Predictive DNA-testing for Huntington's disease and reproductive decision making: a European collaborative study

Abstract

This European collaborative study addresses the question whether a predictive test result for Huntington's disease (HD) has an effect on subsequent reproduction by comparing carriers and non-carriers of the Huntington mutation. A unique characteristic of this study is that this evaluation is done in persons at reproductive age who had a predictive test after the identification of the Huntington gene and who were counselled in one of the participating centres. Data were collected for 180 carriers and 271 non-carriers who received a predictive test result in the period 1993 ± 1998 in Aberdeen, Athens, Cardiff, Leiden, Leuven, Paris or Rome. The mean age of the total study group was 31.5 years and for about half of the group the follow-up interval was 3 years or more, with a maximum of 7 years. The collaborative study clearly revealed an overall impact of the predictive test result on subsequent reproduction: 14% of the carriers had one or more subsequent pregnancies vs 28% of the non-carriers. In the total carrier group a prenatal test was carried out in about two thirds of the pregnancies and one child was born after preimplantation genetic diagnosis; artificial insemination by donor, egg cell donation or adoption were not reported. A more refined analysis was performed in the subgroup with a follow-up interval of at least 3 years and who reported`family planning' as a motive to apply for predictive testing in the pretest period. The complexity of this motive is discussed. In this subgroup with a desire for children in the pretest period the effect of the predictive test result was more pronounced: 69% of the non-carriers had subsequent pregnancies while only 39% of the carriers who mentioned`family planning' as one of the major reasons to apply for predictive testing had a subsequent pregnancy. Of the carriers with one or more subsequent pregnancies the percentage using prenatal diagnosis was slightly higher than the percentage not using it, although there were clear differences from one centre to another. The latter group's decisions may seem more intriguing but may be partially understood based on stage theories of health behaviour. Last, but not least, whatever option is chosen by a couple at increased risk of transmitting the Huntington mutation, it is of the utmost importance that professionals fully respect this decision and support the couple.

New tools for preimplantation genetic diagnosis of Huntington's disease and their clinical applications

“…An equal female to male distribution was observed in the at-risk persons whatever type of PND was requested. 15 In their 10-year experience in prenatal testing for HD, Maat-Kievit et al 16 noticed that there were more at-risk female patients in the direct PND testing group and an equal representation in the exclusion test group. Goizet et al 17 noted that significantly more women (63%) than men (37%) requested presymptomatic testing and that even more women (64%) than men (36%) went through the entire procedure and obtained a result.…”

“…The second motive for requesting predictive testing, after ''the relief from uncertainty'', is ''family planning''. 15,17 It would be of interest to know if the availability of a PGD exclusion test affects the percentage of couples who will go through the entire PT procedure.…”

Psychological distress in the 5-year period after predictive testing for Huntington's disease

“…29 In our group of tested persons, the ratio female/male in non-carriers proved to be larger than in carriers. 8 Finally, for a discussion of post-test reproductive decisions, we refer to the results of the European collaborative study 30 on reproductive decisions after predictive testing.…”

Prenatal testing for Huntington's disease: a European collaborative study

“…Another part of the European collaborative study describes the reproductive choices of those who undertook predictive testing. 10 …”