Whole-genome sequencing of patients with rare diseases in a national health system.

Most patients with rare diseases do not receive a molecular diagnosis and the aetiological variants and causative genes for more than half such disorders remain to be discovered1. Here we used whole-genome sequencing (WGS) in a national health system to streamline diagnosis and to discover unknown aetiological variants in the coding and non-coding regions of the genome. We generated WGS data for 13,037 participants, of whom 9,802 had a rare disease, and provided a genetic diagnosis to 1,138 of the 7,065 extensively phenotyped participants. We identified 95 Mendelian associations between genes and rare diseases, of which 11 have been discovered since 2015 and at least 79 are confirmed to be aetiological. By generating WGS data of UK Biobank participants2, we found that rare alleles can explain the presence of some individuals in the tails of a quantitative trait for red blood cells. Finally, we identified four novel non-coding variants that cause disease through the disruption of transcription of ARPC1B, GATA1, LRBA and MPL. Our study demonstrates a synergy by using WGS for diagnosis and aetiological discovery in routine healthcare.

Encephalopathy in a Large Cohort of British Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Patients.

Background and Purpose- Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic form of stroke usually presenting with migraine with aura, lacunar infarcts, and cognitive impairment. Acute encephalopathy is a less recognized presentation of the disease. Methods- Data collected prospectively from 340 consecutively recruited symptomatic patients with diagnosis of CADASIL seen in a British National CADASIL clinic was retrospectively reviewed and original clinical records and imaging obtained. An encephalopathic event was defined as an acute event of an altered state of consciousness in a patient with CADASIL, manifesting with signs of brain dysfunction, which warranted hospital admission in the absence of any other cause. Clinical characteristics, risk factors, and outcome of encephalopathic presentations were studied. Results- A total of 35 of 340 (10.3%) participants had a history of 50 encephalopathic events which was the first hospital presentation of CADASIL in 33 (94.3%) patients. Most commonly reported features during episodes were visual hallucinations (44%), seizures (22%), and focal neurological deficits (60%).Complete recovery within 3 months was reported in 48(96%) episodes. In 62% of episodes, there was a history of migraine or migraine aura directly preceding the encephalopathy. In 2 out of 15 cases where magnetic resonance imaging during episodes was available, unilateral focal cortical swelling was seen. A past history of migraine was independently associated with encephalopathy (odds ratio=12.3 [95% CI, 1.6-93.7]; P=0.015). Conclusions- In up to 10% of CADASIL patients, a reversible encephalopathy is the first presentation leading to diagnosis. The strong association with migraine suggests a shared pathogenesis. Focal cortical swelling may be seen on magnetic resonance imaging during the acute episode.

Near-Infrared 1064 nm Laser Modulates Migratory Dendritic Cells To Augment the Immune Response to Intradermal Influenza Vaccine.

Brief exposure of skin to near-infrared (NIR) laser light has been shown to augment the immune response to intradermal vaccination and thus act as an immunologic adjuvant. Although evidence indicates that the NIR laser adjuvant has the capacity to activate innate subsets including dendritic cells (DCs) in skin as conventional adjuvants do, the precise immunological mechanism by which the NIR laser adjuvant acts is largely unknown. In this study we sought to identify the cellular target of the NIR laser adjuvant by using an established mouse model of intradermal influenza vaccination and examining the alteration of responses resulting from genetic ablation of specific DC populations. We found that a continuous wave (CW) NIR laser adjuvant broadly modulates migratory DC (migDC) populations, specifically increasing and activating the Lang+ and CD11b-Lang- subsets in skin, and that the Ab responses augmented by the CW NIR laser are dependent on DC subsets expressing CCR2 and Langerin. In comparison, a pulsed wave NIR laser adjuvant showed limited effects on the migDC subsets. Our vaccination study demonstrated that the efficacy of the CW NIR laser is significantly better than that of the pulsed wave laser, indicating that the CW NIR laser offers a desirable immunostimulatory microenvironment for migDCs. These results demonstrate the unique ability of the NIR laser adjuvant to selectively target specific migDC populations in skin depending on its parameters, and highlight the importance of optimization of laser parameters for desirable immune protection induced by an NIR laser-adjuvanted vaccine.

Brief Screening of Vascular Cognitive Impairment in Patients With Cerebral Autosomal-Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Without Dementia.

