Attitudes Regarding Predictive Testing for Retinitis Pigmentosa

Understanding the propensity to undergo genetic testing in patients affected by inherited retinal diseases: a twelve-item questionnaire

BACKGROUND

The diagnosis of inherited retinal diseases (IRDs) can only be confirmed through genetic testing. The aim of our study is to investigate the propensity of Italian patients affected by IRDs to undergo genetic testing.

MATERIALS AND METHODS

One hundred and thirty-two patients diagnosed with IRDs referred to Italian Retina Onlus were enrolled from 1^st January 2021 to 31^th December 2021 in this cross-sectional study to answer to a twelve-item questionnaire.

RESULTS

One hundred and four patients were aware of the possibility of taking a genetic test, and 94 of them did. Most of genetically tested patients (93.6%) had been informed about advantages and limitations of genetic investigations. The most common reason for undergoing genetic testing was to gather information for their relatives, while the most frequent reason for patients not taking the test was lack of someone who encourages them to do so. Most of genetically tested patients believed that the results could aid medical research in the search for a treatment for IRDs, while who did not undergo DNA testing often did not have a clear opinion on the topic. Almost all patients (98.9%) performed the test through the Italian National Health System.

CONCLUSIONS

Our study investigated the tendency of Italian patients affected by IRDs to undergo genetic testing, highlighting the importance of educating both patients and healthcare professionals on this topic.

Broadband activation by white-opsin lowers intensity threshold for cellular stimulation

Photoreceptors, which initiate the conversion of ambient light to action potentials via retinal circuitry, degenerate in retinal diseases such as retinitis pigmentosa and age related macular degeneration leading to loss of vision. Current prosthetic devices using arrays consisting of electrodes or LEDs (for optogenetic activation of conventional narrow-band opsins) have limited spatial resolution and can cause damage to retinal circuits by mechanical or photochemical (by absorption of intense narrow band light) means. Here, we describe a broad-band light activatable white-opsin for generating significant photocurrent at white light intensity levels close to ambient daylight conditions. White-opsin produced an order of magnitude higher photocurrent in response to white light as compared to narrow-band opsin channelrhodopsin-2, while maintaining the ms-channel kinetics. High fidelity of peak-photocurrent (both amplitude and latency) of white-opsin in response to repetitive white light stimulation of varying pulse width was observed. The significantly lower intensity stimulation required for activating white-opsin sensitized cells may facilitate ambient white light-based restoration of vision for patients with widespread photoreceptor degeneration.

Broad-Band Activatable White-Opsin

Currently, the use of optogenetic sensitization of retinal cells combined with activation/inhibition has the potential to be an alternative to retinal implants that would require electrodes inside every single neuron for high visual resolution. However, clinical translation of optogenetic activation for restoration of vision suffers from the drawback that the narrow spectral sensitivity of an opsin requires active stimulation by a blue laser or a light emitting diode with much higher intensities than ambient light. In order to allow an ambient light-based stimulation paradigm, we report the development of a ‘white-opsin’ that has broad spectral excitability in the visible spectrum. The cells sensitized with white-opsin showed excitability at an order of magnitude higher with white light compared to using only narrow-band light components. Further, cells sensitized with white-opsin produced a photocurrent that was five times higher than Channelrhodopsin-2 under similar photo-excitation conditions. The use of fast white-opsin may allow opsin-sensitized neurons in a degenerated retina to exhibit a higher sensitivity to ambient white light. This property, therefore, significantly lowers the activation threshold in contrast to conventional approaches that use intense narrow-band opsins and light to activate cellular stimulation.

Patient attitudes towards prenatal diagnostic testing for inherited retinal disease

OBJECTIVE

To explore factors that influence decision-making in relation to prenatal diagnostic testing (PDT) for inherited retinal disease (IRD).

METHOD

Semi-structured interviews were conducted with 50 adults with IRD, selected from a larger sample to provide a diversity of backgrounds and opinions on genetic testing. Interviews were transcribed verbatim and analysed using thematic analysis.

RESULTS

Mostly participants supported PDT, believing that it would provide information to help them prepare for and plan the future care of the child and the potential for early access to emerging therapies. Opposition to PDT stemmed from its use to justify termination of pregnancy, with participants feeling that it was not justified as they retained a good quality of life despite their visual impairment. Participants raised concerns about the risk of PDT and the accuracy of the results. However, most suggested that it should be available as an option for others, but for specific reasons and not as a part of routine care.

