GENETICS LABORATORY
Our state-of-the-art laboratory offers Cytogenetic tests such as Karyotyping and FISH (fluorescence in situ hybridization) as well as Molecular Genetic tests like PCR (Polymerase Chain Reaction) for Y chromosome microdeletions.
Cytogenetic tests are carried out on suspicion of a chromosome anomaly in newborns, children, adults, the unborn child in high-risk pregnancies or an aborted fetus (products of conception). They are also carried out in patients with blood cancer or leukemia, and help in their diagnosis and management. Tissue culture is done in a majority of cytogenetic tests, hence strict aseptic precautions are necessary for sample collection. Karyotyping involves the analysis of all 23 pairs of chromosomes. The FISH test is used when certain specific chromosome abnormalities are suspected.
Karyotyping
Karyotyping is a detailed analysis of chromosomes to detect abnormalities of the number or structure of chromosomes. The chromosomes are obtained from peripheral blood samples after culture for 72 hours. The metaphases are fixed on slides, Geimsa banded, mapped and analyzed for abnormalities. We have the Zeiss/Metasystems automated karyotyping workstation where images of the metaphases are captured, processed and stored. Numerical and structural chromosome abnormalities like trisomies, deletions and translocations can be detected.
FISH
Fluorescence in situ hybridization (FISH) is a new and rapid procedure to detect certain common chromosome abnormalities. We use directly labeled commercially available Vysis (Abott) FISH probes which are complementary to the region of interest on a particular chromosome. The analysis is usually done by counting colored dots under a fluorescent microscope. The cells are pretreated and fixed on slides. The slides are dehydrated, co-denatured with appropriate probe, hybridized, washed and mounted in antifade solution together with counterstain. The FISH signals are observed under a Zeiss fluorescence microscope using appropriate filters and the images are captured and analyzed with the Metasystems software. FISH is a rapid technique to detect common aneuploidies and low-grade mosaicism mainly in prenatal diagnosis, products of conception and pediatric cases. Common translocations in leukemia can also be analysed semi-quantitatively, to determine response to therapy and detect minimal residual disease. Analysis by FISH is possible even on interphase nuclei.
PCR
PCR is an in vitro DNA amplification procedure that can, in a matter of hours, isolate and amplify a specific segment of DNA by as much as a billion fold. This involves several steps that allow a specific DNA sequence to be replicated several times and then rapidly analyzed by electrophoresis. We detect mutaitons like Y chromosome microdeletions by multiplex PCR in certain cases of infertility.
List of Genetic Diagnostic tests carried out in our Department :
- Karyotyping from Blood (routine)
- Karyotyping for chromosomal variations from blood
- Chromosomal breakage study :
- Karyotyping from Bone marrow (in leukemias)
- Karyotyping from Products of conception (in aborted fetuses)
- Karyotyping for Prenatal Diagnosis (from CVS, amniotic fluid, cord blood)
- FISH for Aneuploidy (13, 21 and/or 18, X, Y and/or 16, 22)
- FISH for infertility: (18, X, Y) / (13, 21)
- FISH for microdeletion syndromes
- FISH for hematological malignancies
- FISH from urine cells for bladder cancer recurrence
- PGD by FISH (13, 18, 21, X and Y)
- PCR for Y chromosome microdeletions (20 mutations)
- Sperm Apoptosis by TUNEL method
Fanconi Anemia
Ataxia telangiectasia
Bloom Syndrome
Sister Chromatid Exchnage study
Fragile X Syndrome
Sperm
Follicular fluid
Urine
Buccal cells
Prader Willi syndrome
Angelman syndrome
Williams syndrome
DiGeorge Syndrome
Duplication 15 (Autism)
BCR/ABL t(9;22)
PML/RARA t(15;17)
AML1/ETO t(8;21)
inv(16)
Burkitts Lymphoma (8q24)
RARA (17q12-q21) rearrangement
del(13q14)
CLL panel to check for deletions of 11q23, p53, 13q14.3, 13q34 and Trisomy 12
Deletion 13q14.3 and 13q34 in Myltiple Myeloma
