Ataxia de Friedreich. Avaliação cardiáca de 24 pacientes com diagnóstico clínico e revisão da literatura / Friedreich's ataxia. Cardiac evaluation of 25 patients with clinical diagnosis and literature review

ABSTRACT

OBJECTIVE - Cardiac evaluation (clinical, electrocardiographic and echocardiographic) of 25 Brazilian patients with clinical diagnosis of Friedreich's ataxia (FA) related to the frequency and the size of GAA repeats (unstable expansion of trinucleotide repeats that results in the disease). METHODS - Clinical and cardiac study including electrocardiogram and echocardiogram of all patients and molecular analysis to detect the frequency and the size of GAA expansion, by polymerase chain reaction analysis. RESULTS - Homozygous GAA expansion was detected in 17 patients (68 percent) -- all typical cases. In 8 (32 percent) cases (6 atypical and 2 typical), no GAA expansion was observed, therefore it was not considered Friedreich's ataxia. All patients with GAA expansion (100 percent) had electrocardiographic abnormalities, and only 25 percent of the cases without GAA expansion had some abnormality on this exam. However, only 6 percent of all patients revealed some signals/symptoms suggestive of cardiac involvement. CONCLUSION - A molecular analysis is essential to confirm the diagnosis of Friedreich's ataxia; however, an adequate cardiac evaluation, including an electrocardiogram, was extremely useful to better screening the patients which should perform these molecular analysis: