The efficacy of sacituzumab govitecan and trastuzumab deruxtecan on stable and active brain metastases in metastatic breast cancer patients-a multicenter real-world analysis

BACKGROUND

Fifteen to thirty percent of all patients with metastatic breast cancer (MBC) develop brain metastases (BCBMs). Recently, the antibody-drug conjugates (ADCs) sacituzumab govitecan (SG) and trastuzumab deruxtecan (T-DXd) have shown to be highly effective in the treatment of MBC. However, there are only limited data whether these macromolecules are also effective in patients with BCBMs. We therefore aimed to examine the efficacy of SG and T-DXd in patients with stable and active BCBMs in a multicenter real-world analysis.

PATIENTS AND METHODS

Female patients with stable or active BCBMs who were treated with either SG or T-DXd at three breast centers in Germany before 30 June 2023 were included. As per local clinical praxis, chemotherapy efficacy was evaluated by whole-body computed tomography and cranial magnetic resonance imaging at baseline and at least every 3 months according to local standards. Growth dynamics of BCBMs were assessed by board-certified neuroradiologists.

RESULTS

Of 26 patients, with a median of 2.5 prior therapy lines in the metastatic setting (range 2-15), 12 (43%) and 16 (57%) patients received SG and T-DXd, respectively. Out of the 12 patients who received SG, 2 (17%) were subsequently treated with T-DXd. Five out of 12 (42%) and 5 out of 16 (31%) patients treated with SG and T-DXd, respectively, had active BCBMs at treatment initiation. The intracranial disease control rate was 42% [95% confidence interval (CI) 13% to 71%] for patients treated with SG and 88% (95% CI 72% to 100%) for patients treated with T-DXd. After a median follow-up of 12.7 months, median intracranial progression-free survival was 2.7 months (95% CI 1.6-10.5 months) for SG and 11.2 months (95% CI 7.5-23.7 months) for T-DXd.

CONCLUSIONS

SG and T-DXd showed promising clinical activity in both stable and active BCBMs. Further prospective clinical studies designed to investigate the efficacy of modern ADCs on active and stable BCBMs are urgently needed.

Soluble NKG2DLs Are Elevated in Breast Cancer Patients and Associate with Disease Outcome

Ligands of the natural killer group 2D (NKG2DL) family are expressed on malignant cells and are usually absent from healthy tissues. Recognition of NKG2DLs such as MICA/B and ULBP1-3 by the activating immunoreceptor NKG2D, expressed by NK and cytotoxic T cells, stimulates anti-tumor immunity in breast cancer. Upregulation of membrane-bound NKG2DLs in breast cancer has been demonstrated by immunohistochemistry. Tumor cells release NKG2DLs via proteolytic cleavage as soluble (s)NKG2DLs, which allows for effective immune escape and is associated with poor prognosis. In this study, we collected serum from 140 breast cancer (BC) and 20 ductal carcinoma in situ (DCIS) patients at the time of initial diagnosis and 20 healthy volunteers (HVs). Serum levels of sNKG2DLs were quantified through the use of ELISA and correlated with clinical data. The analyzed sNKG2DLs were low to absent in HVs and significantly higher in BC patients. For some of the ligands analyzed, higher sNKG2DLs serum levels were associated with the classification of malignant tumor (TNM) stage and grading. Low sMICA serum levels were associated with significantly longer progression-free (PFS) and overall survival (OS). In conclusion, we provide the first insights into sNKG2DLs in BC patients and suggest their potential role in tumor immune escape in breast cancer. Furthermore, our observations suggest that serum sMICA levels may serve as a prognostic parameter in the patients analyzed in this study.

