Can first-year medical students acquire quality improvement knowledge prior to substantial clinical exposure? A mixed-methods evaluation of a pre-clerkship curriculum that uses education as the context for learning.

BACKGROUND: Quality Improvement (QI) training for health professionals is essential to strengthen health systems. However, QI training during medical school is constrained by students' lack of contextual understanding of the health system and an already saturated medical curriculum. The Program for Improvement in Medical Education (PRIME), an extracurricular offered at the Michael G. DeGroote School of Medicineat McMaster University (Hamilton, Canada), addresses these obstacles by having first-year medical students engage in QI by identifying opportunities for improvement within their own education. METHODS: A sequential explanatory mixed-methods approach, which combines insights derived from quantitative instruments and qualitative interview methods, was used to examine the impact of PRIME on first-year medical students and the use of QI in the context of education. RESULTS: The study reveals that participation in PRIME increases both knowledge of, and comfort with, fundamental QI concepts, even when applied to clinical scenarios. Participants felt that education provided a meaningful context to learn QI at this stage of their training, and were motivated to participate in future QI projects to drive real-world improvements in the health system. CONCLUSIONS: Early exposure to QI principles that uses medical education as the context may be an effective intervention to foster QI competencies at an early stage and ultimately promote engagement in clinical QI. Moreover, PRIME also provides a mechanism to drive improvements in medical education. Future research is warranted to better understand the impact of education as a context for later engagement in clinical QI applications as well as the potential for QI methods to be translated directly into education.

Corticospinal excitability is associated with hypocapnia but not changes in cerebral blood flow.

KEY POINTS: Reductions in cerebral blood flow (CBF) may be implicated in the development of neuromuscular fatigue; however, the contribution from hypocapnic-induced reductions (i.e. P ETC O2) in CBF versus reductions in CBF per se has yet to be isolated. We assessed neuromuscular function while using indomethacin to selectively reduce CBF without changes in P ETC O2 and controlled hyperventilation-induced hypocapnia to reduce both CBF and P ETC O2. Increased corticospinal excitability appears to be exclusive to reductions in P ETC O2 but not reductions in CBF, whereas sub-optimal voluntary output from the motor cortex is moderately associated with decreased CBF independent of changes in P ETC O2. These findings suggest that changes in CBF and P ETC O2 have distinct roles in modulating neuromuscular function. ABSTRACT: Although reductions in cerebral blood flow (CBF) may be involved in central fatigue, the contribution from hypocapnia-induced reductions in CBF versus reductions in CBF per se has not been isolated. This study examined whether reduced arterial PCO2 (P aC O2), independent of concomitant reductions in CBF, impairs neuromuscular function. Neuromuscular function, as indicated by motor-evoked potentials (MEPs), maximal M-wave (Mmax ) and cortical voluntary activation (cVA) of the flexor carpi radialis muscle during isometric wrist flexion, was assessed in ten males (29 ± 10 years) during three separate conditions: (1) cyclooxygenase inhibition using indomethacin (Indomethacin, 1.2 mg kg(-1) ) to selectively reduce CBF by 28.8 ± 10.3% (estimated using transcranial Doppler ultrasound) without changes in end-tidal PCO2 (P ETC O2); (2) controlled iso-oxic hyperventilation-induced reductions in P aC O2 (Hypocapnia), P ETC O2  = 30.1 ± 4.5 mmHg with related reductions in CBF (21.7 ± 6.3%); and (3) isocapnic hyperventilation (Isocapnia) to examine the potential direct influence of hyperventilation-mediated activation of respiratory control centres on CBF and changes in neuromuscular function. Change in MEP amplitude (%Mmax ) from baseline was greater in Hypocapnia tha in Isocapnia (11.7 ± 9.8%, 95% confidence interval (CI) [2.6, 20.7], P = 0.01) and Indomethacin (13.3 ± 11.3%, 95% CI [2.8, 23.7], P = 0.01) with a large Cohen's effect size (d ≥ 1.17). Although not statistically significant, cVA was reduced with a moderate effect size in Indomethacin (d = 0.7) and Hypocapnia (d = 0.9) compared to Isocapnia. In summary, increased corticospinal excitability - as reflected by larger MEP amplitude - appears to be exclusive to reduced P aC O2, but not reductions in CBF per se. Sub-optimal voluntary output from the motor cortex is moderately associated with decreased CBF, independent of reduced P aC O2.

