Benjamin C M, Lashwood A
Merseyside and Cheshire Clinical Genetics Service, Liverpool, UK.
Clin Genet. 2000 Jul;58(1):41-9. doi: 10.1034/j.1399-0004.2000.580107.x.
Between 1994 and 1998, the 23 UK genetics departments, which form the UK Huntington's Disease Consortium, have undertaken 161 direct mutation adult predictive tests on individuals whose at-risk parent was alive or had died without showing signs of Huntington's disease (HD) (5.7% of total UK tests). This study describes the number of requests for 25% risk predictive testing for HD in 1994 (the first year in which direct testing was available in the UK), and also a descriptive survey of the first 85 tests. In total, 85 tests were performed in the first 2 years of direct mutation testing, ten (11.8%) tests were mutation positive, 73 (85.91%) were negative and two (2.3%) were equivocal. The at-risk parent was alive in 54 (63.5%) cases. Four of the ten mutation positive candidates had parents who were alive and therefore received a prediction through their child. All centres included a discussion about the effect of testing on the 50% at-risk parent and all offered to see the parent for counselling. Of the 87 applicants for testing during 1994, 31 (35.6%) withdrew, this is higher than the 25% withdrawal rate for the 50% risk candidates. The candidates who withdrew were significantly younger and had more parents who were alive than those who continued with testing. Seven of the 31 candidates who withdrew from testing had at-risk parents who decided to be tested in the first instance. During the counselling process, issues were raised relating to pre-test agreements and family secrecy. This study indicates the importance of pre-test counselling and the involvement of the parent in the counselling process. 25% risk testing for HD is now being offered in the majority of UK centres. As more genes are identified for late-onset conditions, it is important that the complexities of 25% risk testing for late-onset conditions are not underestimated. This limited survey does not investigate how individual families cope with the psychological and social issues raised by this study and further research in this area is needed.
1994年至1998年间，组成英国亨廷顿舞蹈症协会的23个英国遗传学部门，对其患病风险高的父母健在或已去世但未表现出亨廷顿舞蹈症（HD）症状的个体进行了161次直接突变成人预测性检测（占英国总检测数的5.7%）。本研究描述了1994年（英国开始进行直接检测的第一年）对HD进行25%风险预测性检测的申请数量，还对最初的85次检测进行了描述性调查。在直接突变检测的头两年共进行了85次检测，其中10次（11.8%）检测结果为突变阳性，73次（85.91%）为阴性，2次（2.3%）结果不明确。患病风险高的父母健在的情况有54例（63.5%）。10名突变阳性候选者中有4人的父母健在，因此通过其子女获得了预测结果。所有中心都讨论了检测对50%患病风险高的父母的影响，并且都提出为父母提供咨询服务。在1994年申请检测的87人中，31人（35.6%）退出了检测，这一比例高于50%风险候选者25%的退出率。退出检测的候选者明显更年轻，健在的父母也更多。31名退出检测的候选者中有7人的患病风险高的父母最初决定接受检测。在咨询过程中，出现了与检测前协议和家庭保密相关的问题。本研究表明了检测前咨询以及父母参与咨询过程的重要性。目前英国大多数中心都提供HD的25%风险检测。随着更多与迟发性疾病相关的基因被发现，重要的是不要低估迟发性疾病25%风险检测的复杂性。这项有限的调查并未研究各个家庭如何应对本研究提出的心理和社会问题，因此该领域需要进一步研究。
