Abstract We describe the rationale, development, and usability testing for an integrated e‐learning tool and decision aid for parents facing decisions about genome‐wide sequencing (GWS) for their children with a suspected genetic condition. The online tool, DECIDE, is designed to provide decision‐support and to promote high quality decisions about undergoing GWS with or without return of optional incidental finding results. DECIDE works by integrating educational material with decision aids. Users may tailor their learning by controlling both the amount of information and its format – text and diagrams and/or short videos. The decision aid guides users to weigh the importance of various relevant factors in their own lives and circumstances. After considering the pros and cons of GWS and return of incidental findings, DECIDE summarizes the user's responses and apparent preferred choices. In a usability study of 16 parents who had already chosen GWS after conventional genetic counselling, all participants found DECIDE to be helpful. Many would have been satisfied to use it alone to guide their GWS decisions, but most would prefer to have the option of consulting a health care professional as well to aid their decision. Further testing is necessary to establish the effectiveness of using DECIDE as an adjunct to or instead of conventional pre‐test genetic counselling for clinical genome‐wide sequencing.
The number of adolescents who are diagnosed with a genetic disorder is increasing as genome sequencing becomes the standard of clinical diagnostic testing. However, the experience of receiving a diagnosis of a genetic condition has not been extensively studied in adolescents.To identify how adolescents with a genetic condition engage with genetic or genomic counseling services as well as interpret, adapt to, and experience their diagnosis.A literature search of MEDLINE, Embase, CINAHL, and PsycINFO was undertaken. Articles (primary literature, knowledge syntheses, and gray literature) in English that investigated the experiences of adolescents between 10 and 19 years of age who received genetic or genomic counseling were included. Data were extracted from 45 eligible articles and analyzed descriptively.A total of 45 studies were included, most of which were quantitative in nature (21 of 45 [47%]) and conducted in the US (n = 13), followed by the UK (n = 8), Australia (n = 8), and Canada (n = 6). A total of 29 distinct monogenic disorders were investigated. Sample sizes ranged from 1 to 930, with a median of 23 participants, and the year of publication ranged from 1977 to 2019. Included studies addressed all aspects of genetic counseling, but a preponderance of articles assessed knowledge about genetic conditions (n = 17) and challenges of communication within families (n = 16). Fewer articles addressed the experiences of adolescents adapting to their genetic conditions (n = 8) and the genetic counseling process (n = 4). Only 1 study addressed any aspect of genetic counseling in relation to genome sequencing.This scoping review found that most of the included studies focused on adolescents' knowledge about their genetic condition and communication about genetic risks, whereas fewer studies explored their adaptation to the condition and the genetic counseling process. A systematic reconsideration of the genetic counseling process may be undertaken to provide an evidence-informed health care service that is tailored to the needs of this adolescent population.
Abstract Renpenning syndrome (OMIM: 309500) is a rare X‐linked disorder that causes intellectual disability, microcephaly, short stature, a variety of eye anomalies, and characteristic craniofacial features. This condition results from pathogenic variation of PQBP1 , a polyglutamine‐binding protein involved in transcription and pre‐mRNA splicing. Renpenning syndrome has only been reported in affected males. Carrier females do not usually have clinical features, and in reported families with Renpenning syndrome, most female carriers exhibit favorable skewing of X‐chromosome inactivation. We describe a female with syndromic features typical of Renpenning syndrome. She was identified by exome sequencing to have a de novo heterozygous c.459_462delAGAG mutation in PQBP1 (Xp11.23), affecting the AG hexamer in exon 4, which is the most common causative mutation in this syndrome. Streaky hypopigmentation of the skin was observed, supporting a hypothesized presence of an actively expressed, PQBP1 mutation‐bearing X‐chromosome in some cells. X‐inactivation studies on peripheral blood cells demonstrated complete skewing in both the proband and her mother with preferential inactivation of the maternal X chromosome in the child. We demonstrated expression of the PQBP1 mutant transcript in leukocytes of the affected girl. Therefore, it is highly likely that the PQBP1 mutation arose from the paternal X chromosome.
