McCormack, Shana Erin

Background: Cardiac disease is the leading cause of premature mortality in Friedreich Ataxia (FA). However, validated prognostic indicators or early imaging biomarkers that can reliably predict cardiac events are lacking. To address this gap, we created a multicenter FA cardiac registry to characterize disease progression and identify early echocardiographic (echo) predictors of major adverse cardiac events (MACE). Methods: FA subjects from 6 North American centers with at least two echos performed ≥5 years apart were included. Demographics, FA-specific disease characteristics, and MACE (a composite of death, heart failure hospitalization, aborted sudden cardiac death, and/or life-threatening arrhythmia) were abstracted. Digital echo images were re-read at a centralized core lab. Paired T tests were utilized for comparison of the normally distributed first and second echo parameters, and logistic regression models were utilized to evaluate for predictors of MACE. Results: Of 115 subjects, 52 (45%) were female. Mean age at diagnosis was 10 ± 3 years, median GAA1 repeat length (a marker of genetic severity) was 700 (range 66–1200), and median age at first analyzed echo was 12 years (range 4-36). MACE occurred in 35 (30%) of the cohort. Serial echocardiograms demonstrated progressive worsening of multiple cardiac parameters over time, including markers of ventricular thickness and hypertrophy, chamber size, systolic function, and novel markers of atrial and ventricular strain (Table 1). On univariate analysis, several markers of hypertrophy and systolic function from the earliest analyzed echo predicted MACE. However, after adjusting for age of diagnosis, GAA1 repeat length, and collinearity among variables, only posterior wall thickness in diastole (PWTd) remained an independent predictor of MACE (odds ratio 1.8 per mm increase, 95% CI 1.1–3.3, p = 0.028). Conclusions: This multicenter FA registry identifies early posterior wall thickness as a significant and independent predictor of major adverse cardiac events in FA. Each millimeter increase in PWTd on early echo is associated with nearly double the odds of MACE. This commonly acquired parameter is often overlooked and may serve as a powerful early marker of cardiac risk. Further investigation of PWTd as a potential surrogate endpoint for therapeutic trials in FA is warranted.

OBJECTIVELatent autoimmune diabetes in adults (LADA) shares clinical features with both type 1 and type 2 diabetes; however, there is ongoing debate regarding the precise definition of LADA. Understanding its genetic basis is one potential strategy to gain insight into appropriate classification of this diabetes subtype.RESEARCH DESIGN AND METHODSWe performed the first genome-wide association study of LADA in case subjects of European ancestry versus population control subjects (n = 2,634 vs. 5,947) and compared against both case subjects with type 1 diabetes (n = 2,454 vs. 968) and type 2 diabetes (n = 2,779 vs. 10,396).RESULTSThe leading genetic signals were principally shared with type 1 diabetes, although we observed positive genetic correlations genome-wide with both type 1 and type 2 diabetes. Additionally, we observed a novel independent signal at the known type 1 diabetes locus harboring PFKFB3, encoding a regulator of glycolysis and insulin signaling in type 2 diabetes and inflammation and autophagy in autoimmune disease, as well as an attenuation of key type 1–associated HLA haplotype frequencies in LADA, suggesting that these are factors that distinguish childhood-onset type 1 diabetes from adult autoimmune diabetes.CONCLUSIONSOur results support the need for further investigations of the genetic factors that distinguish forms of autoimmune diabetes as well as more precise classification strategies.