Feasibility of a randomized controlled trial to evaluate the impact of decision boxes on shared decision-making processes.

BACKGROUND: Decision boxes (DBoxes) are two-page evidence summaries to prepare clinicians for shared decision making (SDM). We sought to assess the feasibility of a clustered Randomized Controlled Trial (RCT) to evaluate their impact. METHODS: A convenience sample of clinicians (nurses, physicians and residents) from six primary healthcare clinics who received eight DBoxes and rated their interest in the topic and satisfaction. After consultations, their patients rated their involvement in decision-making processes (SDM-Q-9 instrument). We measured clinic and clinician recruitment rates, questionnaire completion rates, patient eligibility rates, and estimated the RCT needed sample size. RESULTS: Among the 20 family medicine clinics invited to participate in this study, four agreed to participate, giving an overall recruitment rate of 20%. Of 148 clinicians invited to the study, 93 participated (63%). Clinicians rated an interest in the topics ranging 6.4-8.2 out of 10 (with 10 highest) and a satisfaction with DBoxes of 4 or 5 out of 5 (with 5 highest) for 81% DBoxes. For the future RCT, we estimated that a sample size of 320 patients would allow detecting a 9% mean difference in the SDM-Q-9 ratings between our two arms (0.02 ICC; 0.05 significance level; 80% power). CONCLUSIONS: Clinicians' recruitment and questionnaire completion rates support the feasibility of the planned RCT. The level of interest of participants for the DBox topics, and their level of satisfaction with the Dboxes demonstrate the acceptability of the intervention. Processes to recruit clinics and patients should be optimized.

Does bracing affect bone health in women with adolescent idiopathic scoliosis?

PURPOSE: Adolescent idiopathic scoliosis (AIS) is often associated with low bone mineral content and density (BMC, BMD). Bracing, used to manage spine curvature, may interfere with the growth-related BMC accrual, resulting in reduced bone strength into adulthood. The purpose of this study was to assess the effects of brace treatment on BMC in adult women, diagnosed with AIS and braced in early adolescence. METHODS: Participants included women with AIS who: (i) underwent brace treatment (AIS-B, n = 15, 25.6 ± 5.8 yrs), (ii) underwent no treatment (AIS, n = 15, 24.0 ± 4.0 yrs), and (iii) a healthy comparison group (CON, n = 19, 23.5 ± 3.8 yrs). BMC and body composition were assessed using dual-energy X-ray absorptiometry. Differences between groups were examined using a oneway ANOVA or ANCOVA, as appropriate. RESULTS: AIS-B underwent brace treatment 27.9 ± 21.6 months, for 18.0 ± 5.4 h/d. Femoral neck BMC was lower (p = 0.06) in AIS-B (4.54 ± 0.10 g) compared with AIS (4.89 ± 0.61 g) and CON (5.07 ± 0.58 g). Controlling for lean body mass, calcium and vitamin D daily intake, and strenuous physical activity, femoral neck BMC was statistically different (p = 0.02) between groups. A similar pattern was observed at other lower extremity sites (p < 0.05), but not in the spine or upper extremities. BMC and BMD did not correlate with duration of brace treatment, duration of daily brace wear, or overall physical activity. CONCLUSION: Young women with AIS, especially those who were treated with a brace, have significantly lower BMC in their lower limbs compared to women without AIS. However, the lack of a relationship between brace treatment duration during adolescence and BMC during young adulthood, suggests that the brace treatment is not the likely mechanism of the low BMC.

Evidence summaries (decision boxes) to prepare clinicians for shared decision-making with patients: a mixed methods implementation study.