BACKGROUND AND PURPOSE: Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic form of cerebral small vessel disease leading to early-onset stroke and dementia, with younger patients frequently showing subclinical deficits in cognition. At present, there are no targeted cognitive screening measures for this population. However, the Brief Memory and Executive Test (BMET) and the Montreal Cognitive Assessment (MoCA) have shown utility in detecting cognitive impairment in sporadic small vessel disease. This study assesses the BMET and the MoCA as clinical tools for detecting mild cognitive deficits in CADASIL. METHODS: Sixty-six prospectively recruited patients with CADASIL, and 66 matched controls completed the BMET, with a subset of these also completing the MoCA. Receiver operating characteristic curves were calculated to examine the sensitivity and specificity of clinical cutoffs for the detection of vascular cognitive impairment and reduced activities of daily living. RESULTS: Patients with CADASIL showed more cognitive impairment overall and were poorer on both executive/processing and memory indices of the BMET relative to controls. The BMET showed good accuracy in predicting vascular cognitive impairment (85% sensitivity and 84% specificity) and impaired instrumental activities of daily living (92% sensitivity and 77% specificity). The MoCA also showed good predictive validity for vascular cognitive impairment (80% sensitivity and 78% specificity) and instrumental activities of daily living (75% sensitivity and 76% specificity). The most important background predictor of vascular cognitive impairment was a history of stroke. CONCLUSIONS: The results indicate that the BMET and the MoCA are clinically useful and sensitive screening measures for early cognitive impairment in patients with CADASIL.

How common are single gene mutations as a cause for lacunar stroke? A targeted gene panel study.

OBJECTIVES: To determine the frequency of rare and pertinent disease-causing variants in small vessel disease (SVD)-associated genes (such as NOTCH3, HTRA1, COL4A1, COL4A2, FOXC1, TREX1, and GLA) in cerebral SVD, we performed targeted gene sequencing in 950 patients with younger-onset apparently sporadic SVD stroke using a targeted sequencing panel. METHODS: We designed a high-throughput sequencing panel to identify variants in 15 genes (7 known SVD genes, 8 SVD-related disorder genes). The panel was used to screen a population of 950 patients with younger-onset (≤70 years) MRI-confirmed SVD stroke, recruited from stroke centers across the United Kingdom. Variants were filtered according to their frequency in control databases, predicted effect, presence in curated variant lists, and combined annotation dependent depletion scores. Whole genome sequencing and genotyping were performed on a subset of patients to provide a direct comparison of techniques. The frequency of known disease-causing and pertinent variants of uncertain significance was calculated. RESULTS: We identified previously reported variants in 14 patients (8 cysteine-changing NOTCH3 variants in 11 patients, 2 HTRA1 variants in 2 patients, and 1 missense COL4A1 variant in 1 patient). In addition, we identified 29 variants of uncertain significance in 32 patients. CONCLUSION: Rare monogenic variants account for about 1.5% of younger onset lacunar stroke. Most are cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy variants, but the second most common gene affected is HTRA1. A high-throughput sequencing technology platform is an efficient, reliable method to screen for such mutations.

Semiconductor diode laser device adjuvanting intradermal vaccine.

A brief exposure of skin to a low-power, non-tissue damaging laser light has been demonstrated to augment immune responses to intradermal vaccination. Both preclinical and clinical studies show that this approach is simple, effective, safe and well tolerated compared to standard chemical or biological adjuvants. Until now, these laser exposures have been performed using a diode-pumped solid-state laser (DPSSL) devices, which are expensive and require labor-intensive maintenance and special training. Development of an inexpensive, easy-to-use and small device would form an important step in translating this technology toward clinical application. Here we report that we have established a handheld, near-infrared (NIR) laser device using semiconductor diodes emitting either 1061, 1258, or 1301nm light that costs less than $4000, and that this device replicates the adjuvant effect of a DPSSL system in a mouse model of influenza vaccination. Our results also indicate that a broader range of NIR laser wavelengths possess the ability to enhance vaccine immune responses, allowing engineering options for the device design. This small, low-cost device establishes the feasibility of using a laser adjuvant approach for mass-vaccination programs in a clinical setting, opens the door for broader testing of this technology with a variety of vaccines and forms the foundation for development of devices ready for use in the clinic.

Monogenic causes of stroke: now and the future.

Most stroke is multifactorial with multiple polygenic risk factors each conferring small increases in risk interacting with environmental risk factors, but it can also arise from mutations in a single gene. This review covers single-gene disorders which lead to stroke as a major phenotype, with a focus on those which cause cerebral small vessel disease (SVD), an area where there has been significant recent progress with findings that may inform us about the pathogenesis of SVD more broadly. We also discuss the impact that next generation sequencing technology (NGST) is likely to have on clinical practice in this area. The most common form of monogenic SVD is cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, due to the mutations in the NOTCH3 gene. Several other inherited forms of SVD include cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy, retinal vasculopathy with cerebral leukodystrophy, collagen type IV α1 and α2 gene-related arteriopathy and FOXC1 deletion related arteriopathy. These monogenic forms of SVD, with overlapping clinical phenotypes, are beginning to provide insights into how the small arteries in the brain can be damaged and some of the mechanisms identified may also be relevant to more common sporadic SVD. Despite the discovery of these disorders, it is often challenging to clinically and radiologically distinguish between syndromes, while screening multiple genes for causative mutations that can be costly and time-consuming. The rapidly falling cost of NGST may allow quicker diagnosis of these rare causes of SVD, and can also identify previously unknown disease-causing variants.