Investigation of the Genetic Determinants of Telangiectasia and Solid Organ Arteriovenous Malformation Formation in Hereditary Hemorrhagic Telangiectasia (HHT).

Telangiectases and arteriovenous malformations (AVMs) are the characteristic lesions of Hereditary Hemorrhagic Telangiectasia (HHT). Somatic second-hit loss-of-function variations in the HHT causative genes, ENG and ACVRL1, have been described in dermal telangiectasias. It is unclear if somatic second-hit mutations also cause the formation of AVMs and nasal telangiectasias in HHT. To investigate the genetic mechanism of AVM formation in HHT, we evaluated multiple affected tissues from fourteen individuals. DNA was extracted from fresh/frozen tissue of 15 nasal telangiectasia, 4 dermal telangiectasia, and 9 normal control tissue biopsies, from nine unrelated individuals with HHT. DNA from six formalin-fixed paraffin-embedded (FFPE) AVM tissues (brain, lung, liver, and gallbladder) from five individuals was evaluated. A 736 vascular malformation and cancer gene next-generation sequencing (NGS) panel was used to evaluate these tissues down to 1% somatic mosaicism. Somatic second-hit mutations were identified in three in four AVM biopsies (75%) or half of the FFPE (50%) samples, including the loss of heterozygosity in ENG in one brain AVM sample, in which the germline mutation occurred in a different allele than a nearby somatic mutation (both are loss-of-function mutations). Eight of nine (88.9%) patients in whom telangiectasia tissues were evaluated had a somatic mutation ranging from 0.68 to 1.96% in the same gene with the germline mutation. Six of fifteen (40%) nasal and two of four (50%) dermal telangiectasia had a detectable somatic second hit. Additional low-level somatic mutations in other genes were identified in several telangiectasias. This is the first report that nasal telangiectasias and solid organ AVMs in HHT are caused by very-low-level somatic biallelic second-hit mutations.

Using nanopore sequencing to identify bacterial infection in joint replacements: a preliminary study.

This project investigates if third-generation genomic sequencing can be used to identify the species of bacteria causing prosthetic joint infections (PJIs) at the time of revision surgery. Samples of prosthetic fluid were taken during revision surgery from patients with known PJIs. Samples from revision surgeries from non-infected patients acted as negative controls. Genomic sequencing was performed using the MinION device and the rapid sequencing kit from Oxford Nanopore Technologies. Bioinformatic analysis pipelines to identify bacteria included Basic Local Alignment Search Tool, Kraken2 and MinION Detection Software, and the results were compared with standard of care microbiological cultures. Furthermore, there was an attempt to predict antibiotic resistance using computational tools including ResFinder, AMRFinderPlus and Comprehensive Antibiotic Resistance Database. Bacteria identified using microbiological cultures were successfully identified using bioinformatic analysis pipelines. Nanopore sequencing and genomic classification could be completed in the time it takes to perform joint revision surgery (2-3 h). Genomic sequencing in this study was not able to predict antibiotic resistance in this time frame, this is thought to be due to a short-read length and low read depth. It can be concluded that genomic sequencing can be useful to identify bacterial species in infected joint replacements. However, further work is required to investigate if it can be used to predict antibiotic resistance within clinically relevant timeframes.

Prevalence, Demographic, and Clinical Factors Associated With Cognitive Dysfunction in Patients With Neuromyelitis Optica Spectrum Disorder.

BACKGROUND AND OBJECTIVES: Neuromyelitis optica spectrum disorder (NMOSD) is a chronic CNS demyelinating autoimmune disorder targeting the astrocyte antigen aquaporin-4 (AQP4), typically presenting with optic neuritis, transverse myelitis, and brain syndromes. Cognitive dysfunction (CD) in NMOSD is under-recognized and poorly understood. The purpose of this study was to evaluate the prevalence and clinical variables associated with CD in NMOSD. METHODS: This observational retrospective study with longitudinal follow-up describes a clinical cohort seen in the Collaborative International Research in Clinical and Longitudinal Experience Study in NMOSD. Serial Montreal Cognitive Assessments (MoCAs) were performed upon enrollment and at 6-month intervals to evaluate longitudinal cognitive function relative to demographic and disease-related factors. We used 2-tailed t test, analysis of variance, the χ2 test, linear regression for univariable and adjusted analyses and simultaneous linear regression and mixed-effects model for multivariable analyses. RESULTS: Thirty-four percent (75/219) of patients met criteria for CD (MoCA <26); 29% (64/219) showed mild dysfunction (MoCA 20-26/30), and 5% (11/219) showed moderate (MoCA <20/30) dysfunction. Patients with less neurologic disability and lower pain scores had higher MoCA scores (95% CI 0.24-0.65 and 95% CI 0.09-0.42, respectively). Patients with at least high school education scored higher on the MoCA (95% CI 2.2-5). When comparing patients dichotomized for CD, patients never on rituximab scored higher than patients only treated with rituximab (p < 0.029). There was no significant association between annualized relapse rate, age, sex, disease duration, AQP4 serostatus or brain lesions, and CD. CD was more pronounced among Black than White patients (95% CI -2.7 to -0.7). Multivariable analysis of serial MoCA did not indicate change (p = 0.715). Descriptive analysis of serial MoCA showed 30% (45/150) of patients with worsening MoCA performance had impaired language and verbal recall. DISCUSSION: To our knowledge, this is the largest study of diverse cohort to investigate CD in patients with NMOSD. Our findings demonstrate 34% of patients with NMOSD experience mild-to-moderate CD, while 30% of patients demonstrated decline on serial testing. The substantial prevalence of CD in this pilot report highlights the need for improved and validated screening tools and comprehensive measures to investigate CD in NMOSD.