00:01
This is G6PD deficiency.
00:03
This is the first enzyme deficiency
that we’re going to take a look
at under normocytic anemia
and we are dealing with, well, hemolytic
where you have increased reticulocytosis.
00:15
What is G6PD?
It is glucose phosphate
dehydrogenase.
00:20
Where do you find this enzyme?
Well, you find this, well, think
about the glycolytic pathway
and I want you to branch
off the glycolytic pathway
and go into what’s known as a hexose
monophosphate shunt or HMP shunt.
00:34
This particular shunt, HMP shunt,
is responsible for producing your?
NADPH.
00:41
So you take the P in the
pentose phosphate pathway
and apply it to what kind
of NAD—not NADH, but NADPH.
00:52
And why do we in normal physiology
require NADPH or biochemistry?
It’s the fact that we need
NADPH so that we can produce
proper amounts of
glutathione, right?
Glutathione.
01:04
And what does glutathione do for us?
It then allows for us to then properly
manage and protect ourselves.
01:10
Why is this so
important for the RBC?
Well, the RBCs require proper
months of NADPH and glutathione
so it can protect itself
against antioxidants, right?
Antioxidants.
01:22
Think about a normal mature RBC,
central pallor, it is naked.
01:27
It has no nucleus.
01:28
It has no mitochondria.
01:30
The only method by which it can truly
protect itself is through this HMP shunt.
01:34
So it is big deal.
01:36
Now, something that I wish
to bring to your attention
about this very important rate-limiting
enzyme of your HMP shunt
is the fact that the half-life of
a normal enzyme here is 62 days.
01:48
So that’s over two months.
01:50
So what then happens when
you have G6PD deficiency?
And we’ll talk about this as being
an X-linked recessive disease
and so therefore a male,
such as myself,
well, I have no choice, meaning to say that
if I was to then inherit the X chromosome,
and that’s where the mutation is,
then I obviously will
have G6PD deficiency.
02:13
What about a female?
With a female, maybe one X is the mutated
one while the other X is perfectly normal.
02:20
So therefore, she would
have a trait, are we clear?
Now, if there is such a mutation
taking place with X-linked recessive,
then what then happens
to the enzyme?
Take a look at the half-life here.
02:30
The normal 62 drops all
the way down to 13.
02:34
That’s not a lot of time for an
enzyme to remain active in one's body.