The Clinical Relevance of the NATALEE Study: Application of the NATALEE Criteria to a Real-World Cohort from Two Large German Breast Cancer Centers

The NATALEE study showed a significant benefit in invasive disease-free survival (iDFS) for patients with HR+/HER2- early breast cancer (eBC) at intermediate and high risk of recurrence who were treated with the CDK4/6 inhibitor Ribociclib in combination with endocrine therapy (ET). This retrospective study aims to apply the NATALEE inclusion criteria to a representative real-world cohort to estimate the proportion of HR+/HER2- breast cancer patients eligible for adjuvant Ribociclib therapy. Patients who underwent full surgical treatment for eBC between January 2018 and December 2020 at two large German university breast cancer centers (University of Ulm, University of Tuebingen) were included. Descriptive statistics were used to characterize the patient population eligible for Ribociclib treatment based on the NATALEE study's inclusion criteria. Out of 2384 enrolled patients, 1738 had HR+/HER2- eBC, of whom 43% (747/1738) met the NATALEE inclusion criteria. Of note, these patients were older, received less chemotherapy and presented with less advanced tumor stages compared to the NATALEE study cohort. Additionally, compared to the NATALEE study cohort, fewer patients had lymph node involvement (72.4% vs. 88.7%). Our analysis suggests that approximately 43% of all HR+/HER2- breast cancer patients will qualify for Ribociclib treatment. Given the numerous treatment options for patients with HR+/HER2- eBC, as well as the differences between the NATALEE cohort and patients in the real-world clinical setting, future analyses will be needed to determine which patients would benefit most from adjuvant CDK4/6 inhibitor treatment.

Long-Term Follow-Up of COVID-19 Convalescents-Immune Response Associated with Reinfection Rate and Symptoms

SARS-CoV-2 has spread worldwide, causing millions of deaths and leaving a significant proportion of people with long-term sequelae of COVID-19 ("post-COVID syndrome"). Whereas the precise mechanism of post-COVID syndrome is still unknown, the immune response after the first infection may play a role. Here, we performed a long-term follow-up analysis of 110 COVID-19 convalescents, analyzing the first SARS-CoV-2-directed immune response, vaccination status, long-term symptoms (approximately 2.5 years after first infection), and reinfections. A total of 96% of convalescents were vaccinated at least once against SARS-CoV-2 after their first infection. A reinfection rate of 47% was observed, and lower levels of anti-spike IgG antibodies after the first infection were shown to associate with reinfection. While T-cell responses could not be clearly associated with persistent postinfectious symptoms, convalescents with long-term symptoms showed elevated SARS-CoV-2-specific antibody levels at the first infection. Evaluating the immune response after the first infection might be a useful tool for identifying individuals with increased risk for re-infections and long-term symptoms.

Targeting NKG2DL with Bispecific NKG2D-CD16 and NKG2D-CD3 Fusion Proteins on Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a particularly aggressive subtype of breast cancer with a poor response rate to conventional systemic treatment and high relapse rates. Members of the natural killer group 2D ligand (NKG2DL) family are expressed on cancer cells but are typically absent from healthy tissues; thus, they are promising tumor antigens for novel immunotherapeutic approaches. We developed bispecific fusion proteins (BFPs) consisting of the NKG2D receptor domain targeting multiple NKG2DLs, fused to either anti-CD3 (NKG2D-CD3) or anti-CD16 (NKG2D-CD16) Fab fragments. First, we characterized the expression of the NKG2DLs (MICA, MICB, ULBP1-4) on TNBC cell lines and observed the highest surface expression for MICA and ULBP2. Targeting TNBC cells with NKG2D-CD3/CD16 efficiently activated both NK and T cells, leading to their degranulation and cytokine release and lysis of TNBC cells. Furthermore, PBMCs from TNBC patients currently undergoing chemotherapy showed significantly higher NK and T cell activation and tumor cell lysis when stimulated with NKG2D-CD3/CD16. In conclusions, BFPs activate and direct the NK and T cells of healthy and TNBC patients against TNBC cells, leading to efficient eradication of tumor cells. Therefore, NKG2D-based NK and T cell engagers could be a valuable addition to the treatment options for TNBC patients.

