The Effect of Genotype Differences on Cardiac Involvement in Cases Diagnosed with Duchenne Muscular Dystrophy.

Aim:  Duchenne muscular dystrophy (DMD) is the most frequently seen muscular disease in childhood. Cardiac involvement is extremely important in terms of morbidity and mortality in these patients. Different studies have shown that mutations occurring in various exons are cardioprotective or increase cardiac involvement in DMD cases. The aim of this study was to examine the effect of genotype differences on cardiac involvement in patients diagnosed with DMD with genetic analysis.

Material and method:  A retrospective analysis of DMD patients followed up in the Muscle Diseases Centre of Health Sciences University Izmir Tepecik Training and Research Hospital was done.

Results:  Evaluation was made of 120 male DMD patients with a mean age of 9.66 ± 5.10 years. According to the genetic analysis results, 76.7% deletions, 15.8% mutations, and 7.5% duplications were determined. Of the mutations determined, 65.8% were between exons 44 and 54, 17.5% between exons 1 and 18, and 9.2% between exons 19 and 43, 5.8% were non-sense mutations, and 1.7% were on exons >54. In the cases determined with cardiac involvement, the mean age of onset was 11.87 ± 3.11 years. When ejection fraction (EF) <56% or fractional shortening (FS) <28% was accepted as systolic dysfunction cardiac effect, 12.5% of the cases were determined with cardiac involvement. Of the cases determined with cardiac effects, 86.7% were aged >10 years. Electrocardiography was evaluated as normal in 54.5%, sinus tachycardia in 24.2%, short PR in 15.2%, and right and left ventricle hypertrophy in 8.1%. No statistically significant difference was determined in mutation types and location according to the age of cardiac involvement. The left ventricle (LV) posterior wall thickness value determined in the exon 44-54 group was higher than in DMD cases with other mutations. Although not statistically significant, an important result was that the LV posterior wall and IVSed values were evaluated to be high.

Conclusion:  The current study results and findings in literature have not found a clear relationship between genotypes and cardiac involvement in DMD cases.