BACKGROUND: Decision boxes (Dboxes) provide clinicians with research evidence about management options for medical questions that have no single best answer. Dboxes fulfil a need for rapid clinical training tools to prepare clinicians for clinician-patient communication and shared decision-making. We studied the barriers and facilitators to using the Dbox information in clinical practice. METHODS: We used a mixed methods study with sequential explanatory design. We recruited family physicians, residents, and nurses from six primary health-care clinics. Participants received eight Dboxes covering various questions by email (one per week). For each Dbox, they completed a web questionnaire to rate clinical relevance and cognitive impact and to assess the determinants of their intention to use what they learned from the Dbox to explain to their patients the advantages and disadvantages of the options, based on the theory of planned behaviour (TPB). Following the 8-week delivery period, we conducted focus groups with clinicians and interviews with clinic administrators to explore contextual factors influencing the use of the Dbox information. RESULTS: One hundred clinicians completed the web surveys. In 54% of the 496 questionnaires completed, they reported that their practice would be improved after having read the Dboxes, and in 40%, they stated that they would use this information for their patients. Of those who would use the information for their patients, 89% expected it would benefit their patients, especially in that it would allow the patient to make a decision more in keeping with his/her personal circumstances, values, and preferences. They intended to use the Dboxes in practice (mean 5.6±1.2, scale 1-7, with 7 being "high"), and their intention was significantly related to social norm, perceived behavioural control, and attitude according to the TPB (P<0.0001). In focus groups, clinicians mentioned that co-interventions such as patient decision aids and training in shared decision-making would facilitate the use of the Dbox information. Some participants would have liked a clear "bottom line" statement for each Dbox and access to printed Dboxes in consultation rooms. CONCLUSIONS: Dboxes are valued by clinicians. Tailoring of Dboxes to their needs would facilitate their implementation in practice.

The effect of clinical teaching on patient satisfaction in rural and community settings.

INTRODUCTION: Few studies have examined the effect of clinical teaching on patient satisfaction in rural and community-based settings. We sought to examine whether patient satisfaction differed when patients were seen by a physician alone or by a physician and medical student in these settings. METHODS: We conducted a cross-sectional study in rural and community-based settings in southern Ontario (3 obstetrician-gynecologist offices and 4 family medicine clinics). Patients seen by a physician with or without a medical student present completed satisfaction and attitudes questionnaires about their experience. RESULTS: Patient satisfaction was high across both groups and did not differ when segregated by patient age, sex or employment status. Satisfaction scores were similar for patients seen by a physician with or without a student present. Satisfaction scores did not differ based on practice location. Patients' reasons for agreeing to be seen by a medical student included helping to teach students about medical concerns and helping to train future doctors. CONCLUSION: Patients in rural and community-based outpatient settings were satisfied with their care when a medical student was involved.

INTRODUCTION: Peu d'études ont analysé l'effet de l'enseignement clinique sur la satisfaction des patients en milieux rural et communautaire. Nous avons cherché à déterminer si la satisfaction des patients différait lorsqu'ils étaient accueillis par un médecin seul ou par un médecin et un étudiant en médecine dans ces contextes. MÉTHODES: Nous avons réalisé une étude transversale en milieux rural et communautaire du sud de l'Ontario (3 bureaux d'obstétriciens-gynécologues et 4 cliniques de médecine familiale). Les patients reçus par un médecin accompagné ou non d'un étu - diant en médecine ont rempli des questionnaires sur la satisfaction et les attitudes au sujet de leur expérience. RÉSULTATS: La satisfaction des patients était élevée dans les deux groupes et ne différait pas lorsqu'elle était distinguée selon l'âge et le sexe du patient ou le statut d'emploi. Les scores de satisfaction étaient semblables pour les patients reçus par un médecin accompagné ou non d'un étudiant. Les scores de satisfaction n'ont pas différé en fonction du lieu de pratique. Les raisons pour lesquelles les patients ont accepté d'être vus par un étudiant en médecine comprenaient le fait d'aider à donner aux étudiants de la formation au sujet de problèmes médicaux et d'aider à former de futurs médecins. CONCLUSION: Les patients reçus en clinique externe dans les milieux rural et communautaire étaient satisfaits des soins reçus lorsqu'un étudiant en médecine était présent.

Bionimbus: a cloud for managing, analyzing and sharing large genomics datasets.

BACKGROUND: As large genomics and phenotypic datasets are becoming more common, it is increasingly difficult for most researchers to access, manage, and analyze them. One possible approach is to provide the research community with several petabyte-scale cloud-based computing platforms containing these data, along with tools and resources to analyze it. METHODS: Bionimbus is an open source cloud-computing platform that is based primarily upon OpenStack, which manages on-demand virtual machines that provide the required computational resources, and GlusterFS, which is a high-performance clustered file system. Bionimbus also includes Tukey, which is a portal, and associated middleware that provides a single entry point and a single sign on for the various Bionimbus resources; and Yates, which automates the installation, configuration, and maintenance of the software infrastructure required. RESULTS: Bionimbus is used by a variety of projects to process genomics and phenotypic data. For example, it is used by an acute myeloid leukemia resequencing project at the University of Chicago. The project requires several computational pipelines, including pipelines for quality control, alignment, variant calling, and annotation. For each sample, the alignment step requires eight CPUs for about 12 h. BAM file sizes ranged from 5 GB to 10 GB for each sample. CONCLUSIONS: Most members of the research community have difficulty downloading large genomics datasets and obtaining sufficient storage and computer resources to manage and analyze the data. Cloud computing platforms, such as Bionimbus, with data commons that contain large genomics datasets, are one choice for broadening access to research data in genomics.

