Glimpses 2009-2010.pdf - LV Prasad Eye Institute

Genetic testing for retinoblastoma:
Retinoblastoma is a cancer of the eye that affects infants and
young children, usually below the age of 5 years. It can be
treated more effectively and the child’s eye as well as his/her
life can be saved if detected in the early stages. The formation
of retinoblastoma is triggered by an alteration of a gene known
by the same name (RB1 in short), and a parent who has such an
altered (mutated) copy of the RB1 gene can pass on the gene
to the children who are consequently at risk of developing the
tumor. Our research team, including Vidya Parsam from the
Kallam Anji Reddy Molecular Genetics Laboratory, Dr Santosh
Honavar and Dr Md Javed Ali from the Ocular Oncology
Service, and Dr Geeta K Vemuganti from the Ophthalmic
Pathology Service are looking at ways of identifying mutations
in the RB1 gene among patients with retinoblastoma. This would reveal the underlying cause for the
disease, so that if a mutation is found in a patient, his or her relatives can be screened to see who is
at risk of developing the tumor.
Using a combination of techniques in the molecular genetics laboratory, we developed an effective
procedure for detecting RB1 mutations and have been able to successfully identify the underlying
mutations in over 80% of patients we tested. The tests were also designed in a way that would reduce
the costs of chemicals involved. Apart from designing an effective screening test for predicting those
at risk for developing retinoblastoma, we also have interesting observations on the kinds of genetic
alterations in RB1 that are responsible for this form of cancer. By using different approaches, we have
found novel and unexpected alterations in the gene. Vidya Parsam, the research fellow on this team,
got recognition for this work — a Young Scientist award from the K V Rao Scientific Society and a
travel fellowship to attend the annual meeting of the ARVO in May 2010, to present a paper. This test
can be set up for routinely screening families who desire to be tested. If a child is at risk by virtue of
having the defective gene, he/she needs to undergo frequent examination to detect the tumor early,
while those who do not carry it need not be subjected to frequent examinations.
Chitra Kannabiran
Kallam Anji Reddy Molecular Genetics Laboratory
A low cost method for field based diagnostics – the LAMP assay
Molecular diagnostics, especially
Polymerase Chain Reaction (PCR) is widely
used for the rapid diagnosis of infectious
diseases. PCR uses precision equipment
including a thermal cycler, electrophoretic
apparatus and a gel documentation system
to detect the presence of pathogen DNA.
The expense and expertise associated with
such equipment is a major obstacle to its
widespread use in secondary and primary
health care settings. Recently, scientists
at the Prof Brien Holden Eye Research
Centre developed a cost effective Loop
mediated isothermal Amplification assay
(LAMP assay) for the rapid detection of
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