Optimized testing strategy for the diagnosis of GAA-FGF14 ataxia/spinocerebellar ataxia 27B.

Dominantly inherited GAA repeat expansions in FGF14 are a common cause of spinocerebellar ataxia (GAA-FGF14 ataxia; spinocerebellar ataxia 27B). Molecular confirmation of FGF14 GAA repeat expansions has thus far mostly relied on long-read sequencing, a technology that is not yet widely available in clinical laboratories. We developed and validated a strategy to detect FGF14 GAA repeat expansions using long-range PCR, bidirectional repeat-primed PCRs, and Sanger sequencing. We compared this strategy to targeted nanopore sequencing in a cohort of 22 French Canadian patients and next validated it in a cohort of 53 French index patients with unsolved ataxia. Method comparison showed that capillary electrophoresis of long-range PCR amplification products significantly underestimated expansion sizes compared to nanopore sequencing (slope, 0.87 [95% CI, 0.81 to 0.93]; intercept, 14.58 [95% CI, - 2.48 to 31.12]) and gel electrophoresis (slope, 0.84 [95% CI, 0.78 to 0.97]; intercept, 21.34 [95% CI, - 27.66 to 40.22]). The latter techniques yielded similar size estimates. Following calibration with internal controls, expansion size estimates were similar between capillary electrophoresis and nanopore sequencing (slope: 0.98 [95% CI, 0.92 to 1.04]; intercept: 10.62 [95% CI, - 7.49 to 27.71]), and gel electrophoresis (slope: 0.94 [95% CI, 0.88 to 1.09]; intercept: 18.81 [95% CI, - 41.93 to 39.15]). Diagnosis was accurately confirmed for all 22 French Canadian patients using this strategy. We also identified 9 French patients (9/53; 17%) and 2 of their relatives who carried an FGF14 (GAA)≥250 expansion. This novel strategy reliably detected and sized FGF14 GAA expansions, and compared favorably to long-read sequencing.

Impact of Strategy on Clinical Outcome in Large Vessel Occlusion Stroke Successfully Reperfused: ETIS Registry Results.

BACKGROUND AND PURPOSE: Approximately half of the patients with acute ischemic stroke due to anterior circulation large vessel occlusion do not achieve functional independence despite successful reperfusion. We aimed to determine influence of reperfusion strategy (bridging therapy, intravenous thrombolysis alone, or mechanical thrombectomy alone) on clinical outcomes in this population. METHODS: From ongoing, prospective, multicenter, observational Endovascular Treatment in Ischemic Stroke registry in France, all patients with anterior circulation large vessel occlusion who achieved successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b-3) following reperfusion therapy were included. Primary end point was favorable outcome, defined as 90-day modified Rankin Scale score ≤2. Patient groups were compared using those treated with bridging therapy as reference. Differences in baseline characteristics were reduced after propensity score-matching, with a maximum absolute standardized difference of 14% for occlusion site. RESULTS: Among 1872 patients included, 970 (51.8%) received bridging therapy, 128 (6.8%) received intravenous thrombolysis alone, and the remaining 774 (41.4%) received MT alone. The rate of favorable outcome was comparable between groups. Excellent outcome (90-day modified Rankin Scale score 0-1) was achieved more frequently in the bridging therapy group compared with the MT alone (odds ratio after propensity score-matching, 0.70 [95% CI, 0.50-0.96]). Regarding safety outcomes, hemorrhagic complications were similar between the groups, but 90-day mortality was significantly higher in the MT alone group compared with the bridging therapy group (odds ratio, 1.60 [95% CI, 1.09-2.37]). CONCLUSIONS: This real-world observational study of patients with anterior circulation large vessel occlusion demonstrated a similar rate of favorable outcome following successful reperfusion with different therapeutic strategies. However, our results suggest that bridging therapy compared with MT alone is significantly associated with excellent clinical outcome and lower mortality. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03776877.