Regulatory variants in TCF7L2 are associated with thoracic aortic aneurysm.

Thoracic aortic aneurysm (TAA) is characterized by dilation of the aortic root or ascending/descending aorta. TAA is a heritable disease that can be potentially life threatening. While 10%-20% of TAA cases are caused by rare, pathogenic variants in single genes, the origin of the majority of TAA cases remains unknown. A previous study implicated common variants in FBN1 with TAA disease risk. Here, we report a genome-wide scan of 1,351 TAA-affected individuals and 18,295 control individuals from the Cardiovascular Health Improvement Project and Michigan Genomics Initiative at the University of Michigan. We identified a genome-wide significant association with TAA for variants within the third intron of TCF7L2 following replication with meta-analysis of four additional independent cohorts. Common variants in this locus are the strongest known genetic risk factor for type 2 diabetes. Although evidence indicates the presence of different causal variants for TAA and type 2 diabetes at this locus, we observed an opposite direction of effect. The genetic association for TAA colocalizes with an aortic eQTL of TCF7L2, suggesting a functional relationship. These analyses predict an association of higher expression of TCF7L2 with TAA disease risk. In vitro, we show that upregulation of TCF7L2 is associated with BCL2 repression promoting vascular smooth muscle cell apoptosis, a key driver of TAA disease.

Electrocochleography Results in Patients With Bilateral Vestibular Paresis and Sound- or Pressure-Induced Horizontal Nystagmus.

OBJECTIVE: To describe the electrocochleography (ECochG) findings in patients with bilateral vestibular paresis and sound- and/or pressure-induced horizontal nystagmus. DESIGN: Retrospective case series. SETTING: Tertiary care center. PATIENTS: Three adult patients with bilateral vestibular paresis and sound- and/or pressure-induced horizontal nystagmus were evaluated from 2012 to 2016. MAIN OUTCOME MEASURE: All patients underwent ECochG, vestibular evoked myogenic potential (VEMP) testing, bithermal caloric testing, rotary chair testing, audiometric testing, and temporal bone computed tomography (CT). For ECochG, the summating potential (SP) to action potential (AP) ratio was determined. RESULTS: All patients had normal temporal bone CT, reduced caloric responses bilaterally, decreased gain on rotary chair, and abnormal ECochG. For two subjects, the SP/AP was elevated bilaterally. One subject had unilateral SP/AP elevation. Cervical VEMPs were present in all subjects, but at reduced thresholds in two subjects. CONCLUSION: SP/AP elevation was found in all three patients with the syndrome of bilateral vestibular paresis and/or sound- or pressure-induced horizontal nystagmus. As the etiology of this syndrome remains unclear, understanding the basis for abnormal ECochG may shed insight into the pathophysiology of this condition.

"My Plate is Full": Reasons for Declining a Genetic Evaluation of Hearing Loss.

The aim of this study was to obtain patient and parent perspectives on genetic evaluation of hearing loss, in order to identify motivators, expectations, and barriers. Three focus groups were conducted following a semi-structured discussion guide, led by an independent moderator. Participants were hearing parents of children with permanent hearing loss or deaf adults. Qualitative content analysis was used to develop a codebook and identify major themes and subthemes. Participant views were compared to national guidelines. The 28 participants comprised 23 parents representing 21 unique families and 5 deaf adults. 13/21 families and 0/5 adults reported comorbidities, 4/21 families and 3/5 adults had a positive family history, and 12/21 families versus 0/5 adults had utilized genetics services. A common theme among adults and parents was a curiosity as to the cause of hearing loss. Parents were motivated to detect comorbidities and optimize care for hearing loss. Some parents felt overwhelmed by the hearing loss and unprepared to pursue early genetic evaluation as recommended in guidelines. Several reported positive experiences following genetics consultation, while others reported unease and unmet expectations. Notably, both parents and adults expressed ambivalence regarding the desire for genetic knowledge. Financial concerns and difficulties obtaining a referral were cited as extrinsic barriers. For parents of children with hearing loss, both the presence of comorbidities and a positive family history were drivers of genetics consultation and/or genetic testing. We identified educational opportunities for both patients and providers that would improve informed decision-making and increase access to genetic services. Consideration of the patient/family perspective and their decision-making processes, along with flexibility in the approach to genetics evaluation and its timing, will optimize both the development and implementation of guidelines.

Superior Canal Dehiscence Syndrome Affecting 3 Families.

Importance: Superior canal dehiscence syndrome (SCDS) is an increasingly recognized cause of hearing loss and vestibular symptoms, but the etiology of this condition remains unknown. Objective: To describe 7 cases of SCDS across 3 families. Design, Setting, and Participants: This retrospective case series included 7 patients from 3 different families treated at a neurotology clinic at a tertiary academic medical center from 2010 to 2014. Patients were referred by other otolaryngologists or were self-referred. Each patient demonstrated unilateral or bilateral SCDS or near dehiscence. Interventions: Clinical evaluation involved body mass index calculation, audiometry, cervical vestibular evoked myogenic potential testing, electrocochleography, and multiplanar computed tomographic (CT) scan of the temporal bones. Zygosity testing was performed on twin siblings. Main Outcomes and Measures: The diagnosis of SCDS was made if bone was absent over the superior semicircular canal on 2 consecutive CT images, in addition to 1 physiologic sign consistent with labyrinthine dehiscence. Near dehiscence was defined as absent bone on only 1 CT image but with symptoms and at least 1 physiologic sign of labyrinthine dehiscence. Results: A total of 7 patients (5 female and 2 male; age range, 8-49 years) from 3 families underwent evaluation. Family A consisted of 3 adult first-degree relatives, of whom 2 were diagnosed with SCDS and 1 with near dehiscence. Family B included a mother and her child, both of whom were diagnosed with unilateral SCDS. Family C consisted of adult monozygotic twins, each of whom was diagnosed with unilateral SCDS. For all cases, dehiscence was located at the arcuate eminence. Obesity alone did not explain the occurrence of SCDS because 5 of the 7 cases had a body mass index (calculated as weight in kilograms divided by height in meters squared) less than 30.0. Conclusions and Relevance: Superior canal dehiscence syndrome is a rare, often unrecognized condition. This report of 3 multiplex families with SCDS provides evidence in support of a potential genetic contribution to the etiology. Symptomatic first-degree relatives of patients diagnosed with SCDS should be offered evaluation to improve detection of this disorder.