253
GENETIC REGISTERS IF genetic counselling is to achieve its full potential in reducing the birth frequency of genetically determined disease, all men and women at risk of having children
with such disease must know their risk and understand its full implications. In present practice a consultant in a genetic clinic informs a couple of their risks and tries to put this risk into perspective for them, both in relation to the random risk and the prognosis for the future child if affected. But the extent to which all other members of the family who are also potentially at risk of having affected children are ascertained and told of their risk is a matter for the consultant’s conscience and of the resources to which he has access. Further, one or more of the relatives newly recognised to be at risk of transmitting the disease may themselves be infants, who will not have to make decisions on planning a family for another twenty years. Will the family always remember. and the medical records be available? Computerised genetic registers make it much easier to keep records of those at risk and to see that at an appropriate time, through the family doctor, the problem is brought forward again, any necessary tests are made, and information is given to the young man or woman on the special risks and what action might be taken to avoid or lessen the chance of disease. An example is a family of which some young members carry a balanced chromosomal translocation, with a risk of chromosomally unba- . lanced mentally and physically handicapped children-a risk which these youngsters might wish to take in due course only with the safeguard of prenatal screening of each pregnancy. Another example is the young daughter of a woman who is a known carrier of the gene for X-linked severe muscular dystrophy. The daughter, once she knows of her 1 in 2 risk of being a carrier, will wish for tests to estimate the probability that she is in fact a carrier, and also be glad of information on the possibility of prenatal diagnosis of affected male fetuses. A third example is the young children of a man in whom Huntington’s chorea, or the adult form of polycystic disease of the kidneys, has recently been recognised. When these children grow up the chance of their carrying the gene will be close to 1 in 2, and in the case of polycystic disease, but not yet of Huntington’s chorea, there are helpful investigations to determine whether the individual has inherited the gene or not. It is in the dominant diseases of adult onset that genetic counselling, and a register, may have greatest impact. For example, no very satisfactory data exist on the proportion of cases of Huntington’s chorea that are due to fresh mutation; but it may be only about 10%, and some would put the proportion even lower. This implies that each mutant gene persists and affects individuals on average for 10 generations. Even though we have no preclinical tests for those who carry the gene, young adults with a 1 in 2 risk, when told of their risk and that to their children, usually decide to have no children or only one or two. 12 Warning all those at risk would substantially reduce the number of generations each mutant gene on average persists, and the number of individuals affected by each mutant gene.
1 Evans, K., Carter, C. Unpublished. 2 Tyler, A., Harper, P. Unpublished.
Registers, however, raise serious problems of acceptability and confidentiality. Unauthorised access to a genetic register might severely prejudice an individual’s career. Many people distrust registers, and. particularly computerised registers. A working-party of the Clinical Genetics Society has just published a report on genetic registers,3 and they note that: one computerised Regional register is already in operation in the United Kingdom, at Edinburgh; the Indiana Human Genetics Centre has a computerised register; and in Belgium file on all persons referred to any of the medical Belgian genetic centres, though access to individuals is named only available to the referring centre. In addition there are many registers of patients with individual diseases in the United Kingdom-e.g., haemophilia (several centres), polyposis of the colon (St. Mark’s Hospital, London), and phenylketonuria (Institute of Child Health, London). The working-party recognises the problems created by such registers, the danger of breach of confidentiality, and the possible loss of self-esteem of those referred once they learn their risk of contracting and transmitting disease. They note too that such individuals may need additional medical and perhaps social support after genetic counselling, when no effective treatment yet exists. Briefly the recommendations are that: there is
a master
seven
Registers should be set up for the express purpose of tracand counselling individuals at high risk of transmitting a serious genetic disorder. 2. Such registers are best maintained on a Regional rather than a national basis and in general kept at the Regional genetics centre, with a link to any registers already kept by units concerned with special disorders such as haemophilia. 3. Entries to the register should be made only with the full knowledge and approval of the individual concerned. 4. Regional centres should standardise their methods of recording data. 5. Strict safeguards for confidentiality must be incorporated, with personal medical information accessibility only to the consultant in charge of the register. 6. A dedicated mini-computer in the Regional medical genetics centre provides the most convenient method of ensuring ease of operation and confidentiality. 7. A start be made with the registration of particular genetic disorders of particular importance. 1.
ing
The working-party’s case is strong and the precautions suggested are sensible. But is the public ready for wide deployment of genetic registers? This is something which medical geneticists, community physicians and family doctors might well debate further. Meanwhile pilot regional studies, such as that in Edinburgh, should be encouraged, and we should continue to seek other and less controversial methods of transmitting information on genetic risks to all those who need it.
DIURETIC RESISTANCE? MODERN diuretics have revolutionised the treatment of oedema. Removal of fluid from the pleural and peritoneal cavities by aspiration, or from the limbs by the insertion of tubes, is now rarely practised. Efficient drugs 3.
Emery, A. E. H., et al. J. med. Genet. 1978, 15, 435.
