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Primary open-angle glaucoma (POAG) is a degenerative eye disease for which early treatment is critical to mitigate visual impairment and irreversible blindness. POAG-associated loci individually confer incremental risk. Genetic risk score(s) (GRS) could enable POAG risk stratification. Despite significantly higher POAG burden among individuals of African ancestry (AFR), GRS are limited in this population. A recent large-scale, multi-ancestry meta-analysis identified 127 POAG-associated loci and calculated cross-ancestry and ancestry-specific effect estimates, including in European ancestry (EUR) and AFR individuals. We assessed the utility of the 127-variant GRS for POAG risk stratification in EUR and AFR Veterans in the Million Veteran Program (MVP). We also explored the association between GRS and documented invasive glaucoma surgery (IGS).Cross-sectional study.MVP Veterans with imputed genetic data, including 5830 POAG cases (445 with IGS documented in the electronic health record) and 64 476 controls.We tested unweighted and weighted GRS of 127 published risk variants in EUR (3382 cases and 58 811 controls) and AFR (2448 cases and 5665 controls) Veterans in the MVP. Weighted GRS were calculated using effect estimates from the most recently published report of cross-ancestry and ancestry-specific meta-analyses. We also evaluated GRS in POAG cases with documented IGS.Performance of 127-variant GRS in EUR and AFR Veterans for POAG risk stratification and association with documented IGS.GRS were significantly associated with POAG (Plt; 5 × 10sup-5/sup) in both groups; a higher proportion of EUR compared with AFR were consistently categorized in the top GRS decile (21.9%-23.6% and 12.9%-14.5%, respectively). Only GRS weighted by ancestry-specific effect estimates were associated with IGS documentation in AFR cases; all GRS types were associated with IGS in EUR cases.Varied performance of the GRS for POAG risk stratification and documented IGS association in EUR and AFR Veterans highlights (1) the complex risk architecture of POAG, (2) the importance of diverse representation in genomics studies that inform GRS construction and evaluation, and (3) the necessity of expanding diverse POAG-related genomic data so that GRS can equitably aid in screening individuals at high risk of POAG and who may require more aggressive treatment.

Supplemental Digital Content is available in the text., Background: Abdominal aortic aneurysm (AAA) is an important cause of cardiovascular mortality; however, its genetic determinants remain incompletely defined. In total, 10 previously identified risk loci explain a small fraction of AAA heritability. Methods: We performed a genome-wide association study in the Million Veteran Program testing ≈18 million DNA sequence variants with AAA (7642 cases and 172 172 controls) in veterans of European ancestry with independent replication in up to 4972 cases and 99 858 controls. We then used mendelian randomization to examine the causal effects of blood pressure on AAA. We examined the association of AAA risk variants with aneurysms in the lower extremity, cerebral, and iliac arterial beds, and derived a genome-wide polygenic risk score (PRS) to identify a subset of the population at greater risk for disease. Results: Through a genome-wide association study, we identified 14 novel loci, bringing the total number of known significant AAA loci to 24. In our mendelian randomization analysis, we demonstrate that a genetic increase of 10 mm Hg in diastolic blood pressure (odds ratio, 1.43 [95% CI, 1.24–1.66]; P=1.6×10−6), as opposed to systolic blood pressure (odds ratio, 1.06 [95% CI, 0.97–1.15]; P=0.2), likely has a causal relationship with AAA development. We observed that 19 of 24 AAA risk variants associate with aneurysms in at least 1 other vascular territory. A 29-variant PRS was strongly associated with AAA (odds ratioPRS, 1.26 [95% CI, 1.18–1.36]; PPRS=2.7×10−11 per SD increase in PRS), independent of family history and smoking risk factors (odds ratioPRS+family history+smoking, 1.24 [95% CI, 1.14–1.35]; PPRS=1.27×10−6). Using this PRS, we identified a subset of the population with AAA prevalence greater than that observed in screening trials informing current guidelines. Conclusions: We identify novel AAA genetic associations with therapeutic implications and identify a subset of the population at significantly increased genetic risk of AAA independent of family history. Our data suggest that extending current screening guidelines to include testing to identify those with high polygenic AAA risk, once the cost of genotyping becomes comparable with that of screening ultrasound, would significantly increase the yield of current screening at reasonable cost.

Large-scale multi-ethnic cohorts offer unprecedented opportunities to elucidate the genetic factors influencing complex traits related to health and disease among minority populations. At the same time, the genetic diversity in these cohorts presents new challenges for analysis and interpretation. We consider the utility of race and/or ethnicity categories in genome-wide association studies (GWASs) of multi-ethnic cohorts. We demonstrate that race/ethnicity information enhances the ability to understand population-specific genetic architecture. To address the practical issue that self-identified racial/ethnic information may be incomplete, we propose a machine learning algorithm that produces a surrogate variable, termed HARE. We use height as a model trait to demonstrate the utility of HARE and ethnicity-specific GWASs.

