Related Experiment Videos
Relation of cardiac abnormalities and CTG-repeat size in myotonic dystrophy
J Finsterer1, E Gharehbaghi-Schnell, C Stöllberger
1Ludwig Boltzmann Institute for Research in Epilepsy and Neuromuscular Disorders, Austria.
Insights
Cardiac involvement in myotonic dystrophy (MD) severity is linked to CTG-repeat size, particularly in younger patients. This study highlights the age-dependent relationship between CTG-repeat expansion and cardiac complications in MD patients.
Area of Science:
- Cardiology
- Genetics
- Neuromuscular Disorders
Background:
- Myotonic dystrophy (MD) is a multisystem disorder with significant cardiac involvement.
- The relationship between the severity of cardiac issues and the size of the CTG-repeat expansion in MD remains unclear.
Purpose of the Study:
- To investigate the correlation between CTG-repeat expansion size and the severity of cardiac involvement in patients with myotonic dystrophy.
- To determine if CTG-repeat size influences specific cardiac parameters and overall cardiac involvement score.
Main Methods:
- Prospective, observational study of 21 MD patients (8 women, 13 men; ages 11-88).
- Comprehensive cardiologic evaluation including ECG, echocardiography, and 24-h Holter monitoring.
- Assessment of cardiac involvement using a standardized scoring system and determination of CTG-repeat size from blood leukocytes.
Main Results:
- No statistically significant correlation was found between CTG-repeat size and most cardiac parameters (e.g., heart rate, PQ-interval, QTc-interval, fractional shortening).
- Cardiac involvement score showed a non-significant positive correlation (r=0.09, p>0.05) with CTG-repeat size.
- Cardiac involvement increased with larger CTG-repeat sizes in specific age groups (21-30, 31-40, 41-50 years), with younger patients requiring higher repeat counts for similar involvement.
Conclusions:
- Cardiac involvement in myotonic dystrophy appears to increase with CTG-repeat size, with this relationship being age-dependent.
- While direct correlations with specific ECG and echocardiographic parameters were not significant, the overall trend suggests a link between repeat expansion and cardiac severity, especially when considering age.
- Further research with larger cohorts may elucidate the precise mechanisms and clinical implications of CTG-repeat size on cardiac function in MD.
Abstract:
It is unclear if the severity of cardiac involvement in patients with myotonic dystrophy (MD) is related to the size of the CTG-repeat expansion. This open, uncontrolled, observational, prospective study aimed to find out if there is a relation between the severity of cardiac involvement in MD and the CTG-repeat size. In 21 patients with MD, (8 women, 13 men, aged 11-88 years) a detailed cardiologic examination, including history, clinical examination, electrocardiography (ECG), transthoracic echocardiography and ambulatory 24-h ECG, was carried out and cardiac involvement was assessed according to a previously described scoring system. Additionally, the CTG-repeat size was determined from nuclear DNA of blood leukocytes. The correlation between the CTG-repeat size and the mean heart rate, PQ-interval, QTc-interval, fractional shortening, left ventricular enddiastolic diameter, septal thickness, posterior wall thickness, mean heart rate on 24-h ECG and cardiac involvement score was r=0.47, r=0.086, r=0.11, r=-0.27, r=-0.34, r=-0.06, r=-0.12, r=0.16 and r=0.09 (all p>0.05), respectively. In patients 21-30, 31-40 and 41-50 years of age, cardiac involvement increased with increasing CTG-repeat size. In younger patients, the number of CTG-repeats needed to develop a reasonable cardiac involvement was higher than in older patients. Depending on age, cardiac involvement increases with increasing CTG-repeat size obtained from blood leukocytes in patients with MD.