Genetic counselling: evolution or involution?

The need for genetic counselling derives from the peculiarities of genetic information, as compared to other biomedical tests, with particular reference to (a) its predictive character; (b) the existing gap between the ability to diagnose and to treat an inherited disorder, and (c) the psychological, social and ethical problems that genetic testing can raise. Counselling is traditionally performed by healthcare professionals, specifically trained to help individuals to develop ways of dealing with genetic information and gain a better understanding of the problems related with it. The growing number of genetic tests (for rare Mendelian as well as for common disorders), the development of easier and cheaper molecular techniques, the increasing tendency of physicians to have recourse to genetic tests, by-passing alternative diagnostic procedures, are all factors that contribute to the vast increase in the demand for genetic tests, a demand which is significantly out of step with the available numbers of trained counsellors. This paper discusses possible solutions, including the institution of committees with regulatory powers on genetic testing, the promotion of studies on models of genetic services, on programmes to monitor the services currently offered by test providers, and the expansion of training programmes and of employment opportunities for genetic counsellors.

[The home health care experience in a model chronic, degenerative, genetic pathology: Huntington's disease]. / Riflessioni sull'esperienza di assistenza domiciliare in un modello di patologia genetica, cronico-degenerativa: la Malattia di Huntington.

Home assistance has recently received wide approval among the facilities provided to the individuals suffering from chronic-degenerative diseases. This mode of caring seems to offer both the opportunities to reduce costs and to allow the affected individual to live in a familiar environment. The increasing relevance of genetic diseases in the context of the National Health Service suggested the authors to analyze, by means of an ad hoc questionnaire, the experience of home assistance in a group of families with Huntington's Disease (HD). HD is a chronic, degenerative, genetic disease characterized by neurological and/or mental symptoms. The article underlines the peculiar and complex needs of individuals affected by genetic diseases and of their families.

[Predictive medicine: an ethical challenge to medical practice]. / Medicina predittiva: una sfida etica per la pratica medica.

Predictive genetic tests (predictive medicine) require procedures, norms and attitudes completely different from those used in the everyday clinical practice, as a consequence of some peculiarities of the genome as compared to the universe of biological structures or processes. Some aspects are considered in particular: the relationship between the physician and the potential user of a test and the inadequacy of a directive model based on the criterion of the "benefit for the health"; the requirements and limits of an autonomous choice in predictive testing; the complexities of the balance between social responsibility and individual autonomy for genetic disorders. On the basis of these considerations it is proposed that for predictive testing no one could know about a subject more than he/she wants to know and to tell, limiting the exceptions to well defined cases.

Genetic fitness in Huntington's Disease and Spinocerebellar Ataxia 1: a population genetics model for CAG repeat expansions.

An analysis of genetic fitness was performed in Huntington's Disease (HD) and Spinocerebellar Ataxia 1 (SCA1) families. Two partially overlapping samples were used: clinically defined HD and SCA1 patients from families ascertained in definite geographical areas, and molecularly typed carriers of HD and SCA1 mutations (CAG trinucleotide expansions). In both cases, a control group of normal relatives was used. HD and SCA1 patients born before 1915-20 had more children than normal controls. Carriers of HD and SCA1 mutations, all in the low/medium expansion range (37-49 and 47-54 CAG repeats respectively), had a higher number of children than controls up to more recent times (1935-1950). The reproduction of heterozygotes for large expansions could be analysed only in subjects born after 1950 and provided indirect evidence of a lower than normal number of children. The above results fit a model based on a differential fitness according to the degree of expansion. Such a model predicts that 1) up to relatively recently the frequency of alleles in the low/medium range has been maintained or even increased by the increased fitness of their carriers, as well as by new mutations, and 2) the frequency of large expansions, part of which are lost at each generation, is maintained through further expansions of alleles in the low/medium expansion range. The implications of such a model on linkage disequilibrium and the possible spread of these diseases in future generations are discussed.

Epidemiological and linkage studies on Huntington's disease in Italy.

The results of an epidemiological survey on Huntington's disease in the Lazio Region, Central Italy, and of linkage studies in a subset of families are reported. From a total of 99 ascertained families and 491 patients, a prevalence of 25.6 X 10(-6) was obtained, with distributions of age at onset and age at death similar to those described in the literature. No relationship with the sex of the transmitting parent was observed. Analysis of 10 chromosome 4 restriction fragment length polymorphisms in 11 families showed consistent linkage between the genetic loci D4S10, D4S43 and D4S95, and the disease. A recombination rate of 0.08 for D4S10 markers was obtained in this sample. Allelic frequencies of DNA markers in the general population are also reported.

Psychological aspects of genetic counseling. II: Quantitative analysis of a transcript of a genetic counseling session.

The Bales system of scoring small group interactions was used to analyze a transcript of a preamniocentesis (genetic) counseling session in which a husband (H), wife (W), and a male counselor (C) participated. Scoring required the subdivision of communication into the smallest meaningful and scorable units, assigning each unit one of twelve possible category scores and designating the initiator and intended recipient(s) of the unit. The categories included "positive" and "negative" reactions, questions and attempted answers. Over half the units were found to consist of interactions in which information, orientation, and clarification were provided. C initiated 54% of all units of which three-quarters consisted of factual information regarding amniocentesis, genetic risks, Down syndrome, and mental retardation. C interacted significantly more frequently with W than with H, but units directed toward H were significantly more positive than those toward W. One interaction, in which C responded to affective material, significantly altered the subsequent frequency and direction of units; H became more verbal and there was an increase in further affective expression. Although evidence of persuasion was present, no directiveness was demonstrated. The data show that quantitative study of genetic counseling is feasible. Further research on different counseling styles and on the influence of specific interventions on later outcome has been undertaken.