Should we genetically test everyone for haemochromatosis?

Genetic explanations, discrimination and chronic illness: A qualitative study on hereditary haemochromatosis in Germany

OBJECTIVE

The objective of this study is to explore the discriminatory impacts of genetic diagnosis for people living with the chronic illness of hereditary haemochromatosis in Germany.

METHODS

Semi-structured interviews with 15 patients; all had tested positive for a genetic mutation associated with haemochromatosis and already displayed symptoms of the disease. Inductive approach, with interviews collaboratively interpreted by the research group in a vertical and horizontal analysis informed by a multi-person perspective.

RESULTS

First, as the genetic diagnosis of the disease holds the promise of therapeutic intervention, the interviewees perceived it as leading to relief. Second, the interviewees felt stigmatized by their family members, they complained of social isolation and a lack of acknowledgement of their health problems. Third, they feared disadvantages for themselves or their children at their place of work, when buying insurance coverage, and when attempting to donate blood.

DISCUSSION

The findings point to the need for an expanded view on genetic discrimination. Besides institutional discrimination, it appears necessary to systematically address interactional stigmatization and take anxieties and fears into account. Here we see starting points for providing essential support through specialist and self-help groups to those faced with the genetic diagnosis of haemochromatosis in addition to and beyond the legal protection against genetic discrimination that already exists.

The Impact of Test Outcome Certainty on Interest in Genetic Testing Among College Women

Osteoporosis and hemochromatosis are both late-onset preventable diseases, but future genetic tests for these conditions are likely to differ in their predictive abilities. To determine whether interest in a specific genetic test for hemochromatosis would be higher than interest in a theoretical test for osteoporosis susceptibility, undergraduate women at the University of Cincinnati (N = 181) were surveyed regarding their interest in genetic testing for these conditions. The clinical features of the diseases and the limits of a genetic test for each were described. Sixty-three percent of the total population was interested in genetic testing with a trend toward higher interest in the osteoporosis group. Disease familiarity, perceived disease severity, and perceived risk for disease appear to be more important predictors of genetic test acceptance than diagnostic specificity. Suggested implications for the development of population genetic screening tests are discussed.

Asymptomatic individuals at genetic risk of haemochromatosis take appropriate steps to prevent disease related to iron overload

BACKGROUND/AIMS

If community screening for hereditary haemochromatosis is to be considered, compliance with preventative measures and absence of significant psychological morbidity must be demonstrated.

METHODS

Workplace screening for the HFE C282Y mutation and then clinical care for C282Y homozygotes was instituted. Data were collected on understanding of test results, perceived health status and anxiety for C282Y homozygotes compared with controls. Uptake of clinical care, compliance and response to treatment and changes in diet were monitored for up to 4 years for C282Y homozygotes.

RESULTS

After 11 307 individuals were screened, 40/47 (85%) newly identified C282Y homozygotes completed questionnaires 12 months after diagnosis compared with 79/126 (63%) of controls. Significantly more C282Y homozygotes correctly remembered their test result compared with controls (95 vs 51%, P<0.0001). No significant difference in perceived health status was observed within or between the two groups at 12 months compared with baseline. Anxiety levels decreased significantly for C282Y homozygotes at 12 months compared with before testing (P<0.05). Forty-five of the 47 (95.8%) C282Y homozygotes accessed clinical care for at least 12 months. All 22 participants requiring therapeutic venesection complied with treatment for at least 12 months (range 12-47 months).

CONCLUSION

Individuals at a high genetic risk of developing haemochromatosis use clinical services appropriately, maintain their health and are not 'worried well'. Population genetic screening for haemochromatosis can be conducted in the work place in a way that is acceptable and beneficial to participants.

Psychological adjustment and knowledge about hereditary hemochromatosis in a clinic-based sample: a prospective study

This study assessed psychological adjustment and quality of life relative to population-based norms and knowledge about hereditary hemochromatosis in a sample of 101 patients who attended a hemochromatosis clinic. Participants were assessed prior to their clinic visit, and two weeks and 12 months after attendance, using self-administered questionnaires. Mean Mental Health Component Scores from the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) (45.3, 95% CI 43.2, 47.4) were as compromised as those found amongst stroke victims (45.9, 95% CI 42.8, 49.0) who had participated in a national health survey. Recall of the genetic testing result was less than optimal, in that only 69.3% of those with genetic testing results knew whether they carried one or two mutations. This study demonstrates that patients would benefit from routine assessment of psychological distress and referral to mental health professionals of those whose levels of distress suggest a need for clinical intervention. Results also show that patients may benefit from strategies aimed at improving recall of genetic testing results.

