2024 American Academy of Neurology Abstract Website

Objective:

To characterize troponin values in Friedreich ataxia patients and establish correlation with phenotypic features including age, sex, age of onset and GAA1 repeat length.

Background:

Friedreich Ataxia (FA), a progressive neurodegenerative disorder, caused by homozygous Guanine-Adenine-Adenine (GAA) trinucleotide expansion in the frataxin gene is the most common inherited ataxia. Hypertrophic cardiomyopathy is common with premature mortality occurring due to cardiac failure or supraventricular arrhythmia. Elevated cardiac troponin I has been identified as a baseline characteristic in asymptomatic FA patients. While troponin can be a marker of acute myocardial infarction, the significance of its elevation in FA is incompletely understood.

Design/Methods:

We identified 936 troponin values collected between 9/28/2010 to 10/05/2023 in FA patients. Data collected included age of the patients, age of onset, sex, numerical troponin value, GAA1 (shorter allele) repeat length, provoked (symptoms at time of draw) vs unprovoked status of values. Data was analyzed through correlations and multiple regressions using STATA 15.

Results:

Mean age was 21.7 ± 12.4 yrs, representing a younger cohort with an early age of onset (10.6 ± 7.7 yrs). Mean GAA length (678 ± 214) was longer than typical for FA. Troponin values ranged from 0 to 14.68 ng/ml (M 0.35 ± 1.1). 36% of the unprovoked troponin values were abnormal at first visit. The median provoked value of troponin was 25 times higher than median unprovoked value (p<0.0001 by Wilcoxon rank-sum test). Linear regression models showed that troponin value was predicted with high significance (p>0.0001;R-squared 0.10). Age was predictive (p=0.001), sex was marginally predictive (p=0.059) and GAA1 repeat length was not predictive (p=0.634) of abnormal troponin value at first visit.

Conclusions:

Random, unprovoked troponin values are elevated in Friedreich ataxia patients particularly in younger individuals and women, providing an important observation to further understand nature of cardiac disease in FA in order to design future therapies.