Barriers and facilitators to implementing Decision Boxes in primary healthcare teams to facilitate shared decisionmaking: a study protocol.

BACKGROUND: Decision Boxes are summaries of the most important benefits and harms of health interventions provided to clinicians before they meet the patient, to prepare them to help patients make informed and value-based decisions. Our objective is to explore the barriers and facilitators to using Decision Boxes in clinical practice, more precisely factors stemming from (1) the Decision Boxes themselves, (2) the primary healthcare team (PHT), and (3) the primary care practice environment. METHODS/DESIGN: A two-phase mixed methods study will be conducted. Eight Decision Boxes relevant to primary care, and written in both English and in French, will be hosted on a website together with a tutorial to introduce the Decision Box. The Decision Boxes will be delivered as weekly emails over a span of eight weeks to clinicians of PHTs (family physicians, residents and nurses) in five primary care clinics located across two Canadian provinces. Using a web-questionnaire, clinicians will rate each Decision Box with the Information Assessment Method (cognitive impacts, relevance, usefulness, expected benefits) and with a questionnaire based on the Theory of Planned Behavior to study the determinants of clinicians' intention to use what they learned from that Decision Box in their patient encounter (attitude, social norm, perceived behavioral control). Web-log data will be used to monitor clinicians' access to the website. Following the 8-week intervention, we will conduct semi-structured group interviews with clinicians and individual interviews with clinic administrators to explore contextual factors influencing the use of the Decision Boxes. Data collected from questionnaires, focus groups and individual interviews will be combined to identify factors potentially influencing implementation of Decision Boxes in clinical practice by clinicians of PHTs. CONCLUSIONS: This project will allow tailoring of Decision Boxes and their delivery to overcome the specific barriers identified by clinicians of PHTs to improve the implementation of shared decision making in this setting.

Angiogenin levels and ANG genotypes: dysregulation in amyotrophic lateral sclerosis.

OBJECTIVE: To determine whether 5 single nucleotide polymorphisms (SNPs) associate with ALS in 3 different populations. We also assessed the contribution of genotype to angiogenin levels in plasma and CSF. METHODS: Allelic association statistics were calculated for polymorphisms in the ANG gene in 859 patients and 1047 controls from Sweden, Ireland and Poland. Plasma, serum and CSF angiogenin levels were quantified and stratified according to genotypes across the ANG gene. The contribution of SNP genotypes to variance in circulating angiogenin levels was estimated in patients and controls. RESULTS: All SNPs showed association with ALS in the Irish group. The SNP rs17114699 replicated in the Swedish cohort. No SNP associated in the Polish cohort. Age- and sex-corrected circulating angiogenin levels were significantly lower in patients than in controls (p<0.001). An allele dose-dependent regulation of angiogenin levels was observed in controls. This regulation was attenuated in the ALS cohort. A significant positive correlation between CSF plasma angiogenin levels was present in controls and abolished in ALS. CONCLUSIONS: ANG variants associate with ALS in the Irish and Swedish populations, but not in the Polish. There is evidence of dysregulation of angiogenin expression in plasma and CSF in sporadic ALS. Angiogenin expression is likely to be important in the pathogenesis of ALS.

Control of motoneuron survival by angiogenin.

Mutations in the hypoxia-inducible factor angiogenin (ANG) have been identified in Amyotrophic Lateral Sclerosis (ALS) patients, but the potential role of ANG in ALS pathogenesis was undetermined. Here we show that angiogenin promotes motoneuron survival both in vitro and in vivo. Angiogenin protected cultured motoneurons against excitotoxic injury in a PI-3-kinase/Akt kinase-dependent manner, whereas knock-down of angiogenin potentiated excitotoxic motoneuron death. Expression of wild-type ANG protected against endoplasmic reticulum (ER) stress-induced and trophic-factor-withdrawal-induced cell death in vitro, whereas the ALS-associated ANG mutant K40I exerted no protective activity and failed to activate Akt-1. In SOD1(G93A) mice angiogenin delivery increased lifespan and motoneuron survival, restored the disease-associated decrease in Akt-1 survival signaling, and reversed a pathophysiological increase in ICAM-1 expression. Our data demonstrate that angiogenin is a key factor in the control of motoneuron survival.

