Sir,

Inherited retinal diseases are an important cause of congenital and acquired visual disability.1 Over the last decade, there has been an exponential increase in the number of genes implicated in inherited retinal disease, and currently >200 genes and loci are known to be involved (http://www.sph.uth.tmc.edu/Retnet/home.htm). Genetic testing for inherited retinal disease offers a number of potential benefits and there is enthusiasm for testing among clinicians.2, 3 With the increasing availability of genetic testing for inherited retinal diseases, the views of those affected and their relatives are important, but are rarely sought.4 We conducted a pilot survey of delegates at the national conference of the Retina Awareness Group in 2009 to explore current attitudes to genetic testing for inherited retinal disease.

Materials and methods

A structured questionnaire, with a five-point Likert scale, was given to delegates to assess the motivation behind and attitudes to the availability of genetic testing for inherited retinal diseases. Motivation was assessed with a stem question and six different scenarios, and attitudes on the availability of testing were recorded for seven different scenarios using a second stem question. Responses were classified as being in favour or supportive of, against, or having no preference for genetic testing in each situation. The project was approved by the Leeds Institute for Health Sciences Research Ethics sub-committee.

Results

Completed questionnaires were received from 36 of 83 delegates (43%). Information on the respondents is given in Table 1.

Table 1 Demographic data of respondents
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Respondents were in favour of diagnostic genetic testing for a number of reasons. Testing was most strongly supported for the following reasons: if it could identify a novel treatment (89% in favour), help in understanding the cause of the visual disability (81%), confirm the way the condition was inherited (78%), and predict future visual function (75%) (Table 2).

Table 2 Attitudes to genetic testing for inherited retinal disease (N=36)
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Respondents felt that genetic testing should be available to all those affected (92% in favour) and also to unaffected relatives (78%). The majority also believed that it should be made available only after genetic counselling (72%). Less than half felt that testing should be offered before in vitro fertilisation (42% in favour) or to pregnant women (47%). Only 25 and 17% of respondents felt that genetic testing for inherited retinal disease should be restricted to adults or to those cases when it would identify a novel treatment, respectively (Table 2).

Compared with the respondents without biological children, those with children were less supportive of genetic testing being restricted to adults (16% vs 35%) and offered to pregnant women (42% vs 53%). The group with children was more supportive of testing being available before IVF (47% vs 35%). These differences did not reach statistical significance (Table 3).

Table 3 Attitudes to genetic testing according to parental status
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Discussion

In this study, multiple factors were found to influence the decision to access genetic testing for inherited retinal disease. Although the chance to identify a novel treatment was the strongest motivating factor, it was one of the several factors that were identified as being important and only 17% of respondents believed that testing should be restricted to cases when it may identify a treatment. Our results are in keeping with those of Pawlowitzki et al.5 Even though that study reported in 1986, 95% of respondents wanted genetic research to continue to improve treatment, provide a more accurate or earlier diagnosis, and to identify carriers.

This study found that service users strongly support both diagnostic and predictive testing for inherited retinal disease, but are less supportive of pre-implantation genetic diagnosis and of genetic testing during pregnancy. An earlier survey of an autosomal dominant retinitis pigmentosa (RP) cohort also identified support for predictive testing among both affected and unaffected individuals.6 However, in that study, support for prenatal testing was more common in unaffected siblings (67%) than in those affected (44%). Furthermore, 70 and 75% of respondents felt that they would continue with the pregnancy even if the prenatal test identified that the unborn child would eventually develop RP. High levels of support for prenatal testing (60–65%) have also been identified in other surveys of patients with RP and other inherited retinal diseases and their relatives.5, 7

Genetic testing for inherited retinal disease among children is controversial.4 In this study, there were small differences between the respondents with and without children. Those with biological children were less supportive of restricting genetic testing to adults and of offering pre-natal testing to pregnant women. The same group was, however, more supportive of pre-implantation genetic diagnosis. Emotional distress has been reported by almost 60% of adults who underwent predictive genetic testing as children, yet most were still in favour of predictive testing.6 Given the small number of unaffected relatives or carers in our sample, we were unable to do a similar analysis of opinions based on affected or unaffected status.

Although most respondents in this study supported genetic testing for inherited retinal disease, the majority felt that it should be offered only after counselling by healthcare professionals. Such counselling is important to address the concerns of those being tested and to ensure that the results and limitations of testing are understood.8, 9 It may also ensure that affected individuals retain contact with at least one member of a team of professionals and are offered ongoing support and guidance, particularly while visual function deteriorates.9

Individuals with inherited retinal disease and their relatives or carers are in favour of genetic testing for a number of reasons and despite the fact that most inherited retinal diseases remain untreatable. The majority of respondents support diagnostic and predictive testing in both adults and children, but want counselling before testing. In view of these findings, it is hoped that there will be greater access to testing to bring the service provision into line with the aspirations of service users.