| 1. |
- Creighton, S, et al.
(författare)
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Predictive, pre-natal and diagnostic genetic testing for Huntington's disease : the experience in Canada from 1987 to 2000.
- 2003
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Ingår i: Clinical Genetics. - 0009-9163 .- 1399-0004. ; 63:6, s. 462-75
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Tidskriftsartikel (refereegranskat)abstract
- Predictive and pre-natal testing for Huntington's Disease (HD) has been available since 1987. Initially this was offered by linkage analysis, which was surpassed by the advent of the direct mutation test for HD in 1993. Direct mutation analysis provided an accurate test that not only enhanced predictive and pre-natal testing, but also permitted the diagnostic testing of symptomatic individuals. The objective of this study was to investigate the uptake, utilization, and outcome of predictive, pre-natal and diagnostic testing in Canada from 1987 to April 1, 2000. A retrospective design was used; all Canadian medical genetics centres and their affiliated laboratories offering genetic testing for HD were invited to participate. A total of 15 of 22 centres (68.2%), currently offering or ever having offered genetic testing for HD, responded, providing data on test results, demographics, and clinical history. A total of 1061 predictive tests, 15 pre-natal tests, and 626 diagnostic tests were performed. The uptake for predictive testing was approximately 18% of the estimated at-risk Canadian population, ranging from 12.5% in the Maritimes to 20.7% in British Columbia. There appears to have been a decline in the rate of testing in recent years. Of the predictive tests, 45.0% of individuals were found to have an increased risk, and a preponderance of females (60.2%) sought testing. A greater proportion of those at < or = 25% risk sought predictive testing once direct CAG mutation analysis had become available (10.9% after mutation analysis vs 4.7% before mutation analysis, p = 0.0077). Very few pre-natal tests were requested. Of the 15 pre-natal tests, 12 had an increased risk, resulting in termination of pregnancy in all but one. Diagnostic testing identified 68.5% of individuals to be positive by mutation analysis, while 31.5% of those with HD-like symptoms were not found to have the HD mutation. The positive diagnostic tests included 24.5% of individuals with no known prior family history of HD.
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| 2. |
- Almqvist, E, et al.
(författare)
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Risk reversals in predictive testing for Huntington disease.
- 1997
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 61:4, s. 945-52
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Tidskriftsartikel (refereegranskat)abstract
- The first predictive testing for Huntington disease (HD) was based on analysis of linked polymorphic DNA markers to estimate the likelihood of inheriting the mutation for HD. Limits to accuracy included recombination between the DNA markers and the mutation, pedigree structure, and whether DNA samples were available from family members. With direct tests for the HD mutation, we have assessed the accuracy of results obtained by linkage approaches when requested to do so by the test individuals. For six such individuals, there was significant disparity between the tests. Three went from a decreased risk to an increased risk, while in another three the risk was decreased. Knowledge of the potential reasons for these changes in results and impact of these risk reversals on both patients and the counseling team can assist in the development of strategies for the prevention and, where necessary, management of a risk reversal in any predictive testing program.
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| 3. |
- Yoon, G., et al.
(författare)
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Autosomal recessive hereditary spastic paraplegia : clinical and genetic characteristics of a well-defined cohort
- 2013
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Ingår i: Neurogenetics. - : Springer Science and Business Media LLC. - 1364-6745 .- 1364-6753. ; 14:3-4, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- We describe the clinical and genetic features of a well-characterized cohort of patients with autosomal recessive hereditary spastic paraplegia (ARHSP) in the province of Ontario. Patients with documented corticospinal tract abnormalities were screened by whole gene sequencing and multiplex ligation probe amplification for mutations in nine genes known to cause ARHSP. Of a cohort of 39 patients, a genetic diagnosis was established in 17 (44 %) and heterozygous mutations were detected in 8 (21 %). Mutations were most frequent in SPG7 (12 patients), followed by SPG11 (10 patients), PNPLA6 (SPG39, 2 patients), and ZFYVE26 (SPG15, 2 patients). Although there are associations between some clinical manifestations of ARHSP and specific genes, many patients are tested at an early stage of the disease when phenotype/genotype correlations are not obvious. Accurate molecular characterization of well-phenotyped cohorts of patients will be essential to establishing the natural history of these rare degenerative disorders to enable future clinical trials.
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