Which Patients Do We Need to Test for BRCA1/2 Mutation? Feasibility of Adjuvant Olaparib Treatment in Early Breast Cancer-Real-World Data from Two Large German Breast Centers

BACKGROUND

Approximately 6% of women with breast cancer carry pathogenic germline variants in predisposition genes such as BRCA1 and BRCA2. Depending on personal and family cancer history, it is therefore recommended to test for hereditary breast cancer. Moreover, as shown by the phase III OlympiA trial, olaparib significantly improves overall survival in patients with HER2 negative (HER2-) early breast cancer who (1) carry a BRCA1 or BRCA2 germline mutation (gBRCA1/2-positive), (2) have received (neo)adjuvant chemotherapy and (3) are at high clinical risk. The objective of the current analysis was to determine the number of patients with early HER2- breast cancer who are at high clinical risk, according to the inclusion criteria of OlympiA, and to estimate how many of these patients would meet the criteria for hereditary cancer testing in a real-world analysis.

METHODS

All patients included in this retrospective analysis were treated for early breast cancer (eBC) at the Department of Gynecology and Obstetrics, Ulm University Hospital, Germany, and the Department of Women's Health at Tuebingen University Hospital, Germany, between January 2018 and December 2020. Patients were identified as high risk, in line with the clinicopathological determiners used in the OlympiA trial. The criteria of the German Consortium for Hereditary Breast and Ovarian Cancer were used to identify patients who qualify for hereditary cancer testing.

RESULTS

Of 2384 eligible patients, 1738 patients (72.9%) showed a hormone receptor positive (HR+)/HER2- tumor biology, 345 patients (14.5%) displayed HER2+ breast cancer and 301 patients (12.6%) suffered from HR-/HER2- breast cancer (TNBC). Of 2039 HER2- breast cancer patients, 271 patients (13.3%) were at high clinical risk. This cohort encompassed 130 of the 1738 patients with HR+/HER2- breast cancer (7.5%) and 141 of 301 patients with TNBC (46.8%). A total of 121 of 271 patients (44.6%) with high clinical risk met the criteria for hereditary cancer testing (34 of 130 (26.2%) HR+/HER2- patients and 87 of 141 (61.7%) patients with TNBC).

CONCLUSION

Approximately one in ten patients with HR+/HER2-, and half of the patients with TNBC, meet the high-risk criteria according to OlympiA. Half of these patients do not meet the criteria for hereditary cancer testing and should therefore be tested for the presence of gBRCA1/2 mutations, irrespective of their own or family cancer history. The overall number of patients with early breast cancer benefiting from olaparib needs to be investigated in future studies.

The impact of rehabilitation sport on breast cancer-related lymphoedema and quality of life

PURPOSE

Surgery and radiotherapy as part of breast cancer treatment can lead to lymphoedema of the upper extremities (breast cancer-related lymphoedema = BCRL) and reduce the quality of life (health-related quality of life = HRQoL). The aim of the present study was to investigate the influence of paddling in a dragon boat (PP) on HRQoL and BCRL in breast cancer survivors (BCS).

METHODS

Between April and October 2017, a prospective case-control study evaluated the effects of PP compared to a control group. In the paddle group (n = 28), weekly arm circumference measurements were taken at four defined anatomic areas of the arm before and after training; in the control group (n = 70), the measurements were taken once a month. At the beginning and end of the study, questionnaires from both groups (SF 36, EORTC QLQ C30) were evaluated to understand the differences in HRQoL.

RESULTS

The paddle group started with a higher HRQoL compared to the control group. Most interesting, whether the affected or unaffected arm, whether before or after training-the arm circumference decreased over time in the paddling group. A pre-existing lymphoedema was not negatively influenced by paddling. In the paddle group, the physical health was constant over the season, while the physical health of the control group decreased significantly over time.

CONCLUSION

PP in a dragon boat does not lead to the development or worsening of pre-existing lymphoedema due to breast cancer therapy, and seems to have a positive effect on the quality of life.

