Organ dysfunction and muscular disability in myotonic dystrophy type 1

Area of Science:

• Neurology
• Genetics
• Cardiology
• Pulmonology
• Ophthalmology

Background:

• Myotonic dystrophy type 1 (DM1) is a multisystemic disorder causing muscle weakness and organ impairment.
• Key affected organs include the eyes, lungs, and heart, impacting patient quality of life.
• Understanding the intercorrelation of these issues and their link to muscular disability is crucial.

Purpose of the Study:

• To analyze the prevalence of eye, lung, and heart disorders in DM1 patients.
• To investigate the intercorrelation among these organ impairments.
• To determine the relationship between these disorders and the severity of muscular disability.

Main Methods:

• 106 DM1 patients underwent medical history review, anthropometric measurements, lung function tests, blood sampling, ECG, echocardiography, ophthalmologic exams, and MIRS assessment.
• Data analyzed included prevalence of obesity, hypertriglyceridemia, diabetes, cataract, restrictive lung disease, and conduction disorders.
• Multivariate analysis identified predictors for organ involvement and evaluated MIRS cutoffs for predicting lung and cardiac issues.

Main Results:

• Prevalence rates: Obesity (25.6%), hypertriglyceridemia (47.6%), diabetes (17.1%), disabling cataract (43.4%), restrictive lung disease (34%), conduction disorders (30.2%).
• Cataract was predicted by age and MIRS; restrictive lung disease by MIRS, CTG repeat expansion, and BMI.
• Conduction disorders were predicted by LVEF, MIRS, and CTG repeat expansion. MIRS was the sole independent predictor for lung and cardiac issues.

Conclusions:

• Muscular disability severity (MIRS) is a strong predictor of ophthalmologic, cardiac, and pulmonary involvement in DM1.
• Significant correlations exist between cataract, restrictive lung disease, and conduction disorders.
• MIRS scores of ≥3 and ≥4 effectively predict lung and cardiac involvement, respectively, guiding clinical attention.