Correlates of Perceived Harmfulness of Regular Cannabis Use among Canadian University Students Before and After Legalization

Objective

Among a prospective sample of Canadian university students, this study aimed to: 1) document changes in cannabis use and perceived harmfulness of use before and after the legalization of recreational cannabis; 2) examine correlates of perceived harmfulness; and 3) explore changes in perceived harmfulness as a function of cannabis use patterns.

Method

A random sample of 871 students at one western Canadian university were assessed pre- and post-legalization of recreational cannabis. Descriptive and inferential statistics were used to explore changes in cannabis use and perceived harmfulness. A random effects model was developed to assess whether cannabis legalization was associated with perceptions of harmfulness of regular cannabis use.

Results

Twenty-six percent of the sample used cannabis during the past three months at both timepoints. The majority of the sample perceived regular cannabis use as a high-risk behaviour at each timepoint (57.3% and 60.9%, respectively). Results from the random effects model showed that after controlling for covariates, cannabis legalization was not associated with changes in perceived harmfulness. Perceptions of harm remained relatively stable regardless of cannabis use pattern. Respondents who endorsed cannabis use at both timepoints reported a significant increase in their frequency of cannabis use post-legalization.

Conclusions

Legalization of cannabis for recreational use was not associated with substantive changes in perceptions of harm among post-secondary students, yet it might lead to increases in cannabis use among those who already use the substance. Ongoing monitoring of policies is needed, as are targeted public health initiatives to identify post-secondary students who are at risk for cannabis-related consequences.

Piloting virtual mentorship: Evaluating acceptability and influence on wellness and professional identity in medical oncology (MO)

11022

Background: Despite extensive literature on the value of mentorship in academic medicine, little evidence exists to inform mentorship practices in MO. In 2021, the Canadian Association of Medical Oncologists (CAMO) piloted a national, 6-month virtual mentorship program consisting of 2 group mentoring events and additional 1-on-1 mentoring activities, to better support the needs of MO trainees. Feedback was obtained from participants to gain insight into how virtual mentorship might impact physician wellness and formation of professional identity, and to inform future iterations of CAMO’s virtual mentorship strategy. Methods: All Canadian MO residents/fellows were invited to participate in the program. Electronic surveys were completed by participants at baseline, after each group event, and at program completion. Surveys evaluated the program content and format, and used validated questionnaires for evaluating physician wellness/burnout (Stanford Professional Fulfillment Index [SPFI]), and professional identity (Macleod Clark Professional Identity Scale [MCPIS]). Cohort characteristics and survey responses were summarized using descriptive statistics. Procedures for survey data collection and analysis were ethics approved. Results: At baseline, respondents (n = 38) were predominantly female (63%), and < 35 years (76%). 50% were married. On average, 78% of respondents ranked the virtual group mentoring events as meeting expectations. Program strengths identified by participants included meeting mentors outside of their own centre, meeting other trainees from across the country, and learning more about work-life balance/physician wellness. The main critique was insufficient time for interaction. Of the 34 MCPIS respondents, 94% were pleased to belong to the profession of MO, 91% identified positively with members of their profession and 77% felt like a member of the profession themselves. The average score on the SPFI scale was 2.73±0.71 (n = 34). Although 85% of respondents found their work meaningful, 71% satisfying, and 50% felt they were contributing professionally in valued ways, only 38% met criteria for professional fulfilment (score ≥3.00). 27% met criteria for burnout (score ≥1.33), 15% found their work physically exhausting and 9% found their work emotionally exhausting. Conclusions: CAMO’s pilot virtual mentorship program highlights that technology can be successfully leveraged to facilitate mentoring. The majority of MO trainees identified positively with their profession, yet only 38% reached the threshold for professional fulfillment and nearly a third met criteria for burnout. Longitudinal follow-up among mentored trainees is needed to provide insight into whether mentorship may influence physician wellness and professional identity over time.

“I die silently inside”. Qualitative findings from a Study of People living with HIV who Migrate to and Settle in Canada

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This study presents compelling accounts of African, Caribbean, and black (ACB) 2 immigrants who feel excluded, isolated, and distanced by others because of their positive 3 HIV status. 4.