Evaluation of sonographic detectability of different markers within an in vitro simulation model of the axilla

PURPOSE

Clip-marking of axillary lymph nodes with initial biopsy-confirmed metastasis is required for targeted axillary dissection (TAD), which includes sentinel lymph node dissection (SLND) and selective localization and removal of the clipped targeted lymph node. There have been several studies which examined the feasibility of TAD in routine clinical use. In this context, the optimal clip visualisation was noted as one of the crucial limiting factors. We, therefore, evaluated the sonographic detectability of 10 different commercially available markers within an in vitro model simulating the anatomical composition of the axilla.

METHODS

In this standardised model consisting of porcine fat with 30 mm thickness, the visibility of a total of ten markers was analysed in all 3 planes (parallel, diagonal, orthograde) with wire guidance and then classified into either "visibility good", "visibility moderate" or "visibility poor" with regard to the alignment of the transducer. Additionally, "real-life conditions" were simulated, in which the markers were searched without any wires guidance.

RESULTS

It was observed that, while not all markers are detectable in fatty tissue, markers with spherical shape (non-embedded Inconel or Nitinol) or rectangular-shaped Titanium markers with embedded material have a clear advantage. 3D-shaped markers can always be detected in all three axes, which is of particular importance in the axilla with its pyramid shape and fatty tissue.

CONCLUSION

The shape and the embedding of the material play a crucial role for visibility and efficacy of the marker, as reliable marking of suspicious and pathological axillary lymph nodes is essential for TAD.

Large-scale discovery of novel genetic causes of developmental disorders

Despite three decades of successful, predominantly phenotype-driven discovery of the genetic causes of monogenic disorders, up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis. Particularly challenging are those disorders rare enough to have eluded recognition as a discrete clinical entity, those with highly variable clinical manifestations, and those that are difficult to distinguish from other, very similar, disorders. Here we demonstrate the power of using an unbiased genotype-driven approach to identify subsets of patients with similar disorders. By studying 1,133 children with severe, undiagnosed developmental disorders, and their parents, using a combination of exome sequencing and array-based detection of chromosomal rearrangements, we discovered 12 novel genes associated with developmental disorders. These newly implicated genes increase by 10% (from 28% to 31%) the proportion of children that could be diagnosed. Clustering of missense mutations in six of these newly implicated genes suggests that normal development is being perturbed by an activating or dominant-negative mechanism. Our findings demonstrate the value of adopting a comprehensive strategy, both genome-wide and nationwide, to elucidate the underlying causes of rare genetic disorders.

The clinical, histochemical, and molecular spectrum of PEO1 (Twinkle)-linked adPEO

BACKGROUND

Mutations in the Twinkle (PEO1) gene are a recognized cause of autosomal dominant progressive external ophthalmoplegia (adPEO), resulting in the accumulation of multiple mitochondrial DNA (mtDNA) deletions and cytochrome c oxidase (COX)-deficient fibers in skeletal muscle secondary to a disorder of mtDNA maintenance. Patients typically present with isolated extraocular muscle involvement, with little apparent evidence of the clinical heterogeneity documented in other mtDNA maintenance disorders, in particular POLG-related disease.

METHODS

We reviewed the clinical, histochemical, and molecular genetics analysis of 33 unreported patients from 26 families together with all previous cases described in the literature to define the clinical phenotype associated with PEO1 mutations.

RESULTS

Ptosis and ophthalmoparesis were almost universal clinical features among this cohort, with 52% (17/33) reporting fatigue and 33% (11/33) having mild proximal myopathy. Features consistent with CNS involvement were rarely described; however, in 24% (8/33) of the patients, cardiac abnormalities were reported. Mitochondrial histochemical changes observed in muscle showed remarkable variability, as did the secondary mtDNA deletions, which in some patients were only detected by PCR-based assays and not Southern blotting. Moreover, we report 7 novel PEO1 variants.