Normal iron metabolism and the pathophysiology of iron overload disorders

Iron overload disorders represent a heterogenous group of conditions resulting from inherited and acquired causes. If undiagnosed they can be progressive and fatal. Early detection and phlebotomy prior to the onset of cirrhosis can reduce morbidity and normalise life expectancy. We now have greater insight into the complex mechanisms of normal and disordered iron homeostasis following the discovery of new proteins and genetic defects. Here we review the normal mechanisms and regulation of gastrointestinal iron absorption and liver iron transport and their dysregulation in iron overload states. Advances in the understanding of the natural history of iron overload disorders and new methods for clinical detection and management of hereditary haemochromatosis are also reviewed. The current screening strategies target high-risk groups such as first-degree relatives of affected individuals and those with clinical features suggestive of iron loading. Potential ethical, legal and psychosocial issues arising through application of genetic screening programs need to be resolved prior to implementation of general population screening programs.

Genetic susceptibility screening in schools: attitudes of the school community towards hereditary haemochromatosis

Carrier screening to provide reproductive options has been offered to students in the school setting for a number of years; however, genetic susceptibility screening for disease predisposition has not been introduced to the school community. Experience has shown that the success of a population-based programme relies on the community's acceptance. Therefore, we sought to establish the Australian secondary school community's attitudes towards genetic susceptibility screening in schools, with hereditary haemochromatosis as the model condition with an available prevention. School students, aged 15-18 (n = 748), completed a questionnaire immediately before and following an oral educational presentation. Their parents (n = 179) and staff (n = 89) received written information and returned a questionnaire by post. Semi-structured interviews were with Government representatives. Attitudes towards genetic screening in schools and knowledge of genetic and clinical features of haemochromatosis, as well as the likelihood of accepting a genetic susceptibility test for haemochromatosis, were all measured. Participants were positive about genetic screening for disease susceptibility in schools. Their knowledge was high following education with no significant differences between participants of each group. Sixty-eight percent of students would be likely to have the test if it were offered, with parents and staff, indicating that they would like the students to be offered a test, on average. Genetic susceptibility screening in schools is a novel concept. The results of our study indicate that it could be a public health success with the support of the community.

Demanding pure motives for donation: the moral acceptability of blood donations by haemochromatosis patients

Blood banks all over the world attempt to cover the demand for blood by donations from voluntary non-remunerated donors. The discussion regarding the acceptability of blood donations by haemochromatosis patients focuses on the question of whether health benefits violate the rule of the altruistic donor. Utilitarian and deontological arguments for and against the policy of accepting blood donors who need to let blood regularly in order to stay healthy are considered by this article. A closer look at the procedure reveals that the confusion is due to the conflation of, on the one hand the phlebotomy, and on the other hand, the decision about the destination of the blood afterwards. The health benefits are connected to the phlebotomy and not to the donation. The morally relevant point in the decision as to whether the candidate is a truly altruistic donor is whether he donates without asking for a benefit in return. It is concluded that haemochromatosis patients can be free, voluntary, and altruistic blood donors.

When and how should we screen for hereditary hemochromatosis?

Hemochromatosis is the clinical expression of iron overload and occurs as hereditary and secondary variants. In hereditary hemochromatosis, an inborn error in iron metabolism results in excess absorption of dietary iron, which gradually accumulates in the liver, pancreas, and heart. The most common form of hereditary hemochromatosis is related to homozygosity for the C282Y mutation in the HFE gene. Early diagnosis is essential because hereditary hemochromatosis is common, severe, and treatable. Early manifestations consist of asthenia, arthralgia, and serum transferrin saturation elevation. The C282Y mutation should be looked for to confirm the diagnosis in the patient and family members. Measurement of serum transferrin saturation followed by genetic testing in individuals with values above 45% is a reasonable screening strategy.

Metabolic liver disease in the young adult

This chapter describes the gene mutations, phenotypes, diagnosis and therapy of the common metabolic liver diseases in young adulthood: haemochromatosis, Wilson disease, alpha(1)-anti-trypsin deficiency and cystic fibrosis. The remarkable variability of the phenotypical expression of the mutated genotypes makes screening recommendations and the establishment of prognosis for these liver disorders in young adults problematical. The diagnosis and therapy of the young adult with metabolic liver disease is discussed, with an emphasis on maintaining quality-of-life and balancing the importance of early intervention with the stigmatization of the diagnosis of potentially life-threatening liver disease. There is a critical need for the development of biochemical markers that would predict the risk of expression of clinical phenotypes and prognosis.