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Among ACB immigration applicants living with HIV in Canada, a positive HIV status 5 had significant consequences on a person's ability to access health and social care, stable 6 housing, meaningful employment, as well as movement within society. 7.

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It is important to understand the experiences of racialized immigration applicants and 8 HIV screening processes during immigration from an intersectionality lens. 9.

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Health and social care providers of ACB immigrants living with HIV must consider the 10 interaction of race, legal status, institutional laws and structures, gender, culture, trauma, 11 and intergenerational contexts in providing adequate and appropriate health and social 12 care to this population.

We report on qualitative findings from a mixed methods study, examining enacted and internalized stigma during mandatory HIV screening among immigration applicants living with HIV in Canada. Qualitative findings show alignment with characteristics of internalized HIV stigma. We conducted 34 semi-structured interviews, and analyzed the data through thematic analysis, using Intersectionality and the Internalized HIV Stigma Scale as our theoretical and analytical frameworks. Participants described experiences of enacted and internalized HIV stigma in ways that were consistent with the four main domains of stereotypes, disclosure concerns, social relationships, and self-acceptance, but also extended the description of HIV stigma beyond these domains. Experiences of internalized HIV stigma and enacted stigma during the Canadian Immigration Medical Examination could potentially influence individuals’ long-term engagement in the HIV care cascade during the process of migration to, and settlement in, Canada. We present recommendations for the broader migrant health research agenda, health and social care providers, and public health policies.

Assessment Of Tumour Infiltrating Lymphocytes And Pd-l1 Expression In Adenoid Cystic Carcinoma Of The Salivary Gland

PURPOSE

Early phase clinical studies are ongoing to evaluate the role of immune checkpoint inhibitors in adenoid cystic carcinoma (ACC) despite a paucity of information on the immune microenvironment. This study aims to better characterize the immune microenvironment of ACC tumours and evaluate survival outcomes based on tumour infiltrating lymphocyte (TIL) and programmed death-ligand 1 (PD-L1) expression.

METHODS

Patient characteristics, treatment and outcome data were collected for 24 ACC patients. The CD8+(cluster of differentiation 8) TIL and PD-L1 expression were quantified by immunohistochemistry. Marker expression and survival outcomes were evaluated by Kaplan-Meier analysis.

RESULTS

All cases were negative for PD-L1 expression; four cases had focal high, eight cases had focal moderate and 12 cases had low TIL expression. Based on TIL expression, there was no difference in disease-free or overall survival.

CONCLUSION

Adenoid cystic carcinoma tumours were found to be associated with a poor immunogenic microenvironment, with absent PD-L1 expression and low CD8+ TILs. There was no association between TIL expression and survival. These data suggest that PD-L1 and TIL expression are unlikely to be useful as predictive biomarkers for response to immunotherapy.

Mandatory HIV screening, migration and HIV stigma in Canada: exploring the experiences of sub-Saharan African immigrants living with HIV in western Canada

INTRODUCTION

In this mixed-methods pilot study, we examined the intersections of the current Canadian immigration policy, mandatory HIV screening during the Immigration Medical Exam (IME) and enacted and internalized stigma for HIV-positive immigrants from sub-Saharan Africa (SSA) in a western Canadian province. We focus on qualitative findings from this study.

METHODS

Using the Internalized HIV Stigma Scale (IHSS), we collected data from eight immigrants from SSA living with HIV in a western Canadian province. We then conducted semistructured interviews with seven of the eight participants. Due to the small sample size, survey data were summarized using descriptive analysis. Qualitative data were analyzed through constant comparative analysis.

RESULTS

The following key themes emerged from analysis of qualitative data: experiences of HIV-related emotional distress during the IME; varied experiences of HIV testing during the IME; and inconsistent patterns of linkage to medical care, psychosocial supports and engagement in the HIV care cascade.

CONCLUSION

Findings from this pilot study cannot be generalized to the broader population of immigrants living with HIV in Canada. However, we found that the experiences of internalized HIV stigma and enacted stigma during the IME potentially influence the long-term engagement in the HIV care cascade during the process of migration and settlement in Canada. Further study in this population is recommended to examine the intersections of current mandatory HIV screening process during the Canadian immigration process, migration, settlement, culture, stigma and engagement in the HIV care cascade.

