Becker Muscular Dystrophy and Nephrotic-Range Proteinuria: Chance or True Association?

Aims/Background Improved life expectancy has led to an increased recognition of kidney dysfunction as a common complication in adults with Duchenne muscular dystrophy (DMD). However, data on renal impairment with Becker muscular dystrophy (BMD) especially in pediatric populations, and remains scarce. Case Presentation We present the case of a 5-year-old male with a two-month history of foamy urine. Laboratory investigations revealed nephrotic-range proteinuria and elevated serum creatine kinase (CK) levels. A subsequent muscle biopsy and genetic analysis confirmed the diagnosis of BMD. Results The patient accepted oral deflazacort for two months. Surprisingly, this targeted treatment at BMD not only led to a reduction in CK levels, but also resolved proteinuria during the two-year follow-up. Conclusion This clinical presentation of nephrotic-range proteinuria in pediatric BMD patients is novel and highlights a rare renal manifestation. Chronic kidney impairment in pediatric BMD warrants attention, and the role of kidney biopsy in characterizing DMD/BMD-associated nephropathy should be explored. Given the lifelong and heterogeneous nature of BMD, multicenter study and long-term follow-up are required to better understand the progression, underlying mechanisms, and clinical outcomes of renal complications in these patients.