CONCLUSIONS

Our data suggest a shared clinical phenotype with variable mild multiorgan involvement, and that the contribution of PEO1 mutations as a cause of adPEO may well be underestimated. Direct sequencing of the PEO1 gene should be considered in adPEO patients prior to muscle biopsy.

Parafibromin mutations in hereditary hyperparathyroidism syndromes and parathyroid tumours

OBJECTIVE

To investigate two patients with the hyperparathyroidism-jaw tumour (HPT-JT) syndrome and three patients with familial isolated hyperparathyroidism (FIHP), together with 31 parathyroid tumours (2 HPT-JT, 2 FIHP and 27 sporadic) for HRPT2 mutations. The HPT-JT syndrome and FIHP are autosomal dominant disorders that may be caused by abnormalities of the HRPT2 gene, located on chromosome 1q31.2. HRPT2 encodes a 531 amino acid protein, parafibromin, which interacts with human homologues of the yeast Paf1 complex.

DESIGN

Leukocyte and tumor DNA was used with HRPT2-specific primers for polymerase chain reaction amplification of the 17 exons and their splice junctions, and the DNA sequences of the polymerase chain reaction products determined.

RESULTS

Three heterozygous germline HRPT2 mutations, two in HPT-JT and one in FIHP patients, were identified. These consisted of one 1-bp duplication (745dup1bp), 1 nonsense (Arg234Stop) and 1 missense (Asp379Asn) mutation. One parathyroid tumour from an FIHP patient was demonstrated to harbour a germline deletion of 1 bp together with a somatic missense (Leu95Pro) mutation, consistent with a 'two-hit' model for hereditary cancer. The 27 sporadic benign parathyroid tumours did not harbour any HRPT2 somatic mutations. Six HRPT2 polymorphisms with allele frequencies ranging from 2% to 15% were detected.

CONCLUSIONS

Our results have identified three novel HRPT2 mutations (two germline and one somatic). The Asp379Asn mutation is likely to disrupt interaction with the human homologue of the yeast Paf1 complex, and the demonstration of combined germline and somatic HRPT2 mutations in a parathyroid tumour provide further evidence for the tumour suppressor role of the HRPT2 gene.

Service provision of complex mutation analysis: a technical and economic appraisal using dystrophin point mutation analysis as an example

Duchenne muscular dystrophy (DMD) results from mutations in the dystrophin gene. One-third of cases arise from point mutations, which are heterogeneous and difficult to detect. The aims of this study of dystrophin point mutation analysis were to assess its technical feasibility in a routine diagnostic laboratory, and to estimate its costs and clinical benefits. The methods used were a laboratory based study using reverse transcription-polymerase chain reaction (RT-PCR) and a protein truncation test, and a mathematical model to estimate costs and clinical benefits. None of the cases analyzed had an identifiable dystrophin deletion or duplication. They were 12 males affected with DMD and two obligate female carriers; two female carriers of known dystrophin point mutations were also analyzed. Point mutations were detected in six out of 12 males, but in none of the female carriers. Assuming a sensitivity of 50% the model predicts significant clinical benefits of point mutation analysis over linkage analysis, including a reduction in the number of prenatal diagnoses (by 0.77 per family), terminations of pregnancy (by 0.18 per family), and terminations of unaffected fetuses (by 0.16 per family). The mean cost of point mutation analysis to prevent the termination of an unaffected fetus is 6220 US dollars.