Fear of cancer recurrence among survivors of childhood cancer

OBJECTIVES

Fear of cancer recurrence (FCR) has not been widely explored in survivors of childhood cancer. Yet, childhood survivors are at risk of experiencing late effects and may be especially vulnerable. The aims of the current study were to conduct a retrospective chart review to determine the prevalence and persistence of FCR among survivors of childhood cancer and to examine factors that may be related to FCR.

METHODS

Survivors of childhood cancer (n = 228, mean attained age = 14.5 years [range = 4.7-21 years]; mean diagnosis age = 4.4 years [range = 0-16.5 years]; mean time off treatment = 8.7 years [range = 2.8-19.3 years]) seen in a Long-Term Survivor Clinic (LTSC) completed questionnaires at each clinic visit detailing their current health. FCR was measured with a single item. Data from questionnaires from 2011 to 2018 were analyzed retrospectively. Descriptive statistics and a random effects model were used to address study aims.

RESULTS

FCR was reported in 43% (n = 98) of survivors at least once across all clinic visits. Among survivors reporting FCR at least once, 66% were diagnosed with cancer under the age of 5, and 64% were 13 years or older at their most recent follow-up. Twenty-one percent of survivors (n = 48/224) reported FCR during at least 50% of their visits. Survivors with a higher number of depressive symptoms were more likely to report FCR (OR = 1.66, P = .03).

CONCLUSIONS

FCR is prevalent among survivors of childhood cancer and is related to other health concerns. Research is needed to understand who is at risk and how to.

Correlates of lifetime cannabis use and cannabis use severity in a Canadian university sample

This study aimed to broaden previous investigations of correlates of lifetime cannabis use and problematic cannabis use among post-secondary students by examining the novel and contemporary issues of medicinal use and deep inhalation practices. The sample included 2212 undergraduate and graduate post-secondary students from Alberta, Canada, who completed the University of Calgary's Campus Experience with Cannabis Survey (average age 23.2, SD = 5.2). Nine variables were entered into the binary logistic regression to examine their differentiation of lifetime users from non-users. A multiple regression model was completed with past six-month users (n = 697), where the continuous dependent variable was cannabis use severity as measured by total scores on the Cannabis Use Disorder Identification Test-Revised. Twenty independent variables were entered simultaneously. Varsity athlete status, family mental illness, severity of alcohol use, greater support for legalization and lower perceived risk associated with regular cannabis use, differentiated lifetime users from non-users. Higher rates of religiosity and living with parents or relatives were associated with lower-lifetime rates. Male gender, earlier age of first cannabis use, cannabis use motives (including coping, enhancement and expansion), past six-month medicinal use and increased frequency of deep inhalation during consumption, were found to be significant correlates of severity. Different factors seem to predict lifetime cannabis use versus severity, and these differences may help inform the development and delivery of prevention efforts. Given that medicinal use and male gender were the largest correlates of severity, populations representing these groups may benefit most from targeted education and prevention.

Real-world use of trifluridine/tipiracil for patients with metastatic colorectal cancer in Canada

Background

Outcomes for patients with metastatic colorectal cancer (mcrc) are improving with the introduction of new treatments. Treatment for patients who are still fit after failure of all available therapies represents a significant unmet need. In the present study, we analyzed real-world treatment patterns for patients enrolled in Health Canada's trifluridine/tipiracil (ftd/tpi) Special Access Program (sap) and Taiho Pharma Canada's Patient Support Program (psp).

Methods

Demographic information and clinical treatment data were collected from adults with mcrc who were previously treated with, or were not candidates for, available therapies and who were enrolled in the sap and psp. For all patients, ftd/tpi treatment status, discontinuation reasons, and prior therapies were examined.

Results

The analysis included 717 Canadian patients enrolled in the ftd/tpi sap and psp from September 2017 to October 2018. In that cohort, 59.7% were men, median age was 65 years, and median duration of therapy was 77 days (25%-75% interquartile range: 43-106 days). Of treated patients, 67.1% maintained the same dose for the duration of therapy; 28.0% had a dose reduction.On multivariable analysis, duration of therapy was not influenced by sex, age, province, RAS mutation status, or prior therapies. However, prior oxaliplatin-based chemotherapy (capox or folfox) appeared to be associated with higher rates of discontinuation because of death or disease progression.