50bp deletion in the promoter for superoxide dismutase 1 (SOD1) reduces SOD1 expression in vitro and may correlate with increased age of onset of sporadic amyotrophic lateral sclerosis.

The objective was to test the hypothesis that a described association between homozygosity for a 50bp deletion in the SOD1 promoter 1684bp upstream of the SOD1 ATG and an increased age of onset in SALS can be replicated in additional SALS and control sample sets from other populations. Our second objective was to examine whether this deletion attenuates expression of the SOD1 gene. Genomic DNA from more than 1200 SALS cases from Ireland, Scotland, Quebec and the USA was genotyped for the 50bp SOD1 promoter deletion. Reporter gene expression analysis, electrophoretic mobility shift assays and chromatin immunoprecipitation studies were utilized to examine the functional effects of the deletion. The genetic association for homozygosity for the promoter deletion with an increased age of symptom onset was confirmed overall in this further study (p=0.032), although it was only statistically significant in the Irish subset, and remained highly significant in the combined set of all cohorts (p=0.001). Functional studies demonstrated that this polymorphism reduces the activity of the SOD1 promoter by approximately 50%. In addition we revealed that the transcription factor SP1 binds within the 50bp deletion region in vitro and in vivo. Our findings suggest the hypothesis that this deletion reduces expression of the SOD1 gene and that levels of the SOD1 protein may modify the phenotype of SALS within selected populations.

Screening of hypoxia-inducible genes in sporadic ALS.

Genetic variations in two hypoxia-inducible angiogenic genes, VEGF and ANG, have been linked with sporadic amyotrophic lateral sclerosis (SALS). Common variations in these genes may reduce the levels or functioning of their products. VEGF and ANG belong to a larger group of angiogenic genes that are up-regulated under hypoxic conditions. We hypothesized that common genetic variation across other members of this group may also predispose to sporadic ALS. To screen other hypoxia-inducible angiogenic genes for association with SALS, we selected 112 tagging single nucleotide polymorphisms (tgSNPs) that captured the common genetic variation across 16 VEGF-like and eight ANG-like hypoxia-inducible genes. Screening for association was performed in 270 Irish individuals with typical SALS and 272 ethnically matched unrelated controls. SNPs showing association in the Irish phase were genotyped in a replication sample of 281 Swedish sporadic ALS patients and 286 Swedish controls. Seven markers showed association in the Irish. The one modest replication signal observed in the Swedish replication sample, at rs3801158 in the gene inhibin beta A, was for the opposite allele vs. the Irish cohort. We failed to detect association of common variation across 24 candidate hypoxia-inducible angiogenic genes with SALS.

Evaluation of the Golgi trafficking protein VPS54 (wobbler) as a candidate for ALS.

VPS54 is a component of the Golgi-associated retrograde protein (GARP) complex of vesicle sorting proteins. A missense mutation of Vps54 is responsible for motor neuron disease in the wobbler mouse, but the human gene on chromosome 2p14-15 has not been evaluated as a disease gene. We completely sequenced the 22 coding exons from 96 individuals with sporadic ALS, 96 individuals with familial ALS, and 96 controls. Twenty-one novel SNPs were identified. The non-synonymous variant, T360A, was observed in one patient and 0/910 controls. Several polymorphic non-synonymous SNPs were also observed in patients and controls. These initial data suggest that mutations in VPS54 are not a major cause of ALS.

A genome-wide association study of sporadic ALS in a homogenous Irish population.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive limb or bulbar weakness. Efforts to elucidate the disease-associated loci have to date produced conflicting results. One strategy to improve power in genome-wide studies is to genotype a genetically homogenous population. Such a population exhibits extended linkage disequilibrium (LD) and lower allelic heterogeneity to facilitate disease gene mapping. We sought to identify associated variants for ALS in the Irish, a stable population of relatively homogenous genetic background, and to replicate these findings in larger genetically out-bred populations. We conducted a genome-wide association study in 432 Irish individuals using Illumina HumanHap 550K single nucleotide polymorphism chips. We demonstrated extended LD and increased homogeneity in the Irish sample when compared to an out-bred population of mixed European ancestry. The Irish scan identified 35 loci associated with P-values below 0.0001. For replication, we identified seven chromosomal regions commonly associated in a joint analysis of genome-wide data on 958 ALS cases and 932 controls from Ireland and the previously published datasets from the US and The Netherlands. When pooled, the strongest association was a variant in the gene encoding DPP6, a component of type A neuronal transmembrane potassium channels. Further confirmation of the candidate loci is warranted in additional genome-wide datasets. We have made our individual genotyping data publicly available, contributing to a powerful world-wide resource to refine our understanding of the genetics of sporadic ALS.

