Information On The Methods and Results For Chromosome Analysis

Submitted on March 27, 2012

What is Chromosome Analysis?

A chromosome analysis is a method that is used to identify chromosomal abnormalities. This procedure is also called karyotyping. The test involves analyzing the chromosomes contained in a cell sample to identify genetic disorders or diseases. It is also used to analyze the structure of the chromosome.

Chromosome abnormalities can be a cause of birth defects like Down's syndrome and Turner's syndrome and can also be responsible for infertility and miscarriages. Depending on the need, a chromosome analysis can be done using the following methods

Methods Used For Performing Chromosome Analysis

  • Blood analysis - A sample of the blood is collected from the vein.
  • Bone marrow analysis - A sample of the bone marrow is collected using a biopsy procedure.
  • Biopsy of the placenta in pregnant women.
  • Amniocentesis - Analysis of the amniotic fluid in pregnant women.

The analysis normally does not require any preparation, and the results are available in a few days.

After the samples are collected, they are first grown in the laboratory and then stained. The lab technician then uses a microscope to analyze the chromosomes. The results of a chromosome analysis can either be normal or abnormal.

Under normal circumstances, 46 chromosomes need to be found, 44 of which are called autosomes and the remaining 2 are sex chromosomes. Sex chromosomes can help to identify the sex of the baby. A chromosome count that is lesser than or greater than 46 indicates a chromosome abnormality and can be an indication of the following conditions:


  • Down's syndrome - This causes a delay in mental and physical development of a child. This is caused due to an extra chromosome.
  • Kilnefelter's syndrome - Can cause infertility and development of testicles that are small in size. This syndrome normally affects men and is caused when there is an additional X sex chromosome.
  • Philadelphia chromosome - Can lead to leukemia. This condition is caused due an interchange of genetic materials across two chromosomes.
  • Turner's syndrome - Can lead to lack of growth in girls and can also prevent the ovaries from developing properly. This syndrome normally occurs when one of the two sex chromosomes are missing.

It is important to know that cancer treatments such as chemotherapy can have an impact on the chromosome count.

Chromosome analysis is also used in the area of forensic sciences. A technique called STR or short tandem repeat is used in finger print analysis. The results of an STR chromosome analysis are used to create a DNA database for further analysis.

Chromosome analysis is a very powerful tool that can help to proactively identify medical problems when the child is in the womb. This can help a doctor to identify an appropriate treatment well in advance.