Conclusions

In advanced mcrc, ftd/tpi is a well-tolerated therapy. The large number of patients enrolled in the access programs within a short period of time is reflective of major clinical need in this area, with many patients being eligible and interested in pursuing treatment in the refractory setting.

Active treatment in low-risk prostate cancer: a population-based study

Background

Active surveillance instead of active treatment (at) is preferred for patients with low-risk prostate cancer (lr-pca), but practice varies widely. We conducted a population-based study to assess the proportion of patients who underwent at between January 2011 and December 2014, and to evaluate factors associated with at.

Methods

The provincial cancer registry was linked to administrative health datasets to identify patients with lr-pca and to acquire demographic, tumour, and treatment data. The primary outcome was receipt of at during the first 12 months after diagnosis, defined as any receipt of external-beam radiotherapy, brachytherapy, radical prostatectomy, cryotherapy, or androgen deprivation. Univariate and multivariate logistic regression were used to analyze the correlation between patient and tumour factors and at.

Results

Of 1565 patients with lr-pca, 554 (35.4%) underwent at within 12 months of diagnosis. Radical prostatectomy was the most common treatment (58%), followed by brachytherapy (29.6%). Younger age [odds ratio (or) 0.92; 95% confidence interval (ci): 0.91 to 0.94], lower score (≥3) on the Charlson comorbidity index (OR: 0.36; 95% ci: 0.19 to 0.68), T2 stage (or: 3.05; 95% ci: 2.03 to 4.58), higher prostate-specific antigen (psa) at diagnosis (or: 1.13; 95% ci: 1.06 to 1.21), radiation oncologist consultation (or: 3.35; 95% ci: 2.55 to 4.39), and earlier diagnosis year (2012 or: 0.46; 95% ci: 0.34 to 0.63; 2013 or: 0.45; 95% ci: 0.32 to 0.63; 2014 or: 0.33; 95% ci: 0.23 to 0.47) were associated with a higher probability of at.

Conclusions

This contemporary population-based study demonstrates that approximately one third of patients with lr-pca undergo at. Patients of younger age, with less comorbidity, a higher tumour stage, higher psa, earlier year of diagnosis, and radiation oncologist consultation were more likely to undergo at. Further investigation is needed to identify strategies that could minimize overtreatment.

Breast cancer information communicated on a public online platform: an analysis of 'Yahoo! Answer Japan'

INTRODUCTION Japan is a developed country with high use of Internet and online platforms for health information. 'Yahoo! Answer Japan' is the most commonly used question-and-answer service in Japan. AIM To explore the information users seek regarding breast cancer from the 'Yahoo! Answer Japan' web portal. METHODS The 'Yahoo! Answer Japan' portal was searched for the key word 'breast cancer' and all questions searched for the period of 1 January to 31 December 2014 were obtained. The selected questions related to human breast cancer and were not advertisements or promotional material. The questions were categorized using a coding schema. High and low access of the questions were defined by the number of view-counts. RESULTS Among the 2392 selected questions, six major categories were identified; (1) suspected breast cancer, (2) breast cancer screening, (3) treatment of breast cancer, (4) life with breast cancer, (5) prevention of breast cancer and (6) others. The highest number of questions were treatment related (28.8%) followed by suspected breast cancer-related questions (23.4%) and screening-related questions (20%). Statistical analysis revealed that the treatment-related questions were more likely to be highly accessed. CONCLUSION Content analysis of Internet question-answer communities is important, as questions posted on these sites would serve as a rich source of direct reflection regarding the health-related information needs of the general population.

