DNA

DNA or Deoxyribonucleic acid is the substance in which genetic information is found. It is found in the cell nucleus of all body cells. The chromosomes found in the cell nucleus contain the DNA and thus the genetic information.

Banking DNA

DNA is often banked (stored) from individuals who have been affected by cancer in a moderate risk family. The clinician dealing with the family will decide if DNA storage is indicated. It is up to the individual to decide if they are willing to supply a sample. The blood sample will only be taken after written permission for DNA storage has been obtained.

Reasons for banking DNA

Currently there may not be the technology easily available to genetically analyse the sample from a moderate risk family, but this may be an option in the future. Thus, if DNA is banked, there may be possibility one day of examining the genes of unaffected individuals in a family, using the DNA information even if the affected member is no longer alive.

Obtaining a DNA sample from a patient

DNA can be obtained from a variety of body cells such as tumour blocks, skin or blood samples. Usually DNA is obtained from a venous blood sample, which is obtained in the usual manner. DNA is extracted in the laboratory from the white cells contained in the sample.

When to take the blood sample

The sample can be taken at any time, it is not affected by chemotherapy. Thus, the sample may be obtained when the patient is having other routine bloods taken at a hospital out-patient appointment for example.

Written consent is needed to bank a DNA sample

Written consent for DNA banking is always needed. Copies of the consent form are available from this website. The DNA sample will not be analysed without further written permission from the patient or if they have died, their relatives.

Practicalities - blood tubes, forms and where to send the sample

The blood sample should be taken using an EDTA (red topped) tube. Two tubes of blood are usually taken, especially from individuals who might have a low white cell count following chemotherapy etc. The blood samples must be accompanied by a Molecular Genetics (green) blood form and sent to the regional genetics laboratory:

West Midlands Regional Genetics Laboratory
Birmingham Women's Hospital
Edgbaston
Birmingham
B15 2TG

It is essential that details of the patient's date of birth, postcode and GP are recorded on the form along with the other usual details. Supplies of EDTA tubes and equipment are available from your local supplier or the Clinical Genetics Unit at Birmingham Women's Hospital.

Storage of the sample

DNA is extracted from the sample by staff in the molecular genetics laboratories at the West Midlands Regional Genetics Service. DNA samples are stored in a freezer until required for analysis.

Consent to analyse the blood sample

The sample will not be analysed without further written permission from the patient, or if they have died, their relatives.