Karyotyping by G Banding Test
Karyotyping by G Banding Test
Karyotyping by G banding is a routine genetic assay that uses Giemsa staining to generate chromosome-specific patterns called G banding. This identifies individual chromosomes and accurately characterises numerical abnormalities and structural rearrangements such as large unbalanced translocations, duplications, deletions, insertions, and inversions.
Chromosomes are structures carrying genes that are passed down from generation to generation. Humans normally have 46 chromosomes arranged in 23 pairs. Each pair consists of one chromosome inherited from the mother and another from the father. Despite the high regulation of the cell division process, sometimes offspring inherit numerically or structurally abnormal chromosomes, resulting in genetic disorders such as Down syndrome or complications during pregnancy like miscarriages.
Karyotyping by G banding, therefore, can be used to find chromosome abnormalities and help diagnose genetic diseases, birth defects, and other immune system disorders.
What is the Karyotyping by G Banding Test Used For?
A doctor might request a karyotyping by G banding
To investigate chromosomal abnormalities in foetus
To identify the genetic causes of recurrent pregnancy losses or infertility in women
To confirm postnatal chromosome aneuploidy (abnormality in number) FISH (fluorescent in situ hybridization) results
To diagnose genetic disorders in adults having family history of aneuploid conditions (such as Down’s Syndrome)
To diagnose and treat blood cancer, multiple myloma, and anemia
Preparation for Test
No specific preparation is required for undergoing G-banded karyotyping testing, but follow your doctor's instructions to ensure smooth sample collection.
Interpretation of Test Results
The report, which helps you to comprehend the karyotype G banding results, is as follows:
Positive (abnormal) results
This report describes the uncommon variations in the number or structure of chromosomes. However, this result could mean any health problem depending on the affected chromosome.
Negative (Normal) results
This report suggests the sample contains the normal number of chromosomes (46) without unexpected alterations.
FAQs
Who should be tested for karyotyping by G banding?
The karyotyping G banding is usually suggested for:
- Couples who have a family history of chromosome abnormalities
- Couples with infertility disorder
- Pregnant woman who's at risk of having a kid with a congenital anomaly
- Women with abnormal prenatal screening test
- Patients diagnosed with cancer or blood disorder
- Infants and children suspected of genetic disorder
Are there any limitations of the Karyotype G banding Test?
One of the primary limitations of karyotyping is the resolution, which is limited to approximately 5-10 megabases of chromosomes, meaning it cannot detect abnormalities smaller than this limit. Also, G-banding is readable only in a specific cell-cycle phase and requires intact chromosomes with good morphology.
What are some types of chromosomal disorders detected by Karyotype by G banding test?
A few examples of chromosomal disorders detected by G banding Karyotyping include:
· Down's Syndrome
· Trisomy 18
· Turner's Syndrome
· Klinefelter syndrome
· Fragile X syndrome
· Double Y syndrome
How long does it take to get the results?
The report may typically take 2-3 weeks, depending on the abnormalities detected in the karyotype.
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