Nonacademic Attributes Predict Medical and Nursing Student Intentions to Emigrate or to Work Rurally: An Eight-Country Survey in Asia and Africa

AbstractWe sought to identify independent, nonacademic predictors of medical and nursing student intent to migrate abroad or from rural to urban areas after graduation in low- and middle-income countries (LMIC). This was a cross-sectional survey of 3,199 first- and final-year medical and nursing students at 16 training institutions in eight LMIC. Questionnaires assessed demographics, career intentions, and preferences regarding selected career, location, and work-related attributes. Using principal component analysis, student preferences were reduced into four discrete categories of priorities: 1) work environment resources, 2) location livability, 3) altruistic job values, and 4) individualistic job values. Students' preferences were scored in each category. Using students' characteristics and priority scores, multivariable proportional odds models were used to derive independent predictors of intentions to emigrate for work outside the country, or to work in a rural area in their native country. Students prioritizing individualistic values more often planned international careers (adjusted odds ratio [aOR] = 1.44, 95% confidence interval [CI] = 1.16-1.78), whereas those prioritizing altruistic values preferred rural careers (aOR = 1.82, 95% CI = 1.50-2.21). Trainees prioritizing high-resource environments preferentially planned careers abroad (aOR = 1.38, 95% CI = 1.12-1.69) and were unlikely to seek rural work (aOR = 0.60, 95% CI = 0.49-0.73). Independent of their priorities, students with prolonged prior rural residence were unlikely to plan emigration (aOR = 0.67, 95% CI = 0.50-0.90) and were more likely to plan a rural career (aOR = 1.53, 95% CI = 1.16-2.03). We conclude that use of nonacademic attributes in medical and nursing admissions processes would likely increase retention in high-need rural areas and reduce emigration "brain drain" in LMIC.

Ramadan fasting is not usually associated with the risk of cardiovascular events: A systematic review and meta-analysis

Over one billion Muslims worldwide fast during the month of Ramadan. Ramadan fasting brings about some changes in the daily lives of practicing Muslims, especially in their diet and sleep patterns, which are associated with the risk of cardiovascular diseases. Over the years, many original studies have made the effort to identify the possible impact of the Ramadan fast on cardiovascular diseases. This systematic review and meta-analysis is an attempt to present the summary of key findings from those articles and an appraisal of selected literature. A systematic search using keywords of “;Ramadan fasting” and “;cardiovascular diseases” was conducted in primary research article and gray-literature repositories, in combination with hand searching and snow balling. Fifteen studies were finally selected for data extraction on the outcomes of stroke, myocardial infarction, and congestive heart failure. The analysis revealed that the incidence of cardiovascular events during the Ramadan fast was similar to the nonfasting period. Ramadan fast is not associated with any change in incidence of acute cardiovascular disease.

Medical and nursing students' intentions to work abroad or in rural areas: a cross-sectional survey in Asia and Africa

OBJECTIVE

To assess medical and nursing students' intentions to migrate abroad or practice in rural areas.

METHODS

We surveyed 3199 first- and final-year medical and nursing students at 16 premier government institutions in Bangladesh, Ethiopia, India, Kenya, Malawi, Nepal, the United Republic of Tanzania and Zambia. The survey contained questions to identify factors that could predict students' intentions to migrate. Primary outcomes were the likelihoods of migrating to work abroad or working in rural areas in the country of training within five years post-training. We assessed predictors of migration intentions using multivariable proportional odds models.

FINDINGS

Among respondents, 28% (870/3156) expected to migrate abroad, while only 18% (575/3158) anticipated a rural career. More nursing than medical students desired professions abroad (odds ratio, OR: 1.76; 95% confidence interval, CI: 1.25-2.48). Career desires before matriculation correlated with current intentions for international (OR: 4.49; 95% CI: 3.21-6.29) and rural (OR: 4.84; 95% CI: 3.52-6.66) careers. Time spent in rural areas before matriculation predicted the preference for a rural career (20 versus 0 years: OR: 1.53, 95% CI: 1.19-1.98) and against work abroad (20 versus 0 years: OR: 0.69, 95% CI: 0.50-0.96).

CONCLUSION

A significant proportion of students surveyed still intend to work abroad or in cities after training. These intentions could be identified even before matriculation. Admissions standards that account for years spent in rural areas could promote greater graduate retention in the country of training and in rural areas.