Normal in vivo skeletal muscle oxidative metabolism in sporadic inclusion body myositis assessed by 31P-magnetic resonance spectroscopy

Sporadic inclusion body myositis (s-IBM) is a chronic inflammatory myopathy of unknown pathogenesis. The common findings of ragged red fibres, cytochrome c oxidase-negative fibres and multiple mitochondrial DNA deletions in the muscle of patients with s-IBM have suggested that a deficit of energy metabolism may be of pathogenic relevance. To test this hypothesis we used 31P magnetic resonance spectroscopy to assess in vivo skeletal muscle mitochondrial function in the calf muscles of 12 patients with definite s-IBM. Eleven patients showed multiple mitochondrial DNA deletions in skeletal muscle and 67% showed ragged red fibres and/or cytochrome c oxidase-negative fibres. T1-weighted MR images showed increased signal intensity in the calf muscle of all patients except one. The involvement of calf muscle was confirmed by 31P magnetic resonance spectroscopy of resting muscle, which disclosed abnormalities in metabolite ratios in all patients. However, muscle oxidative metabolism assessed during recovery from exercise was normal in patients with s-IBM, as maximum rates of mitochondrial ATP production and post-exercise ADP recovery rates were within the normal range in all cases. We conclude that muscle mitochondrial abnormalities are a secondary process and unlikely to play a significant role in the pathogenesis of s-IBM.

Pulsed field gel electrophoresis for detection of gene rearrangements in duchenne muscular dystrophy

In diseases with a high new mutation rate, such as Duchenne and Becker muscular dystrophy (DMD, BMD), linkage analysis often produces highly unsatisfactory results for carrier diagnosis compared to methods that rely on the direct detection of the mutation. The size of the dystrophin gene and the nature of mutations at this locus that give rise to DMD/BMD make pulsed field gel electrophoresis (PFGE) an appropriate and powerful technique for detection of mutations and hence accurate carrier diagnosis in these diseases.

Molecular characterization of further dystrophin gene microsatellites

Microsatellites of the dystrophin gene have been used extensively in the genetic analysis of Duchenne and Becker muscular dystrophy families. The microsatellites that have been reported to date are clustered within disparate regions of the dystrophin gene, specifically at the 5'-end and in the central rod-domain. YACs encompassing the gene were screened for further microsatellites to improve the density of available genetic markers. Four microsatellites were localized to defined regions of the dystrophin gene by the analysis of patient DNA samples, somatic cell hybrids and YACs. In addition, varying combinations of microsatellite loci were amplified in multiplex PCRs, which complement those loci that have been studied to date.

Leukotriene receptors on human pulmonary vascular endothelium

1. Cysteinyl-leukotrienes cause contractions and/or relaxations of human isolated pulmonary vascular preparations. Although, the localization and nature of the receptors through which these effects are mediated have not been fully characterized, some effects are indirect and not mediated via the well-described LT1 receptor. 2. In human pulmonary veins (HPV) with an intact endothelium, leukotriene D4 (LTD4) induced contraction above basal tone. This response was observed at lower concentrations of LTD4 in the presence of nitric oxide synthase inhibitor N omega-nitro-L-arginine (L-NOARG). Contractions (in the absence and presence of L-NOARG) were partially blocked by the LT1 antagonists (MK 571 and ICI 198615). 3. LTD4 relaxed HPV previously contracted with noradrenaline. This relaxation was potentiated by LT1 antagonists, but was abolished by removal of the endothelium. LTD4 also relaxed human pulmonary arteries (HPA) precontracted with noradrenaline but this effect was not modified by LT1 antagonists. 4. The results suggest that contraction of endothelium-intact HPV by LTD4 is partially mediated via LT1 receptors. Further, in endothelium-intact HPV, this contraction was opposed by a relaxation induced by LTD4, dependent on the release of nitric oxide, which was mediated, at least in part, via a non-LT1 receptor. In addition, LTD4 relaxation on contracted HPA was not mediated by LT1 receptors. 5. The mechanical effects of LTD4 on human pulmonary vasculature are complex and involve both direct and indirect mechanisms mediated via at least two types of cysteinyl-leukotriene receptors.

