Partners of mutation-carriers for Huntington's disease: forgotten persons?

This study focuses on psychological distress and coping strategies in partners of tested persons 5 years after predictive testing for Huntington's disease. A total of 16 carrier-couples and 17 noncarrier-couples participated in the study. Self-report questionnaires were used, assessing depression level, anxiety, intrusive and avoidance thoughts and coping strategies. Partners of carriers have as much distress as carriers, and for some distress variables even more (P<0.05-0.001). They clearly experience more psychological distress than noncarriers' partners, as expected (P<0.05-0.001). Regarding coping strategies, carriers' partners adopt more passive strategies (passive-regressive and avoiding reactions; P<0.05) and less active strategies (social support seeking and problem solving; P<0.05-0.001), compared to carriers. For both carriers and partners, the adoption of more passive strategies for coping was associated with more distress and the use of more active strategies with less distress (for carriers: P<0.05-0.001; for carriers' partners: P<0.05). The presence of children before predictive testing was an additional result-specific distress factor in carriers and their partners. In conclusion, carriers' partners have at least as much psychological distress as carriers, but partners have the tendency to draw back. The results suggest that the grief of carriers' partners may be 'disenfranchised', or not socially recognised, as if they have no right to mourn. We moreover interpreted the results referring to concepts such as anticipatory grief, psychological defences, dissonance processes and imbalanced partner relationship. Finally, we formulated some implications for genetic counselling.     

Huntington's disease: do future physicians and lawyers think eugenically?

The availability of presymptomatic and prenatal genetic tests could give rise to societal pressures on persons at risk for Huntington's disease (HD). The objective of this study was to identify future lawyers' and physicians' views on eugenics and genetic testing for HD. Five-hundred and ninety-nine Swiss law students and advanced medical students from 11 courses received teaching about HD and patient autonomy. They filled out questionnaires after having seen an audio/video recording of an interview with an HD mutation carrier. Participation rates were 68-97%. Attitudes of future lawyers and physicians were significantly different for most questions: 73.2% of law students vs 39.4% of medical students agreed that society should do everything possible to diminish the frequency of HD, including non-governmental pressure on carriers to undergo systematic genetic testing and recommendation of sterilization; 94% of all students agreed to the systematic proposal of prenatal testing to all women at risk; and 83.4% of medical students, but only 40.3% of law students, agreed that the wishes of a person at risk not to have her/himself and future children tested must be entirely respected. More education is needed to discourage eugenic pressures and discrimination of persons at risk of HD and other genetic diseases.     

α-Synuclein levels modulate Huntington's disease in mice

α-Synuclein and mutant huntingtin are the major constituents of the intracellular aggregates that characterize the pathology of Parkinson's disease (PD) and Huntington's disease (HD), respectively. α-Synuclein is likely to be a major contributor to PD, since overexpression of this protein resulting from genetic triplication is sufficient to cause human forms of PD. We have previously demonstrated that wild-type α-synuclein overexpression impairs macroautophagy in mammalian cells and in transgenic mice. Overexpression of human wild-type α-synuclein in cells and Drosophila models of HD worsens the disease phenotype. Here, we examined whether α-synuclein overexpression also worsens the HD phenotype in a mammalian system using two widely used N-terminal HD mouse models (R6/1 and N171-82Q). We also tested the effects of α-synuclein deletion in the same N-terminal HD mouse models, as well as assessed the effects of α-synuclein deletion on macroautophagy in mouse brains. We show that overexpression of wild-type α-synuclein in both mouse models of HD enhances the onset of tremors and has some influence on the rate of weight loss. On the other hand, α-synuclein deletion in both HD models increases autophagosome numbers and this is associated with a delayed onset of tremors and weight loss, two of the most prominent endophenotypes of the HD-like disease in mice. We have therefore established a functional link between these two aggregate-prone proteins in mammals and provide further support for the model that wild-type α-synuclein negatively regulates autophagy even at physiological levels.     

Juvenile Huntington's disease: does a dosage-effect pathogenic mechanism differ from the classical adult disease?

Huntington's disease (HD) is caused by a CAG repeat mutation translating as a polyglutamine (poly(Q)) expansion in the huntingtin protein, whose main pathogenic mechanism is a gain of toxic function. In the case of large expansions beyond 60 repeats onset may result in juvenile HD (JHD, onset before 20 years of age). However, the triplet number does not represent the only onset modifier even in case of large expansions, mechanisms other than the size of the mutation contribute to the phenotype. In this review we discuss the possibility that some of the pathogenic mechanisms contributing to age at onset and progression may differ in the early onset HD compared with the classical adult pathology.     