Robinow syndrome

In 1969, Robinow and colleagues described a syndrome of mesomelic shortening, hemivertebrae, genital hypoplasia, and "fetal facies". Over 100 cases have now been reported and we have reviewed the current knowledge of the clinical and genetic features of the syndrome. The gene for the autosomal recessive form was identified as the ROR2 gene on chromosome 9q22. ROR2 is a receptor tyrosine kinase with orthologues in mouse and other species. The same gene, ROR2, has been shown to cause autosomal dominant brachydactyly B, but it is not known at present whether the autosomal dominant form of Robinow syndrome is also caused by mutations in ROR2.

Amplification of a 13.5-kb region of the PKD1 gene containing the 2.5-kb polypyrimidine tract in intron 21 facilitates mutation detection in this gene

Mutation detection in the PKD1 gene proved to be difficult because two-thirds of the gene is reiterated several times on chromosome 16. Long-range PCR has been used previously to overcome this limitation, but due to a 2.5-kb polypyrimidine tract in intron 21, the screening capacity of the PKD1 gene using this technique was hindered. Here we report the measures that we have used to overcome this limitation.

Novel mutations in the duplicated region of the polycystic kidney disease 1 (PKD1) gene provides supporting evidence for gene conversion

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common human single-gene disorders, and is the most common inherited form of cystic kidney disease. It is estimated that approximately 85% of ADPKD is due to mutations in the PKD1 gene, which is located on chromosome 16p13.3. Mutation analysis in this gene is difficult, because more than two-thirds of reiterated several times at 16p13.1. In this study, mutation screening in 90 ADPKD patients was carried out on exons in the duplicated region of the PKD1 gene (23-34), using genomic long-range PCR followed by nested PCR and single-strand conformation polymorphism (SSCP), and finally cycle sequencing. Two nonconservative missense mutations were detected in exons 25 and 31, and two conservative mutations were found in exons 24 and 29. A novel splicing mutation, which is expected to cause skipping of exon 30, was detected in one case. Moreover, six intronic variants, three silent variants, and one polymorphic variant were detected in this study. Comparison between some of these changes and published sequences from the homologous genes on 16p13.1, revealed supporting evidence for the gene conversion theory as a mechanism responsible for some of the mutations in the PKD1 gene. Factors likely to facilitate gene conversion in this region of the PKD1 gene are discussed.

Lack of association of ACE/angiotensinogen genotype with renal function in autosomal dominant polycystic kidney disease

ACE polymorphisms have recently been shown to associate with worse renal and or cardiovascular outcome, with the D allele widely reported as a risk factor for cardiovascular disease. In autosomal dominant polycystic kidney disease (ADPKD), there are conflicting reports of an association between ACE polymorphisms and disease phenotype. There are no previous reports of any association between angiotensinogen polymorphisms and clinical phenotype in ADPKD. We examined the ACE I/D and angiotensinogen M235T polymorphisms in 176 patients with ADPKD. Patients are categorized into three groups according to the reason for initial investigation. Clinical history and examination findings were recorded at the time of first referral. A cohort of 17 patients had progressive renal impairment observed after 3 or more years of follow-up. Reciprocal creatinine against time was plotted in this group. From the patient population of 176, a total of 33 patients reached end-stage renal failure (ESRF) or a serum creatinine greater than 500 microm/liter. ACE genotype and M235T polymorphism frequencies were compared across groups. Serum creatinine and presence of hypertension and onset of ESRF were taken as outcome variables; age and source of referral were taken as confounding variables. There was no association of any genotype or allele with either creatinine, inverse creatinine, hypertension, or age at end-stage renal failure. These findings do not support the proposition that ACE genotype or angiotensinogen polymorphisms are associated with a worse prognosis in patients with ADPKD.