Identification of six mutations (R31L, 441delA, 681delC, 1461ins4, W1089R, E1104X) in the cystic fibrosis transmembrane conductance regulator (CFTR) gene

Six new mutations have been identified in the CFTR gene. These mutations, representing three different categories--missense (R31L, W1098R), nonsense (E1104X), and frameshift (441delA, 681delC, 1461ins4)--are located in exons 2, 4, 5, 9, and 17b of the gene and presumed to cause cystic fibrosis (CF) in patients. All these mutations are probably rare in the population, as no additional examples were found for any of them in a cohort of 545 CF patients. Our study also revealed a benign sequence variation (3499 + 45T-->C) in intron 17b.

Cystic fibrosis mutation analysis: report from 22 U.K. regional genetics laboratories

We have collated the results of cystic fibrosis (CF) mutation analysis conducted in 22 laboratories in the United Kingdom. A total of 9,807 CF chromosomes have been analysed, demonstrating 56 different mutations so far observed and accounting for 86% of CF genes in the native Caucasian population of the United Kingdom. delta F508 is the most common at 75.3% of CF mutations (range 56.5-83.7%), followed by G551D (3.08%; range 0.71-7.60%), G542X (1.68%; range 0.85-3.66%), 621 + 1 (G > T) (0.93%; range 0.41-3.16%), 1717-1(G > A) (0.57%; range 0.17-1.14%), 1898 + 1)(G > A) (0.46%), R117H (0.46%), N1303K (0.46%), and R553X (0.46%). The data show a clear geographical variation in the distribution of some of the mutations, most notably a marked regional variation in the distribution of 621 + 1 (G > T) and 1989 + 1(G > A), which are both apparently more frequent in Wales. R560T and R117H appear to be more frequent in Ireland and Scotland, and G551D more frequent in Scotland. In summary, these data illustrate that the mutations present within a particular population need to be defined in order to provide meaningful carrier screening and testing for rare mutations in affected individuals. Furthermore, it is apparent that the ethnic origin of a patient, even within a small country such as the United Kingdom, should be taken into account.

Identification of rare and novel mutations in the CFTR genes of CF patients in southern England

Cystic fibrosis patients referred to two genetics centres in southern England and not found to carry common CF-associated mutations in one or both of their CFTR genes have been subjected to an extensive mutation search. The whole of the coding region of the CFTR gene, all intron-exon boundaries and 5' and 3' untranslated regions have been examined by a combination of single stranded conformational polymorphism analysis and chemical mismatch detection; 48 chromosomes with rare mutations have been identified, including 7 novel mutations, 182delT in exon 1, G27X in exon 2, Q151X in exon 4, Q220X in exon 6a, Q525X in exon 10, 3041delG in exon 16, and 4271delC in exon 23.

A clinico-genetic study of psychiatric disorder in Huntington's chorea

The introduction in 1985 of a genetic linkage test programme to identify asymptomatic heterozygotes among subjects at 50% initial risk for Huntington's chorea required a review of all cases of Huntington's chorea and their families referred to the Department of Medical Genetics of the Oxford Regional Health Area (population 2.5 million). From a representative sample of these subjects, psychiatric data were collected to estimate the frequency and time of onset of functional psychiatric illness and behaviour disorder. The rationale and method of the linkage test is described. The frequency of functional psychiatric disorder found was compared with that reported for the general population and for Alzheimer's disease. The role in relation to the aetiology of functional psychiatric disorder (1) of the Huntington's chorea gene and (2) of the family disturbance produced, was investigated by comparison between the frequency of functional psychiatric disorder in populations containing different proportions of heterozygotes as shown by (a) the manifestation of Huntington's chorea, and (b) the result of the genetic linkage analysis. In order to investigate the influence of the onset of Huntington's chorea on the production of functional psychiatric disorder the time of onset of the various functional psychiatric disorders was compared between asymptomatic subjects at 50% risk for Huntington's chorea and their cohabiting spouses who were assumed to be at zero risk and who shared their environment. It is concluded that possessing the Huntington's chorea gene: (1) has no influence on the production of functional psychiatric disorder in asymptomatic subjects at risk for Huntington's chorea; and (2) increases the tendency to major depressive disorder in subjects already affected with physical signs of Huntington's chorea.