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0:00
Hello.
My name is Eric Legius.
I'm a human genetics professor
at University of Leuven,
and I want to introduce you
in the interesting world
of neurofibromatosis type
one and the rasopathies.
0:16
Neurofibromatosis step
one is a genetic disorder
with an autosomal dominant
inheritance pattern.
Its gene is known, and it's
localized on chromosome 17,
band q11.2.
The prevalence at
birth is one 2,700.
It is considered to be a
familial tumour syndrome.
On the other hand,
cognitive problems
such as learning
disabilities are also
very frequently
observed in children.
The diagnosis is based
on clinical criteria.
0:51
In 1988, an NIH panel has
made diagnostic criteria
for the clinical diagnosis of
neurofibromatosis type one.
On this slide, all the
different criteria are listed,
and two or more of
these criteria have
to be fulfilled to make
a clinical diagnosis
of neurofibromatosis type one.
And on the next slide, we will show
several of these clinical features.
1:20
On this slide, we see
seven different images.
They all represent
different criteria
for the clinical diagnosis of
neurofibromatosis type one.
The left upper image shows you the
multiple cafe-au-lait spots that
can be seen on the
skin of individuals
with neurofibromatosis type one.
They're usually present
in the first year of life.
The upper middle image
shows us axillary freckling.
Axillary freckling represents
small pigmented dots in the axilla.
The same type of freckling can
also seen in the inguinal region.
The right upper image shows
cutaneous neurofibromas.
We see the left upper
arm of an individual
with neurofibromatosis
type one, and we
see three different
cutaneous neurofibromas.
Some of these
cutaneous neurofibromas
have overlying skin which
is slightly violet in color.
And this is typically seen in
these cutaneous neurofibromas.
When we go to the lower panel
of this slide, on the left side
we see the right upper arm
of an individual with NF1
with a very large
hyper pigment region.
And this region also
shows hypertrichosis
Under this region
with hyperpigmentation
and hypertrichosis, there is
a plexiform neurofibroma which
is a larger tumor consisting of
several nerves and nerve branches.
If you palpate this region,
you will feel a mixture
of soft and hard
tissues and nodules.
And some of these nodules
might be painful to the touch.
In the middle part of this slide,
we see the iris of the eye.
And in the iris of the eye, we see
small pigmented regions in globs.
And these are globs or
nodules of melanocyte.
These nodules are called Lisch
nodules and are very specific
and typically seen in
neurofibromatosis type one.
Under the iris, we see the
CT scan of the brain, which
is focused on the eyes
and the optic nerves.
And one of the optic
nerves is greatly enlarged
and shows an optic pathway glioma.
On the right lower
side, we see the lower
limb of an individual with NF1.
And we see that the tibia is bent.
And at the position
where the tibia is bent,
we see a small cyst and a fracture.
This represents
tibial pseudarthrosis.
