ironXS: high-school screening for hereditary haemochromatosis is acceptable and feasible.

As the results of the Human Genome Project are realised, screening for genetic mutations that predispose to preventable disease is becoming increasingly possible. How and where such screening should best be offered are critical, unanswered questions. This study aimed to assess the acceptability and feasibility of genetic screening for preventable disease, using the model of hereditary haemochromatosis, in high-school students. Screening was offered for the HFE C282Y substitution to 17,638 students. Questionnaires were administered at the time of screening (Q1) and approximately 1 month after results were communicated (Q2). Outcomes assessed were uptake of screening, change in scores of validated anxiety, affect and health perception scales from Q1 to Q2, knowledge and iron indices in C282Y homozygous individuals. A total of 5757 (32.6%) students had screening and 28 C282Y-homozygous individuals (1 in 206) were identified, and none of the 27 individuals who had iron indices measures had significant iron overload. There was no significant change in measures of anxiety, affect or health perception in C282Y homozygous or non-homozygous individuals. Over 86% of students answered each of five knowledge questions correctly at Q1. Genetic population-based screening for a preventable disease can be offered in schools in a way that results in minimal morbidity for those identified at high risk of disease. The results of this study are not only relevant for haemochromatosis, but for other genetic markers of preventable disease such as those for cardiovascular disease and cancer.

A retrospective study of the impact of lifestyle on age at onset of Huntington disease.

In transgenic mouse models of Huntington disease (HD) environmental enrichment significantly delays disease onset. A questionnaire-based survey of 154 adults with diagnosed HD (mean 4.2 years postdiagnosis) and a known IT15 CAG repeat length, explored whether premorbid lifestyle may relate to age-at-onset (AO). Participants were drawn from HD outpatient clinics in Australia and New Zealand. Premorbid physical, intellectual, and passive activity levels were used to generate scores in the categories of leisure, nonleisure (education, occupation and domestic duties) and total lifestyle. AO was associated with increased CAG repeat length as expected (r = -0.72, P < 0.001), but also with a lifestyle that included higher levels of passive activity (r = -0.38, P < 0.001). Multiple linear regression modeling showed lifestyle passivity to be a variable independent of CAG repeat length in predicting AO (R(2) = 0.54, b = -0.22, P = 0.005). Comparison of the mean AO across tertiles of lifestyle passivity scores showed onset 4.6 years (95% CI = 1.3-7.9) later in the least compared with the most passive tertile. CAG repeat length was also shown to predict lifestyle passivity (R(2) = 0.12, b = 1.08, P < 0.0005). Neither intellectual nor physical activity showed significant relationships to AO or CAG repeat length in this cohort. Our study leads to two conclusions: that a passive lifestyle may be a preclinical expression of HD, and that it actually contributes to the earlier onset of symptoms. Overcoming the tendency to be passive may substantially delay onset of HD. (c) 2010 Movement Disorder Society.

Problems assessing uptake of Huntington disease predictive testing and a proposed solution.

The uptake of predictive testing for Huntington disease informs our understanding of decision making by those at risk and assists with planning for service provision. Uptake figures have been reported from several centers based on the total number of people who have undertaken predictive testing as a percentage of those estimated to be at 50% risk in the region. This method produced a figure of 35% from our own service, much higher than observation of the local pedigrees indicated, and higher than other published reports. We have identified some errors in the commonly used formula. The major errors are the use of the cumulative total of those who have had testing with a static denominator of those at 50% risk, and the failure to exclude from the at-risk group those who are too young and therefore ineligible to test.We report data from the Huntington Disease Register of Victoria and estimate the prevalence to be 8 per 100,000 in 1999. Additional data on individuals at risk were collated. We found that for every diagnosed person there were 4.2 individuals at 50% risk, a lower ratio than one to five hypothesized in the literature. We examined these ratios in the context of uptake.Significantly, we provide a solution to the calculation of uptake with a formula that factors in a dynamic denominator and corrects for the number of years testing has been offered. Using this formula, we calculated an uptake of 13.0-15.4% for the state of Victoria, Australia. This formula can be used to compare uptake across different centers.

Fifteen years of experience in predictive testing for Huntington disease at a single testing center in Victoria, Australia.

PURPOSE: This retrospective study describes 15 years of experience in predictive testing for Huntington disease at a single center in Victoria, Australia. METHOD: Data collected on 756 participants included age, gender, family history, prior risk and the age at which this risk became known, exposure to Huntington disease, number of children, and proximity to the testing center. RESULTS: Some 57.8% of participants were female, and 88.8% had a 50% risk of developing Huntington disease. The mean age at entry was 40.4 years and was gender-independent. Of all completed tests (n = 648), 37.5% gave high-risk results, and 3.2% were in the zone of reduced penetrance. The 14.3% who withdrew from testing tended to be younger and childless, lacked exposure to severe Huntington disease, and more often at 25% or less risk. Some 32.4% of candidates presented for testing within 1 year of becoming aware of their risk, and most of these individuals had little or no exposure to severe Huntington disease. Those whose exposure was considerable waited on average for more than 13 years. Among the most inexperienced candidates were a group of "adoptees" (raised away from their biological family). Maternal transmission was the source of risk for 19 of 20 adoptees. CONCLUSION: This study illustrates the significance of exposure to Huntington disease and its impact on the timing of testing.