FM OCTOBER 2018 ISSUE - digital edition

in Lucknow, All India Institute of Medical
Sciences in Delhi, Postgraduate Institute
in Chandigarh, Manipal University in
Mangalore). The total medical geneticists
in the country may be about 100, which
is totally inadequate for a country the
size of India.
Similarly, these tests only measure the probability
for a limited number of conditions, while amniocentesis
and CVS can be used to test for a much broader number
of genetic abnormalities, emphasises Nateram, which
makes SNP-based Panorama NIPT.
Clearly, the technical ability to test for a condition
does not necessarily correspond with a clinical benefit.
Hence it is important for the companies to be certain
about the benefit of every new addition.
“Test results must aid clinical decision-making and
should be beneficial to patients. Each condition added to
a screening panel adds to the overall false positive rate
of the test and decreases the positive predictive value,’’
says Dr Schmid of Roche Sequencing Solutions, which
recently included 22q11.2 microdeletion testing as part
of its prenatal test portfolio. Therefore, additional cfDNA
test menu options must focus on clinically relevant
conditions and require comprehensive validation studies
to demonstrate clinical utility in the population to be
tested.
Furthermore, counselling becomes more challenging
with an increase in the complexity of testing options and
the potential of identifying conditions with an uncertain
prognosis, according to Dr Schmid.
Test results
must aid clinical
decision-making
and should be
beneficial to
patients. Each
condition added
to a screening
panel adds to
the overall false
positive rate
of the test and
decreases the
positive predictive
value.
Maximilian
Schmid M.D.
Head of Medical
Affairs, Roche
Sequencing Solutions,
California
HEARING LOSS
MEDGONOME OFFERS
GENETIC TESTING
FOR COUPLES
MedGenome Labs, a genomicsbased
research and diagnostics
company, offers genetic testing
for couples with a family history of
hearing loss.
Awareness and early detection
are the only ways to prevent
genetic hearing loss disorders
from being passed down to next
generations.
Couples should undergo
pre-conception counselling with a
genetic counsellor, especially when
there is positive family history
for a disorder. Such counselling
sessions help the couple better
understand the risk to the child as
well as help recommend a suitable
prenatal genetic test, according
to Dr Sunitha Tella, head, Clinical
Genetics and Fetal Medicine
Department, Institute of Genetics
and Hospital for Genetic Diseases,
Hyderabad.
“In one such case, the
first born child had cognitive
disorders. It was recommended,
to understand if the hearing
impairment was due to genetic
factors basis, which appropriate
screening measures could be
taken when they plan a second
child,” she said. Dr Tella suggested
the family to undergo genetic
testing at MedGenome Labs,
Bengaluru.
The blood samples of the
parents and their first child
revealed their first born had two
mutations or variants in the GJB2
gene, which is associated with
hearing loss, while the parents
were found to be carrying one
mutation each, making them
‘carriers’ of the disease. This meant
that their child may have 25 per
cent chance of being affected with
hearing impairment.
The foetus was tested
for these two variants and
was found that it was only
harbouring one of the two
mutations found in the first
child. In this case the child
would be a carrier of the
disease and wouldn’t suffer
from hearing loss, she added.
2018 / FUTURE MEDICINE / 25