PKD Life - Summer 2022 - 11

DOCTOR Q&A
The Screening Dilemma
Insights and advice from pediatric nephrologist
Christian Hanna, M.D.
With Debra Gordon
Q What do parents say?
If parents say they don't
A utosomal dominant polycystic kidney disease
(ADPKD) is, as the name implies, a genetic disease.
You need only one copy of the mutated gene to have it,
which means that each child of a parent with ADPKD
has a 50% chance of inheriting the disease. Yet the
condition often remains undiagnosed until middle age.
This begs the question: Should the children of a parent
with ADPKD be screened for the disease? We talked to
Christian Hanna, M.D., a pediatric nephrologist at the
Mayo Clinic in Rochester, Minnesota, about this topic.
Q How does ADPKD
manifest in children?
In pediatrics, it's uncommon to
be born with severe ADPKD or
develop the disease symptoms
in early childhood. Most children
we see were incidentally
diagnosed when they underwent
abdominal imaging
studies unrelated to ADPKD or
were having nonspecific symptoms
associated with ADPKD,
such as nighttime urination,
urinary tract infection, or back
pain. The worst symptom is
if we see high blood pressure
and protein in the urine, which
are early signs of kidney damage
and polycystic kidney
disease. Some of our patients,
however, were screened for
ADPKD when a family member
was diagnosed.
family is diagnosed
with ADPKD and has young
children, do you think their
kids should be screened?
Q If an adult in the
Among the pediatric
nephrology community, there
is a debate about whether to
screen children. We counsel
parents about the benefits
and risks of finding the diagnosis
and let them make a
decision with their children.
Number one, we need to
respect the autonomy of the
child. I think older children
should be involved in the
decision-making and understand
what this means for
them and their future.
There is no FDA-approved
treatment for children to slow
the disease progression, and
there's no data yet to suggest
that screening these children
before they have symptoms
improves their outcomes. But
there are some preventive
actions that can be initiated
before adulthood, such as high
fluid intake, healthy diets, and
salt restriction, as well as a
healthy lifestyle, exercise, and
maintaining a healthy weight.
want to screen their children,
we recommend annual
monitoring to check for any
high blood pressure or protein
in the urine. If the child
starts having hypertension
for an unknown cause and
has a strong family history
of ADPKD, it makes sense to
screen these children with a
kidney ultrasound for cysts
and treat their high blood
pressure, which is a risk factor
for ADPKD progression.
Q Where are we on getting
pediatric approval
for tolvaptan, the only
approved drug for ADPKD?
The first trial in children
was a phase 3 clinical trial in
Europe evaluating the safety,
tolerability, and efficacy of
tolvaptan in those ages 4-17.
Participants were randomly
assigned to either tolvaptan
or a placebo. The study is
over, but the results haven't
been reported yet.
One potential challenge
with tolvaptan trials in children
is that they must drink a
lot of water because the drug
makes them urinate a lot.
And many children simply
don't want to do that.
Q What other PKD
research is going on
in the pediatric population?
There is an unmet need
to better characterize
biomarkers in pediatric
populations that predict
ADPKD progression in later
life. This can help us identify
therapeutic targets and
stratify patients for preemptive
treatment. Our Translational
Polycystic Kidney
Disease Center at the Mayo
Clinic is collecting blood
and other tissue samples, as
well as imaging studies, to
look for biomarkers associated
with diagnosis and the
rate of disease progression.
This would provide data for
clinical trials of medications
to see if they can slow
the disease progression.
Centers in the U.S. and
Europe are also collaborating
by building pediatric
ADPKD registries.
The question is if we can
develop a medication that
is safe for children and that
could push the end-stage
kidney disease or kidney
failure from age 55, which
is the average age of kidney
failure onset in most
patients, out to 70 or 80. It
will take years to get to this,
however.
Q Anything else
you'd like to say?
We need to change the
thinking that ADPKD is only
considered an adult disease.
It's an autosomal dominant
polycystic kidney disease,
and kids are affected if they
carry the gene mutation.
*
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PKD Life - Summer 2022

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