Array genomic hybridization is being used clinically to detect pathogenic copy number variants in children with intellectual disability and other birth defects. However, there is no agreement regarding the kind of array, the distribution of probes across the genome, or the resolution that is most appropriate for clinical use.We performed 500 K Affymetrix GeneChip array genomic hybridization in 100 idiopathic intellectual disability trios, each comprised of a child with intellectual disability of unknown cause and both unaffected parents. We found pathogenic genomic imbalance in 16 of these 100 individuals with idiopathic intellectual disability. In comparison, we had found pathogenic genomic imbalance in 11 of 100 children with idiopathic intellectual disability in a previous cohort who had been studied by 100 K GeneChip array genomic hybridization. Among 54 intellectual disability trios selected from the previous cohort who were re-tested with 500 K GeneChip array genomic hybridization, we identified all 10 previously-detected pathogenic genomic alterations and at least one additional pathogenic copy number variant that had not been detected with 100 K GeneChip array genomic hybridization. Many benign copy number variants, including one that was de novo, were also detected with 500 K array genomic hybridization, but it was possible to distinguish the benign and pathogenic copy number variants with confidence in all but 3 (1.9%) of the 154 intellectual disability trios studied.Affymetrix GeneChip 500 K array genomic hybridization detected pathogenic genomic imbalance in 10 of 10 patients with idiopathic developmental disability in whom 100 K GeneChip array genomic hybridization had found genomic imbalance, 1 of 44 patients in whom 100 K GeneChip array genomic hybridization had found no abnormality, and 16 of 100 patients who had not previously been tested. Effective clinical interpretation of these studies requires considerable skill and experience.
Adult predictive and prenatal testing programmes for Huntington's disease (HD) in Canada have been available since 1986. However, the demand for prenatal testing and the reasons why some people choose not to have the prenatal test for this late onset disorder have not been well documented. In addition, the knowledge and attitudes of adult predictive testing candidates and their partners about prenatal testing are not well known nor are the psychological effects of prenatal testing well understood. As of September 1991, 425 subjects had entered the Canadian Collaborative Study of Predictive Testing and, of these, 47 subjects or their partners had become pregnant. Of this group, 14 (30%) couples requested prenatal testing, 24 (51%) couples did not want prenatal testing, and nine (19%) at risk subjects had already received a decreased risk through adult predictive testing and, therefore, were not eligible for the prenatal test. Of the 14 couples who initially requested prenatal testing, seven withdrew. Thus, demand for the prenatal test by eligible candidates was 7/38 or 18%, which is much lower than the 32 to 65% expected based on early survey data. The most frequently cited reason for declining prenatal testing was the hope that a cure would be found in time for their children. While the majority of adult predictive testing candidates (71%) in our study had accurate information about definitive prenatal testing, many (63%) did not have a correct understanding of exclusion prenatal testing. Although no serious adverse events such as suicide planning or admission to psychiatric hospital have occurred, a particular need for careful counselling was identified for those at risk candidates and their partners who have one prenatal test and feel compelled to use the test again in future pregnancies. Even though prenatal testing for HD is not requested as often originally expected, it still remains a desired option for some at risk persons and their partners.
There are several unresolved challenges associated with the clinical application of genome-wide sequencing technologies. One of the most discussed issues is incidental findings (IF), which are defined as discoveries made as a result of genetic testing that are unrelated to the indication for the test. The discussion surrounding IF began in the context of research, which we have used to frame consideration of IF in the clinical context. There is growing consensus that analytically valid and medically actionable IF should be offered to patients, but whether and to what extent clinicians should disclose other kinds of IF is debated. While others have systematically reviewed the literature concerning genetic IF, previous reviews focus on ethical and research-related issues and do not consider the implications for the genetic counseling profession specifically. This review discusses the practical considerations, ethical concerns and genetic counseling issues related to IF, with a particular focus on clinical genome-wide sequencing. To date, the bulk of the literature with respect to IF in the clinical context consists of commentaries, reviews and case reports. There is a need for more empirical studies to provide a foundation for institutional protocols and evidence-based clinical practice standards.
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