CONCLUSION

The variation in attitudes towards PDT and uncertainty about the risk and accuracy of results suggest that individuals at risk of having a child with IRD should have access to genetic counselling to support decision making.

Broad spectral excitation of opsin for enhanced stimulation of cells

Optical stimulation of cells expressing light-sensitive proteins (opsins) has allowed targeted activation with cellular specificity. However, since narrow-band light has been used for excitation of these optogenetic probes, only active stimulation strategies are being attempted for clinical applications such as restoration of vision. Here, we report use of broad spectral excitation (white light) for optogenetic stimulation of opsin-sensitized cells. We found that ReaChR is optimally excited with white light offering significantly higher photocurrents compared to spectrally filtered narrow-band light stimulation. Our findings open up the possibility of passive stimulation strategy by use of natural sunlight for retinal stimulation, which could have benefits for ambient light stimulated vision restoration.

Optical Techniques in Optogenetics

Optogenetics is an innovative technique for optical control of cells. This field has exploded over the past decade or so and has given rise to great advances in neuroscience. A variety of applications both from the basic and applied research have emerged, turning the early ideas into a powerful paradigm for cell biology, neuroscience and medical research. This review aims at highlighting the basic concepts that are essential for a comprehensive understanding of optogenetics and some important biological/biomedical applications. Further, emphasis is placed on advancement in optogenetics-associated light-based methods for controlling gene expression, spatially-controlled optogenetic stimulation and detection of cellular activities.

Perceptions and understanding of genetics and genetic eye disease and attitudes to genetic testing and gene therapy in a primary eye care setting

BACKGROUND

Genetic eye pathology represents a significant percentage of the causes of blindness in industrialized countries. This study explores the level of understanding and perceptions of genetics and inherited eye diseases and the attitudes to genetic testing and gene therapy.

METHODS

The study was conducted in two parts. Participant groups included were: undergraduate students of optometry, primary eye care professionals and members of the general public. A preliminary study aimed to understand perceptions and to explore the level of knowledge about genetics in general, eye genetics and gene therapy. A second survey was designed to explore attitudes to genetic testing and gene therapy.

RESULTS

The majority of participants (82%) perceived genetics as an important science. However, none of them showed a high level of understanding of genetics and inherited eye diseases. Undergraduate students and primary eye care professionals were better informed about inherited eye diseases than the general public (p = 0.001). The majority (80%) across all three groups had a positive attitude to genetic testing and gene therapy. There was a lack of knowledge about the genetic services available among all groups of participants.

CONCLUSION

This calls for serious thinking about the level of dissemination of information about genetics and inherited eye diseases. It shows a broadly supportive attitude to genomic medicine among the public. Improving public awareness and education in inherited eye diseases can improve the utility of genetic testing and therapy.

Should patients with ocular genetic disorders have genetic testing?

PURPOSE OF REVIEW

To discuss the risks, benefits and value of genetic testing for ocular genetic disease.

RECENT FINDINGS

Testing for ocular genetics diseases is becoming more available and successful gene therapy is being reported. Clinicians must prepare for this trend by considering diagnostic genetic testing for their patients.

SUMMARY

As advances continually occur in genetic testing for ocular genetic disorders, clinicians must develop an understanding of the potential risks and benefits for their patients.

Willingness to pay for genetic testing for inherited retinal disease

This paper investigates the willingness of adults with inherited retinal disease to undergo and pay for diagnostic genetic testing in three hypothetical scenarios and to explore the factors that influence decision making. Fifty patients were presented with three scenarios whereby genetic testing provided increasing information: confirming the diagnosis and inheritance pattern alone, providing additional information on future visual function, and identifying in addition a new treatment which could stabilise their condition. Willingness to pay (WTP) was elicited using an iterative bidding game. Regression analysis was used to investigate the probability of agreeing to and paying for testing. Qualitative data were also reviewed to provide a comprehensive understanding of WTP and decision making. The majority of participants agreed to undergo genetic testing in each of the three scenarios. Scenario 2 was the least acceptable with 78% of participants agreeing to genetic testing. The probability of agreeing to genetic testing decreased with age. Between 72 and 96% of participants reported a WTP for genetic testing. Average WTP was £539, £1516, and £6895 for scenarios 1, 2, and 3 respectively. Older participants and participants with higher incomes were willing to pay more for testing. Qualitative data provided additional detail about the rationale behind participants' decisions. The study suggests that patients with inherited retinal disease were willing to undergo and to pay for diagnostic genetic testing, suggesting that they valued the information it may provide. However, several patients preferred not to receive prognostic information and were less willing to pay for genetic testing that yielded such detail.

