Early Cardiac Dysfunction in Duchenne Muscular Dystrophy: A Case Report and Literature Update

Abstract

Duchenne Muscular Dystrophy (DMD) is a severe X-linked recessive disorder characterized by progressive muscle degeneration due to dystrophin deficiency. Cardiac involvement, particularly dilated cardiomyopathy, significantly impacts morbidity and mortality, typically manifesting after age 10. This case report presents a rare instance of early-onset cardiac involvement in a 3-year-old male with a confirmed deletion in exon 55 of the dystrophin gene. The patient developed dilated cardiomyopathy at 3 years and 8 months, with progressive left ventricular dysfunction despite early treatment with corticosteroids, ACE inhibitors, and beta-blockers. Genetic mechanisms and genotype-phenotype correlations related to cardiac involvement were reviewed, highlighting emerging therapies such as exon skipping, vamorolone, ifetroban, and rimeporide. Studies indicate that variants in exons 12, 14-17, 31-42, 45, and 48-49 are associated with more severe cardiac impairment. This case emphasizes the need for early, ongoing cardiac assessment and personalized treatment to address disease heterogeneity. While current DMD care standards improve survival, optimizing management through early intervention and novel therapies remains essential. Further research is needed to better understand genotype-phenotype correlations and improve cardiac outcomes for patients with DMD.

Keywords: Duchenne muscular dystrophy; cardiac pathology; dilated cardiomyopathy; dystrophin gene; exon skipping; genotype–phenotype.

Figure 1

Schematic representation of the dystrophin gene (79 exons), highlighting the deletion identified in exon 55 (g.1716784_1716785delTA). This deletion causes a frameshift, leading to a premature termination codon (p.His2688Glnfs*21), resulting in the protein terminating prematurely after 21 amino acids.

Figure 2

Echocardiography—evaluation of EF 56.69% by the Teichholz method.

Figure 3

Cardiac ultrasound, incidence 4 chambers peak systolic (Sa) waves were recorded from the lateral mitral annulus (A, 0.8 cm/s), mitral septal annulus (B, 0.7 cm/s)suggestive of mild LV longitudinal dysfunction.

Figure 4

Evolution of NSAA scale scores over time; NSAA = North Star Ambulatory Assessment; y = year/s; m = month/s.

Figure 5

Evolution of 6MWT over time; 6MWT = 6-Minute Walk Test; y = year/s; m = month/s.