GENETIC REGISTERS IF genetic counselling is to achieve its full potential in reducing the birth frequency of genetically determined disease, all men and women at risk of having children
with such disease must know their risk and understand its full implications. In present practice a consultant in a genetic clinic informs a couple of their risks and tries to put this risk into perspective for them, both in relation to the random risk and the prognosis for the future child if affected. But the extent to which all other members of the family who are also potentially at risk of having affected children are ascertained and told of their risk is a matter for the consultant’s conscience and of the resources to which he has access. Further, one or more of the relatives newly recognised to be at risk of transmitting the disease may themselves be infants, who will not have to make decisions on planning a family for another twenty years. Will the family always remember. and the medical records be available? Computerised genetic registers make it much easier to keep records of those at risk and to see that at an appropriate time, through the family doctor, the problem is brought forward again, any necessary tests are made, and information is given to the young man or woman on the special risks and what action might be taken to avoid or lessen the chance of disease. An example is a family of which some young members carry a balanced chromosomal translocation, with a risk of chromosomally unba- . lanced mentally and physically handicapped children-a risk which these youngsters might wish to take in due course only with the safeguard of prenatal screening of each pregnancy. Another example is the young daughter of a woman who is a known carrier of the gene for X-linked severe muscular dystrophy. The daughter, once she knows of her 1 in 2 risk of being a carrier, will wish for tests to estimate the probability that she is in fact a carrier, and also be glad of information on the possibility of prenatal diagnosis of affected male fetuses. A third example is the young children of a man in whom Huntington’s chorea, or the adult form of polycystic disease of the kidneys, has recently been recognised. When these children grow up the chance of their carrying the gene will be close to 1 in 2, and in the case of polycystic disease, but not yet of Huntington’s chorea, there are helpful investigations to determine whether the individual has inherited the gene or not. It is in the dominant diseases of adult onset that genetic counselling, and a register, may have greatest impact. For example, no very satisfactory data exist on the proportion of cases of Huntington’s chorea that are due to fresh mutation; but it may be only about 10%, and some would put the proportion even lower. This implies that each mutant gene persists and affects individuals on average for 10 generations. Even though we have no preclinical tests for those who carry the gene, young adults with a 1 in 2 risk, when told of their risk and that to their children, usually decide to have no children or only one or two. 12 Warning all those at risk would substantially reduce the number of generations each mutant gene on average persists, and the number of individuals affected by each mutant gene.
1 Evans, K., Carter, C. Unpublished. 2 Tyler, A., Harper, P. Unpublished.
Registers, however, raise serious problems of acceptability and confidentiality. Unauthorised access to a genetic register might severely prejudice an individual’s career. Many people distrust registers, and. particularly computerised registers. A working-party of the Clinical Genetics Society has just published a report on genetic registers,3 and they note that: one computerised Regional register is already in operation in the United Kingdom, at Edinburgh; the Indiana Human Genetics Centre has a computerised register; and in Belgium file on all persons referred to any of the medical Belgian genetic centres, though access to individuals is named only available to the referring centre. In addition there are many registers of patients with individual diseases in the United Kingdom-e.g., haemophilia (several centres), polyposis of the colon (St. Mark’s Hospital, London), and phenylketonuria (Institute of Child Health, London). The working-party recognises the problems created by such registers, the danger of breach of confidentiality, and the possible loss of self-esteem of those referred once they learn their risk of contracting and transmitting disease. They note too that such individuals may need additional medical and perhaps social support after genetic counselling, when no effective treatment yet exists. Briefly the recommendations are that: there is
a master
seven
Registers should be set up for the express purpose of tracand counselling individuals at high risk of transmitting a serious genetic disorder. 2. Such registers are best maintained on a Regional rather than a national basis and in general kept at the Regional genetics centre, with a link to any registers already kept by units concerned with special disorders such as haemophilia. 3. Entries to the register should be made only with the full knowledge and approval of the individual concerned. 4. Regional centres should standardise their methods of recording data. 5. Strict safeguards for confidentiality must be incorporated, with personal medical information accessibility only to the consultant in charge of the register. 6. A dedicated mini-computer in the Regional medical genetics centre provides the most convenient method of ensuring ease of operation and confidentiality. 7. A start be made with the registration of particular genetic disorders of particular importance. 1.
ing
The working-party’s case is strong and the precautions suggested are sensible. But is the public ready for wide deployment of genetic registers? This is something which medical geneticists, community physicians and family doctors might well debate further. Meanwhile pilot regional studies, such as that in Edinburgh, should be encouraged, and we should continue to seek other and less controversial methods of transmitting information on genetic risks to all those who need it.
DIURETIC RESISTANCE? MODERN diuretics have revolutionised the treatment of oedema. Removal of fluid from the pleural and peritoneal cavities by aspiration, or from the limbs by the insertion of tubes, is now rarely practised. Efficient drugs 3.
Emery, A. E. H., et al. J. med. Genet. 1978, 15, 435.