IMPORTANCE: Electronic health record (EHR) biobanks containing clinical and genomic data on large numbers of individuals have great potential to inform drug discovery. Individuals with interleukin 6 receptor (IL6R) single-nucleotide polymorphisms (SNPs) who are not receiving IL6R blocking therapy have biomarker profiles similar to those treated with IL6R blockers. This gene–drug pair provides an example to test whether associations of IL6R SNPs with a broad range of phenotypes can inform which diseases may benefit from treatment with IL6R blockade. OBJECTIVE: To determine whether screening for clinical associations with the IL6R SNP in a phenome-wide association study (PheWAS) using EHR biobank data can identify drug effects from IL6R clinical trials. DESIGN, SETTING, AND PARTICIPANTS: Diagnosis codes and routine laboratory measurements were extracted from the VA Million Veteran Program (MVP); diagnosis codes were mapped to phenotype groups using published PheWAS methods. A PheWAS was performed by fitting logistic regression models for testing associations of the IL6R SNPs with 1342 phenotype groups and by fitting linear regression models for testing associations of the IL6R SNP with 26 routine laboratory measurements. Significance was reported using a false discovery rate of 0.05 or less. Findings were replicated in 2 independent cohorts using UK Biobank and Vanderbilt University Biobank data. The Million Veteran Program included 332 799 US veterans; the UK Biobank, 408 455 individuals from the general population of the United Kingdom; and the Vanderbilt University Biobank, 13 835 patients from a tertiary care center. EXPOSURES: IL6R SNPs (rs2228145; rs4129267). MAIN OUTCOMES AND MEASURES: Phenotypes defined by International Classification of Diseases, Ninth Revision codes. RESULTS: Of the 332 799 veterans included in the main cohort, 305 228 (91.7%) were men, and the mean (SD) age was 66.1 (13.6) years. The IL6R SNP was most strongly associated with a reduced risk of aortic aneurysm phenotypes (odds ratio, 0.87-0.90; 95% CI, 0.84-0.93) in the MVP. We observed known off-target effects of IL6R blockade from clinical trials (eg, higher hemoglobin level). The reduced risk for aortic aneurysms among those with the IL6R SNP in the MVP was replicated in the Vanderbilt University Biobank, and the reduced risk for coronary heart disease was replicated in the UK Biobank. CONCLUSIONS AND RELEVANCE: In this proof-of-concept study, we demonstrated application of the PheWAS using large EHR biobanks to inform drug effects. The findings of an association of the IL6R SNP with reduced risk for aortic aneurysms correspond with the newest indication for IL6R blockade, giant cell arteritis, of which a major complication is aortic aneurysm.

Background The Department of Veterans Affairs Million Veteran Program (MVP) is the largest ongoing cohort program of its kind, with 654,903 enrollees as of June 2018. The objectives of this study were to examine gender differences in the MVP cohort with respect to response and enrollment rates; demographic, health, and health care characteristics; and prevalence of self-reported health conditions. Methods The MVP Baseline Survey was completed by 415,694 veterans (8% women), providing self-report measures of demographic characteristics, health status, and medical history. Results Relative to men, women demonstrated a higher positive responder rate (23.0% vs. 16.0%), slightly higher enrollment rate (13.5% vs. 12.9%), and, among enrollees, a lower survey completion rate (59.7% vs. 63.8%). Women were younger, more racially diverse, had higher educational attainment, and were less likely to be married or cohabitating with a partner than men. Women were more likely to report good to excellent health status but poorer physical fitness, and less likely to report lifetime smoking and drinking than men. Compared with men, women veterans showed an increased prevalence of musculoskeletal conditions, thyroid problems, gastrointestinal conditions, migraine headaches, and mental health disorders, as well as a decreased prevalence of gout, cardiovascular diseases, high cholesterol, diabetes, and hearing problems. Conclusions These results revealed some substantial gender differences in the research participation rates, demographic profile, health characteristics, and prevalence of health conditions for veterans in the MVP cohort. Findings highlight the need for tailoring recruitment efforts to ensure representation of the increasing women veteran population receiving care through the Veterans Health Administration.

Introduction This team-based learning (TBL) module is a self-contained unit covering the basic and clinical sciences of sleep disorders. It also introduces the topics of electroencephalography (EEG) and epilepsy. Methods The module includes a comprehensive and image-rich reading assignment with a glossary. It is presented to our students near the conclusion of their second year of medical school, as part of our integrated neurosciences course. This TBL module is part of a nine-credit integrated neurosciences course and counts for 1% of the course grade. Results We have presented this TBL to nearly 200 second-year medical students over the last 2 years. The mean individual readiness assurance test score was 89% (range 40-100%) and mean group readiness assurance test score was 99.8% (range 96-100%). Discussion The most important lesson we learned while developing this TBL module was that students really benefited from and appreciated a comprehensive reading assignment from a single source. These can be very difficult to find for second-year medical students. Second-year medical students are expected to know a great deal of basic sciences.