Morbidity risk in HFE associated hereditary hemochromatosis C282Y heterozygotes

Hereditary hemochromatosis (HHC) is a late-onset, autosomal recessive disorder leading to a chronic iron overload syndrome, finally causing diabetes, cardiomyopathy and liver disease. HHC is the most common single gene disorder in northern Europeans that occurs with a frequency of approximately 0.5%, and most of these patients carry the C282Y and H63D mutation in the HFE gene on chromosome 6p21.3. The vast majority of HHC patients are homozygous for the C282Y mutation, but HHC phenotypes are observed in other genotypes. Expression of the disease, in those homozygous for the C282Y mutation, is highly variable depending on the various features of the population studied. C282Y heterozygotes have slightly increased iron stores and in absence of other genetic and/or environmental factors do usually not develop the HHC phenotype. It is currently a matter of debate whether C282Y heterozygotes may have an increased risk for morbidity. Different studies investigating the association of C282Y heterozygocity with morbidity have given conflicting results, as is exemplified by extrahepatic cancers, cardiovascular diseases, alcoholic liver disease, and diabetes. However, there are examples of clear and unambiguous disease associations, such as with sporadic pophyria cutanea tarda. It remains to be seen whether a strong correlation between the C282Y heterozygous state and distinct pathological conditions will exist and large-scale genotyping studies will help to identify such potential risk groups in the future.

Acceptance of neonatal genetic screening for hereditary hemochromatosis by informed parents

The aim of this study was to assess attitudes to neonatal genetic screening for hereditary hemochromatosis. A total of 135 consecutive, pregnant women and their partners attending a hospital antenatal clinic in the Australian Capital Territory were given detailed written and verbal information about potential risks and benefits of neonatal genetic screening. Issues such as uncertainty of disease expression, confidentiality, genetic discrimination, and storage of genetic data were addressed. Attitudes were assessed by interview and questionnaire. There was a high level of acceptance for neonatal genetic screening in general (99%) and for hemochromatosis in particular (91.5%). There was no association of prior knowledge of hemochromatosis, family history of hemochromatosis, ethnicity, age, education, or occupation class with nonacceptance. Of the subjects, 39.5% reported feeling "a little anxious" about the prospect of screening their infants, although only 5.4% reported feeling "very anxious." Reasons given for nonacceptance of screening included inability of the child to give informed consent, insufficient evidence that diagnosis of hemochromatosis in childhood is beneficial, risk of discrimination on genetic grounds, lack of agreement between partners, and privacy issues. These data suggest that an Australian neonatal genetic screening program for hemochromatosis is likely to be accepted by this and similar groups of subjects, but there should be an opportunity for parents who object to screening to opt out of any such program.

Estimating the efficacy and efficiency of cascade genetic screening

Screening for genetic variants that predispose individuals or their offspring to disease may be performed at the general population level or may instead be targeted at the relatives of previously identified carriers. The latter strategy has come to be known as "cascade genetic screening." Since the carrier risk of close relatives of known carriers is generally higher than the population risk, cascade screening is more efficient than population screening, in the sense that fewer individuals have to be genotyped per detected carrier. The efficacy of cascade screening, as measured by the overall proportion of carriers detected in a given population, is, however, lower than that of population-wide screening, and the respective inclusion rates vary according to the population frequency and mode of inheritance of the predisposing variants. For dominant mutations, we have developed equations that allow the inclusion rates of cascade screening to be calculated in an iterative fashion, depending upon screening depth and penetrance. For recessive mutations, we derived only equations for the screening of siblings and the children of patients. Owing to their mathematical complexity, it was necessary to study more extended screening strategies by simulation. Cascade screening turned out to result in low inclusion rates (<1%) when aimed at the identification of heterozygous carriers of rare recessive variants. Considerably higher rates are achievable, however, when screening is performed to detect covert homozygotes for frequent recessive mutations with reduced penetrance. This situation is exemplified by hereditary hemochromatosis, for which up to 40% of at-risk individuals may be identifiable through screening of first- to third-degree relatives of overt carriers (i.e., patients); the efficiency of this screening strategy was found to be approximately 50 times higher than that of population-wide screening. For dominant mutations, inclusion rates of cascade screening were estimated to be higher than for recessive variants. Thus, some 80% of all carriers of the factor V Leiden mutation would be detected if screening were to be targeted specifically at first- to third-degree relatives of patients with venous thrombosis. The relative cost efficiency of cascade as compared with population-wide screening (i.e., the overall savings in the extra managerial cost of the condition) is also likely to be higher for dominant than for recessive mutations. This notwithstanding, once screening has become cost-effective at the population level, it can be expected that cascade screening would only transiently represent an economically viable option.

Population screening for hemochromatosis: has the time finally come?

Hemochromatosis refers to a group of common heritable disorders among Western Caucasians which increase susceptibility for development of iron overload and its complications. These consequences are preventable by early detection and simple, relatively inexpensive treatment. Screening of appropriate populations to detect hemochromatosis before iron overload occurs is both effective and cost-effective. The primary goal of screening should be the ongoing detection of persons with hemochromatosis, especially healthy individuals whose risk to develop iron overload is great, in a context that provides appropriate preventive treatment, education, and counseling. Although related issues warrant further study, implementation of well-designed screening programs for hemochromatosis should not be delayed.