Recessive Robinow syndrome, allelic to dominant brachydactyly type B, is caused by mutation of ROR2

The autosomal recessive form of Robinow syndrome (RRS; MIM 268310) is a severe skeletal dysplasia with generalized limb bone shortening, segmental defects of the spine, brachydactyly and a dysmorphic facial appearance. We previously mapped the gene mutated in RRS to chromosome 9q22 (ref. 4), a region that overlaps the locus for autosomal dominant brachydactyly type B (refs 5,6). The recent identification of ROR2, encoding an orphan receptor tyrosine kinase, as the gene mutated in brachydactyly type B (BDB1; ref. 7) and the mesomelic dwarfing in mice homozygous for a lacZ and/or a neo insertion into Ror2 (refs 8,9) made this gene a candidate for RRS. Here we report homozygous missense mutations in both intracellular and extracellular domains of ROR2 in affected individuals from 3 unrelated consanguineous families, and a nonsense mutation that removes the tyrosine kinase domain and all subsequent 3' regions of the gene in 14 patients from 7 families from Oman. The nature of these mutations suggests that RRS is caused by loss of ROR2 activity. The identification of mutations in three distinct domains (containing Frizzled-like, kringle and tyrosine kinase motifs) indicates that these are all essential for ROR2 function.

Location of mutations within the PKD2 gene influences clinical outcome

BACKGROUND

Since the cloning of the gene for autosomal dominant polycystic kidney disease type 2 (PKD2), approximately 40 different mutations of that gene have been reported to be associated with the disease. The relationship between the PKD2 genotype and phenotype, however, remains unclear.

METHODS

Detailed clinical information was collected for PKD2 families in which the underlying mutation had been identified. Logistic regression analysis was employed to assess the influence of age and sex on hypertension, hematuria, renal calculi, and urinary tract infections, and a clinical phenotype score was computed. Patients were then grouped according to the relative location of their mutation within the cDNA sequence, and differences in the mean phenotypic score between groups were tested for statistical significance by means of a multiple pairwise t-test.

RESULTS

While phenotypic scores for each mutational group revealed a considerable degree of intragroup variability, the variability in phenotypic scores was significantly higher between mutational groups than within groups. A group-wise comparison of the mean phenotypic scores confirmed the observation of significant nonlinear variation in disease severity, with high- and low-scoring mutational groups interspersed along the gene sequence.

CONCLUSION

The identification of groups of mutations in the PKD2 gene, which differ significantly with respect to clinical outcome, is to our knowledge the first description of a genotype/phenotype correlation in autosomal dominant polycystic kidney disease. It also provides evidence against complete loss of function of the mutant PKD2 gene product.

Linkage of recessive Robinow syndrome to a 4 cM interval on chromosome 9q22

Autosomal recessive Robinow syndrome is a form of mesomelic dwarfism with multiple rib and vertebral anomalies. Using autozygosity mapping we have identified a genetic locus (RBNW1) for this syndrome at chromosome 9q22 in seven consanguineous families from Oman. Our results indicate that the gene lies within a 4 cM region between markers D9S1836 and D9S1803 (maximum multipoint LOD score 12.3). In addition, we have analysed two non-Omani families with autosomal recessive Robinow and found no genetic heterogeneity.

ACE gene polymorphism and survival in atherosclerotic renovascular disease

Renovascular disease (RVD) is an important cause of end-stage renal disease and is associated with a high mortality rate, mostly because of coexisting cardiovascular and cerebrovascular disease. The deletion (DD) polymorphism of the angiotensin-converting enzyme (ACE) gene has been described in association with severe vascular disease affecting major organs. To investigate whether DD genotype is a risk factor for mortality in RVD, we performed a follow-up study of 61 patients with this disease. Patients (age, 68.0 +/- 6.5 years) affected by atherosclerotic vascular disease were enrolled after angiographic demonstration of a renal artery stenosis. The average follow-up was 48.1 +/- 14.9 months. Genotype was insertion/deletion (I/D) in 30 patients, DD in 27 patients, and II in 4 patients. At enrollment, a complete assessment of heart, blood vessels, and renal function was performed. During the follow-up period, 13 patients died (9 DD, 4 ID) and 7 patients evolved into end-stage renal failure. The cumulative survival rate at 5 years was 45.4% +/- 13.4%. Factors associated with mortality were analyzed with Cox proportional hazard regression. The multivariate analysis showed that DD genotype, severe carotid disease, and smoking were independent predictors of mortality. The multivariate analysis of predictors of renal failure showed that the only significant association was found with baseline serum creatinine level of 265 micromol/L or greater. We conclude that the DD genotype of the ACE gene is a marker for mortality in RVD.