X-linked Charcot-Marie-Tooth disease (CMTX) is the second most common form of Charcot-Marie-Tooth disease. Variable histopathological and nerve conduction velocity (NCV) results have suggested either a primary demyelinating or axonal polyneuropathy. We identified five individuals across three generations in a family with CMTX associated with a mutation in the gene coding for connexin 32. All individuals were studied by clinical neurological examination, DNA analysis, and nerve conduction studies. The proband (1174/KD) also underwent a sural nerve biopsy. As expected, all the affected males were more clinically affected than the females. All affected males and obligate female carriers exhibited some electrophysiological characteristics of demyelination. However, striking heterogeneity of nerve conduction velocities was seen. This family shows that CMTX is a heterogeneous and distinctly nonuniform demyelinating polyneuropathy, the severity of which varies with sex and age. Such electrophysiological variability is unique among hereditary neuropathies.

Chronic axonal polyneuropathies are very frequently encountered by physicians. It is important to take a systematic approach when evaluating these patients. In this chapter we present such an approach. We present the diagnostic recommendations based on previously published evidence-based reviews and guidelines.

Accurate evaluation of peripheral nerve injury is crucial in planning treatment. Understanding the classification of Sunderland and Seddon helps in predicting prognosis. This chapter discusses the basic reactions to peripheral nerve injury, classification of peripheral nerve injury, and the preoperative, intraoperative, and postoperative electrodiagnostic evaluation of nerve injury. It also covers the novel methods utilized in the treatment of peripheral nerve injuries with all potential therapeutic interventions.

Chronic axonal polyneuropathies are very frequently encountered by physicians. It is important to take a systematic approach when evaluating these patients. In this chapter we present such an approach. We present the diagnostic recommendations based on previously published evidence-based reviews and guidelines.

Neuralgic amyotrophy has a broad variety of clinical manifestations. Although it was initially thought to be a plexopathy, its diverse presentation can include isolated sensory nerves or even cranial nerves. Although neuralgic amyotrophy is usually a benign condition with a good recovery, pain can be a disabling feature. NSAIDs and short-term narcotics are appropriate treatments. There is lack of evidence whether the use of corticosteroids has an impact on the duration of the disease or the neuropathic pain. However, given the few adverse effects in a selective population and low cost, short-term steroids can be an option for the treatment of these patients.

One of the fundamental principles of electrodiagnostic medicine is the assessment of the peripheral nervous system's ability to conduct an electrical impulse. Nerve conduction studies (NCs) and needle electromyography (EMG), are commonly referred to as electrodiagnostic or EMG studies. The primary goals of the EMG study are to localize the lesion, characterize the underlying nerve pathophysiology, quantitate the severity of the lesion, and assess the temporal course of the disorder. Weakness can be secondary to a lesion in the upper motor neuron pool or within the lower motor neuron pool. Some patients may, in the course of their rehabilitation, develop a pattern of proximal weakness. This weakness usually begins in the lower extremities and then progresses to involve the proximal arms. Surface EMG (SEMG) can provide a simple, noninvasive method to assess the activation of muscles involved in performing specific tasks.

Krabbe disease is a progressive leukodystrophy that results in demyelination in the central and peripheral nervous systems in humans. It has been described in a number of mammalian species including the rhesus monkey. We performed serial nerve conduction studies beginning within the first 2 months of life in four homozygous, two heterozygous, and two normal rhesus monkeys (Macaca mulatta) to characterize the peripheral neuropathy. Mean conduction velocities of the median, ulnar, and tibial nerves were significantly slower in the affected than unaffected monkeys at all ages (P < 0.0001). The conduction velocity differences became more apparent between the affected and unaffected as the monkeys aged. When compared to the unaffected monkeys, the serial conduction velocities suggested occurrence of dysmyelination followed by demyelination in the affected monkeys. These observations provide further insight into the disease process and suggest an early window of opportunity for treating Krabbe disease.

Publisher Summary This chapter presents a study on cranial nerves and brain stem, and idiopathic (bell's) facial palsy. The chapter states that facial nerve compromise the most commonly encountered cranial neuropathy. Precisely, the idiopathic or Bell's palsy form is the most common cause of infranuclear seventh nerve dysfunction. Idiopathic facial nerve paralysis (IFNP) is defined as a facial paralysis of unknown origin; thus it is a diagnosis of exclusion. Most patients with Bell's palsy display a rather sudden onset of unilateral partial or complete facial muscle paralysis with no suggestion of central nervous system or posterior fossa/ear disease. Associated complaints in decreasing order of frequency include numbness or pain in front or behind the ear, alterations in taste, hyperacusis, facial numbness ipsilateral to the side of weakness and decreased tearing in the affected eye. Physical examination reveal some degree of weakness involving muscles of facial expression and platysmal. Facial muscles pull to the opposite side on smiling. Facial muscles pull to the opposite side on smiling. Saliva and food may collect on the paralyzed side, and on attempting to close the eye the eyeball may be diverted upward and inward, which is known as the Bell's phenomenon. The chapter discusses clinical aspects, natural course, and principles of therapy. The discussion on practical management includes prednisone/acyclovir, eyelid surgery, surgical decompression of the nerve, and others.