Cholesterol dysfunction in neurodegenerative diseases: Is Huntington's disease in the list?

Brain cholesterol is an essential component of cell membranes, and involved in a number of biological functions such as membrane trafficking, signal transduction, myelin formation and synaptogenesis. Given these widespread activities and the knowledge that all brain cholesterol derives from local synthesis, it is not surprising that dysfunctions in cholesterol synthesis, storage, transport and removal may lead to human brain diseases. Some of these diseases emerge as a consequence of genetic defects in the enzymes involved in cholesterol biosynthesis; in other cases, such as Alzheimer's disease, there is a link between cholesterol metabolism and the formation and deposition of amyloid-beta peptide. Emerging evidence indicates that changes in cholesterol synthesis may also occur in Huntington's disease, an inherited, autosomal dominant neurodegenerative disorder that primarily affects striatal neurons of the brain. We here provide an overview of the involvement of cholesterol in normal brain function and its impact on neurodegenerative diseases. In particular, we consider the available clinical, biological and molecular evidence indicating a potential dysregulation of cholesterol homeostasis in Huntington's disease.     

Huntington's disease: how does huntingtin, an anti-apoptotic protein, become toxic?

Huntington's disease belongs to a class of inherited neurological disorders that are caused by the presence of a polyglutamine expansion in apparently unrelated proteins. In Huntington's disease, expansion occurs in the huntingtin protein. Together with the characteristic formation of aggregates in the diseased state, several post-translational modifications affect huntingtin during the pathological process and lead to the dysfunction and eventual death of selective neurons in the brain of patients. These mechanisms are not completely described but could involve the gain of a new toxic function as well as the loss of the beneficial properties of huntingtin.     

Glutathione S-Transferase Ω 1 variation does not influence age at onset of Huntington's disease

Background

Huntington's disease (HD) is a fully penetrant, autosomal dominantly inherited disorder associated with abnormal expansions of a stretch of perfect CAG repeats in the 5' part of the IT15 gene. The number of repeat units is highly predictive for the age at onset (AO) of the disorder. But AO is only modestly correlated with repeat length when intermediate HD expansions are considered. Circumstantial evidence suggests that additional features of the HD course are based on genetic traits. Therefore, it may be possible to investigate the genetic background of HD, i.e. to map the loci underlying the development and progression of the disease. Recently an association of Glutathione S-Transferase Ω 1 (GSTO1) and possibly of GSTO2 with AO was demonstrated for, both, Alzheimer's (AD) and Parkinson's disease (PD).

Methods

We have genotyped the polymorphisms rs4925 GSTO1 and rs2297235 GSTO2 in 232 patients with HD and 228 controls.

Results

After genotyping GSTO1 and GSTO2 polymorphisms, firstly there was no statistically significant difference in AO for HD patients, as well as secondly for HD patients vs. controls concerning, both, genotype and allele frequencies, respectively.

Conclusion

The GSTO1 and GSTO2 genes flanked by the investigated polymorphisms are not comprised in a primary candidate region influencing AO in HD.     

Dramatic mutation instability in HD mouse striatum: does polyglutamine load contribute to cell-specific vulnerability in Huntington's disease?

An unstable CAG triplet repeat expansion encoding a polyglutamine stretch within the ubiquitously expressed protein huntingtin is responsible for causing Huntington's disease (HD). By quantifying the repeat sizes of individual mutant alleles in tissues derived from an accurate genetic mouse model of HD we show that the mutation becomes very unstable in striatal tissue. The expansion-biased changes increase with age, such that some striatal cells from old HD mice contain mutations that have tripled in size. If this pattern of repeat instability is recapitulated in human striatal tissue, the concomitant increased polyglutamine load may contribute to the patterns of selective neuronal cell death in HD. Our findings also suggest that trinucleotide repeat instability can occur by mechanisms that are not replication-based.     

Does mRNA translation starting from an alternative initiation site contribute to the pathology of Huntington's disease?

Huntington's disease is associated with an expanded and unstable trinucleotide repeat (CAG)(n). Various possibilities have been suggested to explain the significance of poly-(CAG) length in HD, including changes in the structure of the product (huntingtin) which result in the protein acquiring deleterious properties. We have looked at the nucleotide sequence coding for huntingtin and find that another possibility may exist for the correlation between the occurrence of HD and poly-CAG length. We have noted an alternative reading frame that includes the trinucleotide repeat, now read as (GCA)(n). Upon close examination of this alternative gene product, we observe features that suggest it can likewise have deleterious properties.     

