is a very important step because once we understand exactly
what is going wrong we will be in a much better position to
put things right. We are still a long way from finding a better
treatment but we are getting closer.
Will
extra calcium help Hailey-Hailey disease?
No. Your
body is not short of calcium. It will make no difference to
the signaling if you eat more calcium or if you rub a cream
containing calcium on your skin.
Next
Steps.
Clinical
scientists would like to understand
- exactly
how the pumps work inside skin cells
- how
signals affect the machinery in the cells
- what
happens to the signaling in Hailey-Hailey disease
- why
infections make Hailey-Hailey disease worse
- how
steroid creams affect the pumps
Thank
you
Clinical
scientists and dermatologists would like to thank all the
families and individuals who have and are continuing to help
with this work. These advances would not have been possible
without your co-operation.
Susan
Burge DM FRCP
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