THE IMPLICATIONS OF GENETIC TESTING FOR EMPLOYMENT

ANNEX C

GLOSSARY

Autosomal dominant disorder: disorders where inheritance of a mutation from one parent only (or arising anew during egg or sperm formation) can be sufficient for the person to be affected. Common dominant disorders in the UK include familial hypercholesterolaemia, Huntington's disease, adult polycystic kidney disease and neurofibromatosis (see below for recessively inherited disorders).

Genetic disorder: a condition which is the result of alterations in the genetic make-up of an individual. They may be the direct consequences of defects in single genes (mutations); or in whole chromosomes, parts of which may be lost, duplicated or misplaced; or from the interaction of multiple genes and external factors.

Genotype: the genetic make-up of an individual.

Human Genome Project: an international scientific collaboration to clone, map and sequence the entire human genome (i.e. 3 billion base pairs; approximately 100,000 genes). It is expected that the complete sequence will be known by about 2003 or possibly sooner.

Late onset condition: disorders that normally become symptomatic in adult life although the abnormal gene is present from conception (e.g. Huntington's disease with onset, typically, in early 40s).

Occupational health: the study of health problems -associated with the working environment.

Phenotype: the appearance (physical, biochemical and physiological ) of an individual which results from the interaction of the environment and the genotype.

Recessively inherited disorder: disorders where, for a person to be affected, a mutation has to be inherited from both parents. Such parents are usually unaffected carriers because they only have a single copy of the mutant gene. Common recessive disorders in the UK are cystic fibrosis, haemochromatosis, sickle cell disease and thalassaemia.

Sickle Cell Disease: an inherited abnormality of the haemoglobin which causes distortion of the red blood cells (sickling) under low oxygenation conditions. It mostly affects people of African, African/Asian Caribbean, Eastern Mediterranean, Asian and Middle Eastern origin. Individuals who inherit the gene from each parent have sickle cell disease associated with anaemia and sickle cell crises.

Sickle Cell Trait: Inheritance of one sickle cell gene (sickle cell trait or carrier status) generally is not associated with any significant medical risks under ordinary conditions.