α-Synuclein accumulates in huntingtin inclusions but forms independent filaments and its deficiency attenuates early phenotype in a mouse model of Huntington's disease

Huntington's disease (HD) is the most common of nine inherited neurological disorders caused by expanded polyglutamine (polyQ) sequences which confer propensity to self-aggregate and toxicity to their corresponding mutant proteins. It has been postulated that polyQ expression compromises the folding capacity of the cell which might affect other misfolding-prone proteins. α-Synuclein (α-syn) is a small neural-specific protein with propensity to self-aggregate that forms Parkinson's disease (PD) Lewy bodies. Point mutations in α-syn that favor self-aggregation or α-syn gene duplications lead to familial PD, thus indicating that increased α-syn aggregation or levels are sufficient to induce neurodegeneration. Since polyQ inclusions in HD and other polyQ disorders are immunopositive for α-syn, we speculated that α-syn might be recruited as an additional mediator of polyQ toxicity. Here, we confirm in HD postmortem brains and in the R6/1 mouse model of HD the accumulation of α-syn in polyQ inclusions. By isolating the characteristic filaments formed by aggregation-prone proteins, we found that N-terminal mutant huntingtin (N-mutHtt) and α-syn form independent filamentous microaggregates in R6/1 mouse brain as well as in the inducible HD94 mouse model and that N-mutHtt expression increases the load of α-syn filaments. Accordingly, α-syn knockout results in a diminished number of N-mutHtt inclusions in transfected neurons and also in vivo in the brain of HD mice. Finally, α-syn knockout attenuates body weight loss and early motor phenotype of HD mice. This study therefore demonstrates that α-syn is a modifier of polyQ toxicity in vivo and raises the possibility that potential PD-related therapies aimed to counteract α-syn toxicity might help to slow HD.     

Histamine intolerance: a metabolic disease?

Objective

To evaluate the evidence regarding the disease concept of histamine intolerance as a state of inadequate histamine inactivation.

Methods

Keyword-based systematic screening of the scientific literature and of public websites focusing on diagnostic and therapeutic procedures.

Results

Histamine intolerance is commonly diagnosed based solely on subjective reporting of symptoms instead of following systematic diagnostic procedures based on objective laboratory and physical parameters. The only effective long-term therapy is avoidance of histamine-containing food.

Conclusions

The concept of histamine intolerance as a metabolic disease is in need of more experimental and clinical evidence and affected patients will benefit from a clear, evidence-based diagnostic and therapeutic regime.

     

Micro-invasive vulvar Paget's disease and lymph node metastasis: a same disease?

Vulvar Paget's disease is sub-classified into three types based upon its origin. It might be a primary vulvar disease (type 1) or associated with a non-cutaneous adenocarcinoma-rectal, colonic, cervical (type 2) or linked with an urothelial neoplasia (type 3). Type 1lesions must be considered as potentially invasive. Their immunophenotype is CK7+/CK20-. Classically, in case of depth of invasion below 1mm, nodal metastases are exceptional. We report a case of type 1?Paget's disease in a postmenopausal woman with superficial invasion and multiple inguinal nodal metastases.     

Parkinson’s disease and Alzheimer’s disease: a Mendelian randomization study

Background

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the top two common neurodegenerative diseases in elderly. Recent studies found the α-synuclein have a key role in AD. Although many clinical and pathological features between AD and PD are shared, the genetic association between them remains unclear, especially whether α-synuclein in PD genetically alters AD risk.

Results

We did not obtain any significant result (OR?=?0.918, 95% CI: 0.782–1.076, P?=?0.291) in MR analysis between PD and AD risk. In MR between α-synuclein in PD with AD risk, we only extracted rs356182 as the IV through a strict screening process. The result indicated a significant association based on IVW method (OR?=?0.638, 95% CI: 0.485–0.838, P?=?1.20E-03). In order to examine the robustness of the IVW method, we used other three complementary analytical methods and also obtained consistent results.

Conclusion

The overall PD genetic risk factors did not predict AD risk, but the α-synuclein susceptibility genetic variants in PD reduce the AD risk. We believe that our findings may help to understand the association between them, which may be useful for future genetic studies for both diseases.