Genetic Counselling for Predictive Testing in Huntington's Disease in One Centre since 1993. Gender-Specific Aspects of Decision-Making.
BACKGROUND
The discovery of the mutation causing Huntington's disease (HD) in 1993 allowed direct mutation analysis and predictive testing to identify currently unaffected carriers with a sensitivity and specificity of virtually 100%.


OBJECTIVE
The present study was designed to comprehensively profile the participants who sought predictive testing for HD between 1993 and 2009 in our Huntington centre.


METHODS
Using a retrospective design, we analysed the written documentation of the counselling sessions for all referrals for predictive mutation testing in this time span. Six hundred sixty-three individuals at risk for HD requested predictive testing. Roughly half (n = 333) completed the protocol and received their test result.


RESULTS
In general our findings are in accordance with other reports: most participants share an a priori risk of 50% (91.1%); more females request testing (58.5%); and those who ask for the result are mostly in their 30 s (mean = 35.1 years). Of those at 50% or 25% prior risks, 47.4% and 22.7%, respectively, tested positive in accordance with the respective risk of inheriting HD. Generally, more participants with an affected mother than father sought genetic testing (52.5% versus 47.5%). Interestingly, this difference was especially evident in the group of females who finally withdrew from testing (59.1%, p = 0.040). Men, in particular those who decided in favour of the test, were more often accompanied by their partner in the pre-test counselling session than vice versa (67.9% versus 44.7%, p = 0.003). On the other hand, significantly more men who were being tested did not have a companion in the pre-test session as compared with men who decided against the test (40.0% versus 25.7%, p = 0.012). During the first four years of predictive testing (1993–1996) more participants completed the protocol and received their test result as in later years. Yet, in this early time span significantly fewer females finally decided in favour of the test (48.4%, p = 0.005). These findings are discussed longitudinally and in the context of the experience in other centres.


CONCLUSIONS
We present new gender-specific aspects of decision-making for predictive HD tests.
Huntington centre NRW, Department of Human Genetics, Ruhr-University, Bochum, Germany.
Larissa
L
Arning
Constantin N
CN
Witt
Jörg T
JT
Epplen
Susanne
S
Stemmler
D000328:Adult; D003657:Decision Making; D004522:Educational Status; D005260:Female; D005817:Genetic Counseling / Q000706:statistics & numerical data*; D005820:Genetic Testing / Q000706:statistics & numerical data*; D005858:Germany; D006801:Humans; D006816:Huntington Disease / Q000175:diagnosis / Q000235:genetics*; D008297:Male; D017533:Marital Status; D008875:Middle Aged; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012737:Sex Factors; D055815:Young Adult