Angiotensin-converting enzyme gene I/D polymorphism and carotid artery disease in renovascular hypertension

There is evidence linking the activation of the renin-angiotensin system (RAS) with target organ damage in renovascular hypertension (RVH). A genetic association of the DD genotype of the angiotensin-converting enzyme (ACE) gene with cardiovascular complications has been found in various clinical conditions. The aim of our study was to determine whether the insertion/deletion (I/D) polymorphism of the ACE gene is associated with the high prevalence of target organ damage reported in RVH. A total of 65 atherosclerotic patients (age 68.2 +/- 5.2 years) with RVH and 49 atherosclerotic patients (age 68.0 +/- 6.3 years) with essential hypertension (EH) were sequentially enrolled when attending the outpatient clinic for specialist assessment of their vascular disorder. Cardiac, renal, and vascular involvement were assessed in both groups and blood was taken for genetic analysis. Patients with RVH had a higher prevalence of left ventricular hypertrophy (LVH), carotid artery disease, and albuminuria than those with EH. In RVH, but not in EH, the DD genotype was significantly associated with severe arterial disease. In RVH, carotid disease (lumen narrowing >60%) was present in 62% of DD patients versus 25% of the other genotypes (OR = 4.90, 95% CI: 1.70-14.13). Such an association was also present in peripheral vascular disease: 72.4% in DD patients versus 41.6% in the other genotypes (OR = 3.67, 95% CI = 1.29-10.36). Logistic regression analysis showed that the DD genotype was the strongest predictor of risk of severe carotid disease. We conclude that, in atherosclerotic RVH, there is an association of the severity of vascular disease with the DD genotype of the ACE gene.

Novel mutations in the 3 region of the polycystic kidney disease 1 (PKD1) gene

Mutation screening in 90 unrelated ADPKD1 patients was carried out on some of the exons in the single copy area (37, 38, 39, 44, 45) using genomic PCR and SSCP. Four novel mutations were found: a 15 bp in-frame deletion in exon 39 [nt11449 (del 15)], a 2 bp deletion in exon 44 [nt12252 (del 2)], a G insertion in exon 44 [nt12290 (Ins G)], and a GTT in-frame deletion in exon 45 [nt12601 (del 3)].

Splicing mutations in KCNQ1: a mutation hot spot at codon 344 that produces in frame transcripts

BACKGROUND

Long-QT syndrome is a monogenic disorder that produces cardiac arrhythmias and can lead to sudden death. At least 5 loci and 4 known genes exist in which mutations have been shown to be responsible for the disease. The potassium channel gene KCNQ1, previously named KVLQT1, on chromosome 11p15.5 is one of these.

METHODS AND RESULTS

We initially analyzed one family using microsatellite markers and found linkage to KCNQ1. Mutation detection showed a G to C change in the last base of exon 6 (1032 G-->C) that does not alter the coded alanine. Restriction digest analysis in the family showed that only affected individuals carried the mutation. A previous report suggested that a G to A substitution at the same position may act as a splice mutation in KCNQ1, but no data was given to support this hypothesis nor was the transcription product identified. We have shown by reverse-transcription polymerase chain reaction that 2 smaller bands were produced for the KCNQ1 gene transcripts in addition to the normal-sized transcripts when lymphocytes of affected individuals were analyzed. Sequencing these transcripts showed a loss of exon 7 in one and exons 6 and 7 in the other, but an in-frame transcript was left in each instance. We examined other families in whom long-QT syndrome was diagnosed and found another unreported splice-site mutation, 922-1 G-->C, in the acceptor site of intron 5, and 2 of the previously reported 1032 G-->A mutations. All these showed a loss of exons 6 and 7 in the mutant transcripts, validating the proposal that a consensus sequence is affected in the exonic mutations and that the integrity of the base at position 1032 is essential for correct processing of the transcript.

CONCLUSIONS

The 6 cases already reported in the literature with the 1032 G-->A transition, the novel 1032 G-->C transversion, and a recent G-->T transversion at the same base show that codon 344 is the second most frequently mutated after codon 341, suggesting at least two hotspots for mutations in KCNQ1.