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Professor Richard Trembath and
I'm going to talk to you today
about the molecular genetics of
pulmonary arterial hypertension.
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Pulmonary hypertension is
defined as an elevation
of the pulmonary arterial pressure
and has a multitude of causes.
The recent classification
from an expert group
identified some of the
associated conditions that
can lead to an elevation
of the pressure
within the pulmonary
arterial circulation.
A noted important group of patients
who have no known or recognized
associated cause and
fit into the category
of heritable and idiopathic
pulmonary arterial hypertension
are the focus of this talk.
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The characteristic histopathology
of pulmonary arterial hypertension
in its idiopathic
and heritable form is
one of increase in
the smooth musculature
of the pulmonary arterial
circulation, a predisposition
to formation of
intravascular thrombosis
and occlusion together with
the pathognomonic plexiform
lesions that are shown in
this illustration in panel D.
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Pulmonary arterial hypertension
can and is frequently
transmitted as a familial disorder.
In this slide we show the
characteristic pattern
of inheritance with a autosomal
dominant mode of transmission--
multiple affected family members
over several generations.
But clearly the gene is acting
with reduced gene penetrance
with individuals transmitting the
disease indicated in the slide
in gray, and yet not
developing the characteristic
clinical or
histopathological features.
Though it also
indicated in the slide
is the variable age of onset--
the numbers below the individuals
indicating the age at which
clinical symptoms became apparent.
And finally, as is true
for both idiopathic disease
and when the disease is present
within multiple family members,
there is a sex bias despite the
autosomal nature of the condition
with females more
frequently affected
than males with the
ratio of 2.5 to one.
