Cytogenetics Website
- Introduction to the Laboratory
The Cytogenetics unit was established as a diagnostic service at St James's Hospital in 1967 to provide a chromosome analysis service for the Yorkshire region. We are a CPA accredited laboratory
The Cytogenetics laboratory at Leeds is part of the Yorkshire Regional Genetics Service. This service provides genetic counselling to individuals and/or families identified as being at high risk of developing or passing on a genetic disorder and offers information and support in order to allow people the widest possible choice when making decisions related to their genetic risk. Referrals are through health care and related professionals both within the hospital and the community.
- User Guide for the Laboratory
The work of the department can be broken down into six main areas. Click on the links below for more information.
Blood samples - this category comprises the major part of the workload. Urgent samples include those from newborn babies and pregnant women and their partners. Non-urgent referrals include patients with a history of pregnancy loss, children with learning difficulties or physical disabilities, and individuals with impaired physical or sexual development.
Prenatal Diagnosis - Prenatal diagnosis is carried out by one of three methods - chorionic villus biopsy, amniocentesis or fetal blood sampling. Indications for prenatal diagnosis include advanced maternal age, problems detected on ultrasound scan, risks identified through measuring biochemical markers, and the presence of a family history of a chromosome abnormality. The main abnormality detected is Down Syndrome.
Solid Tissues - Since up to 50% of all spontaneous abortions may have a chromosome abnormality, products of conception after a pregancy loss may be referred for chromosome analysis. Skin biopsies from living persons are also occasionally received either for cytogenetic analysis or for referral onwards for biochemical testing or DNA studies.
Haematological disorders - Patients with a suspected leukaemia or other haematological disorder may be tested for the presence of an acquired chromosome abnormality. Cytogenetics can provide diagnostic and prognostic information on the disease status. The tissue of choice is usually bone marrow, though blood and other involved tissues are occasionally examined.
Solid Tumours - Tumour samples from the majority of childhood cancers are investigated in a similar way to bone marrows in order to detect acquired chromosome abnormalities. Some selected adult cancers are also investigated.
Molecular Cytogenetics - This area of work is concerned with the investigation of chromosome abnormalities at the molecular level. Chromosome specific probes and paints are used to determine chromosome changes which cannot be identified by light microscopy. This can increase the detection rate and provide a clearer picture of chromosome abnormalities.
Regions we cover
Hospital we receive frequent referrals from:
Northallerton, Scarborough, Hull, Scunthorpe, Grimsby, Pontefract, Wakefield, Calderdale, Airedale, Harrogate, York, Leeds General Infirmary, St James's Hospital, Bradford, Dewsbury. Although we are happy to receive referrals from any hospital.
- Introduction to Cytogenetics
Cytogenetics is the study of chromosomes and chromosomal abnormalities. The normal number of chromosomes in a human cell is 46. Chromosomes are made from DNA, and contain all the genes present in a cell. Each gene is located at a specific site on each chromosome. There are many clinical syndromes that have been associated with particular chromosomal abnormalities. Figure 1 shows a normal male chromosome complement.
Figure 1.
Chromosomal abnormalities usually involve large amounts of DNA and therefore tend to involve large numbers of genes. For this reason, disorders associated with chromosomal abnormalities are usually very serious and can involve multiple organs. Often these abnormalities are severe enough to be fatal, either in utero or in early life.
Each normal human cell contains 23 pairs of chromosomes. 22 of these pairs are identical, the other constitutes the sex chromosomes (one X and one Y in a male and two X's in a female).
The largest chromosome in the human complement is numbered '1' and the smallest '22'. Modern techniques within the laboratory allow the chromosomes to be identified from one another by distinguishing bands on the chromosomes.
Last Updated: 26.02.10
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