Current understanding of genetics and genetic testing and information needs and preferences of adults with inherited retinal disease

Advances in sequencing technology and the movement of genetic testing into all areas of medicine will increase opportunities for molecular confirmation of a clinical diagnosis. For health-care professionals without formal genetics training, there is a need to know what patients understand about genetics and genetic testing and their information needs and preferences for the disclosure of genetic testing results. These topics were explored during face-to-face interviews with 50 adults with inherited retinal disease, selected in order to provide a diversity of opinions. Participants had variable understanding of genetics and genetic testing, including basic concepts such as inheritance patterns and the risk to dependents, and many did not understand the term 'genetic counselling'. Most were keen for extra information on the risk to others, the process for genetic testing and how to share the information with other family members. Participants were divided as to whether genetic testing should be offered at the time of the initial diagnosis or later. Many would prefer the results to be given by face-to-face consultation, supplemented by further information in a format accessible to those with visual impairment. Health-care professionals and either leaflets or websites of trusted agencies were the preferred sources of information. Permission should be sought for disclosure of genetic information to other family members. The information needs of many patients with inherited retinal disease appear to be unmet. An understanding of their information needs and preferences is required to help health-care professionals provide optimal services that meet patient expectations.

"To perpetuate blindness!": attitudes of UK patients with inherited retinal disease towards genetic testing

Availability and accuracy of genetic testing in ophthalmology has increased yet the benefits are unclear especially for those conditions where cure or treatments are limited. To explore attitudes to and patients' understanding of possible advantages and disadvantages of genetic testing for inherited retinal disease, we undertook focus groups in three West Yorkshire towns in the UK. Most of our participants had retinitis pigmentosa and one of the focus groups consisted of participants from (British) Asian ethnic background. Here, we report only those attitudes which were common in all three focus groups. Some of the attitudes have already been reported in the literature. Novel findings include attitudes held towards informed choice and life planning, particularly among more severely affected participants. For example, participants appreciated that genetic testing increases informed choice and enables life planning, but these understandings tended to be in a specific sense: informed choice whether to have children and family planning in order to prevent illness recurrence. We conclude that even though these patients are not a homogeneous group, their attitudes tend to be underpinned by deep anxiety of passing their visual impairment onto their children. In this respect, they differ importantly from a small minority of the deaf who would prefer to have children with hearing loss, and from the more general population who do not believe that blindness is a "severe" enough disability to warrant avoiding having children.

Understanding of and attitudes to genetic testing for inherited retinal disease: a patient perspective

Background/aims

The views of people with inherited retinal disease are important to help develop health policy and plan services. This study aimed to record levels of understanding of and attitudes to genetic testing for inherited retinal disease, and views on the availability of testing.

Methods

Telephone questionnaires comprising quantitative and qualitative items were completed with adults with inherited retinal disease. Participants were recruited via postal invitation (response rate 48%), approach at clinic or newsletters of relevant charitable organisations.

Results

Questionnaires were completed with 200 participants. Responses indicated that participants’ perceived understanding of genetic testing for inherited retinal disease was variable. The majority (90%) considered testing to be good/very good and would be likely to undergo genetic testing (90%) if offered. Most supported the provision of diagnostic (97%) and predictive (92%) testing, but support was less strong for testing as part of reproductive planning. Most (87%) agreed with the statement that testing should be offered only after the individual has received genetic counselling from a professional. Subgroup analyses revealed differences associated with participant age, gender, education level and ethnicity (p<0.02). Participants reported a range of perceived benefits (eg, family planning, access to treatment) and risks (eg, impact upon family relationships, emotional consequences).

Conclusions

Adults with inherited retinal disease strongly support the provision of publicly funded genetic testing. Support was stronger for diagnostic and predictive testing than for testing as part of reproductive planning.