Paraoxonase promoter and intronic variants modify risk of sporadic amyotrophic lateral sclerosis.

BACKGROUND: The paraoxonases, PON1-3, play a major protective role both against environmental toxins and as part of the antioxidant defence system. Recently, non-synonymous coding single nucleotide polymorphisms (SNPs), known to lower serum PON activity, have been associated with sporadic ALS (SALS) in a Polish population. A separate trio based study described a detrimental allele at the PON3 intronic variant INS2+3651 (rs10487132). Association between PON gene cluster variants and SALS requires external validation in an independent dataset. AIMS: To examine the association of the promoter SNPs PON1(-162G>A) and PON1(-108T>C); the non-synonymous functional SNPs PON1(Q192R and L55M) and PON2(C311S and A148G); and the intronic marker PON3(INS2+3651A>G), with SALS in a genetically homogenous population. METHODS: 221 Irish patients with SALS and 202 unrelated control subjects were genotyped using KASPar chemistries. Statistical analyses and haplotype estimations were conducted using Haploview and Unphased software. Multiple permutation testing, as implemented in Unphased, was applied to haplotype p values to correct for multiple hypotheses. RESULTS: Two of the seven SNPs were associated with SALS in the Irish population: PON1(55M) (OR 1.52, p = 0.006) and PON3(INS2+3651 G) (OR 1.36, p = 0.03). Two locus haplotype analysis showed association only when both of these risk alleles were present (OR 1.7, p = 0.005), suggesting a potential effect modification. Low functioning promoter variants were observed to influence this effect when compared with wild-type. CONCLUSIONS: These data provide additional evidence that genetic variation across the paroxanase loci may be common susceptibility factors for SALS.

Heterogeneity of presentation and outcome in the Irish rapid-onset dystonia-parkinsonism kindred.

The authors report a 7-year follow-up video study and molecular data on the Irish rapid-onset dystonia-Parkinsonism kindred. All affected patients tested had a missense mutation in the Na(+)/K(+) -ATPase alpha3 subunit (ATP1A3), twice previously identified, suggestive of a mutation hotspot. Clinical presentation, progression, and outcome in this kindred is varied. Some patients remain stable over many years, others worsen, have a fluctuating course, or improve over time. To date there have been no effective treatments for this disorder, although Na(+)/K(+) ATPase may be a future therapeutic target. The broad phenotypic spectrum of RDP described in the text and detailed in the video, should be considered when evaluating patients with dystonia.

Analysis of IFT74 as a candidate gene for chromosome 9p-linked ALS-FTD.

BACKGROUND: A new locus for amyotrophic lateral sclerosis--frontotemporal dementia (ALS-FTD) has recently been ascribed to chromosome 9p. METHODS: We identified chromosome 9p segregating haplotypes within two families with ALS-FTD (F476 and F2) and undertook mutational screening of candidate genes within this locus. RESULTS: Candidate gene sequencing at this locus revealed the presence of a disease segregating stop mutation (Q342X) in the intraflagellar transport 74 (IFT74) gene in family 476 (F476), but no mutation was detected within IFT74 in family 2 (F2). While neither family was sufficiently informative to definitively implicate or exclude IFT74 mutations as a cause of chromosome 9-linked ALS-FTD, the nature of the mutation observed within F476 (predicted to truncate the protein by 258 amino acids) led us to sequence the open reading frame of this gene in a large number of ALS and FTD cases (n = 420). An additional sequence variant (G58D) was found in a case of sporadic semantic dementia. I55L sequence variants were found in three other unrelated affected individuals, but this was also found in a single individual among 800 Human Diversity Gene Panel samples. CONCLUSION: Confirmation of the pathogenicity of IFT74 sequence variants will require screening of other chromosome 9p-linked families.