Abstract
Duchenne's muscular dystrophy (DMD) is a debilitating X-linked recessive disorder of dystrophin gene expression that culminates in the downregulation of dystrophin in cardiac and skeletal muscle. As a result, there is progressive muscle weakness, fibrosis, and atrophy. The skeletal and cardiac muscle degeneration rapidly progresses to the respective loss of ambulation and death from cardiac muscle failure by the second and fourth decades of life. Although muscle degeneration has been demonstrated in utero patients are initially asymptomatic. Therefore, diagnosis is typically delayed until about five years of age when proximal muscle weakness initiates a diagnostic workup that uncovers the disease. We present the rare case of an early diagnosis of DMD. A two-month-old, the only male offspring of a family with three children, was discovered to have hyper-transaminisemia during hospitalization for pneumonia. His preceding medical history was only significant for fever, cough, and rhinorrhea. The pregnancy and birth were uneventful. No abnormalities were detected on the newborn screen. Physical examination was reassuring with no peripheral stigmata of liver disease. Ultrasonographic assessments, metabolic assays, and infectious disease markers were within normal limits. Creatine kinase (CK) was markedly elevated and our patient was subsequently confirmed to be positive for a pathogenic hemizygous variant of the DMD gene. Reliance on an abnormal clinical presentation to trigger diagnostic workup for DMD has led to delays in the diagnosis of this genetic disorder. Incorporating CK analysis into newborn screening panels may enable more children to commence workup in infancy rather than at the current average age of 4.9 years. Early diagnosis is of value in the early initiation of monitoring, anticipatory guidance, and availing families' opportunities to harness current trends of care.