Valuing the benefits of genetic testing for retinitis pigmentosa: a pilot application of the contingent valuation method

BACKGROUND

Technological advances present an opportunity for more people with, or at risk of, developing retinitis pigmentosa (RP) to be offered genetic testing. Valuation of these tests using current evaluative frameworks is problematic since benefits may be derived from diagnostic information rather than improvements in health. This pilot study aimed to explore if contingent valuation method (CVM) can be used to value the benefits of genetic testing for RP.

METHODS

CVM was used to elicit willingness-to-pay (WTP) values for (1) genetic counselling and (2) genetic counselling with genetic testing. Telephone and face-to-face interviews with a purposive sample of individuals with (n=25), and without (n=27), prior experience of RP were used to explore the feasibility and validity of CVM in this context.

RESULTS

Faced with a hypothetical scenario, the majority of participants stated that they would seek genetic counselling and testing in the context of RP. Between participant groups, respondents offered similar justifications for stated WTP values. Overall stated WTP was higher for genetic counselling plus testing (median=£524.00) compared with counselling alone (median=£224.50). Between-group differences in stated WTP were statistically significant; participants with prior knowledge of the condition were willing to pay more for genetic ophthalmology services.

CONCLUSIONS

Participants were able to attach a monetary value to the perceived potential benefit that genetic testing offered regardless of prior experience of the condition. This exploratory work represents an important step towards evaluating these services using formal cost-benefit analysis.

Understanding the impact of genetic testing for inherited retinal dystrophy

The capability of genetic technologies is expanding rapidly in the field of inherited eye disease. New genetic testing approaches will deliver a step change in the ability to diagnose and extend the possibility of targeted treatments. However, evidence is lacking about the benefits of genetic testing to support service planning. Here, we report qualitative data about retinal dystrophy families' experiences of genetic testing in United Kingdom. The data were part of a wider study examining genetic eye service provision. Twenty interviewees from families in which a causative mutation had been identified by a genetic eye clinic were recruited to the study. Fourteen interviewees had chosen to have a genetic test and five had not; one was uncertain. In-depth telephone interviews were conducted allowing a thorough exploration of interviewees' views and experiences of the benefits of genetic counselling and testing. Transcripts were analysed using thematic analysis. Both affected and unaffected interviewees expressed mainly positive views about genetic testing, highlighting benefits such as diagnostic confirmation, risk information, and better preparation for the future. Negative consequences included the burden of knowledge, moral dilemmas around reproduction, and potential impact on insurance. The offer of genetic testing was often taken up, but was felt unnecessary in some cases. Interviewees in the study reported many benefits, suggesting genetic testing should be available to this patient group. The benefits and risks identified will inform future evaluation of models of service delivery. This research was part of a wider study exploring experiences of families with retinal dystrophy.

Ethical issues in ocular genetics

PURPOSE OF REVIEW

To review some of the major issues in ophthalmic genetics ethics: predictive testing, prenatal testing and abortion, gene therapy, confidentiality, payment for genetic testing, the duty to recontact patients and convey new information.

RECENT FINDINGS

Patients and families may perceive benefits even though genetic testing may be associated with adverse psychosocial outcomes. Most patients were in favor of prenatal diagnosis but opposed abortion. Patient selection as candidates for gene therapy should be based on the different clinical characteristics of each hereditary disease. The balance between the right of the patient for confidentiality and the best interest of family members or society is an ethical challenge. Most insurance companies will pay for genetic testing if the condition is hereditary. The duty to recontact patients when new medical information becomes available is still ethically controversial.

SUMMARY

The field of ocular genetics is ever growing involving complex medical, technical, financial and social issues. As a result, ethical issues are expected to become more common. Properly prepared medical professionals as well as unique counseling for participants and families may enable improved decision-making taking into consideration the needs of each individual.

Genetic counseling and genetic testing in ophthalmology

PURPOSE OF REVIEW

To introduce the issues specific to the genetic counseling profession for genetic eye diseases.

RECENT FINDINGS

To discuss current issues in ocular genetic counseling including the use of a focused ophthalmology pedigree, informed consent in the blind population, genetic testing trends and psychosocial issues.

SUMMARY

Introduce the time-consuming issues to be addressed in genetic counseling for genetic eye disease patients.