Unprecedented coexistence of Dent's disease type 1 and Wilson's disease in a two-year-old Chinese boy: implications for precision medicine.

BACKGROUND: The concurrent diagnosis of Dent’s disease type 1 (DD1) and Wilson’s disease (WD) in a single individual has not been previously documented. The co-occurrence of these two distinct autosomal recessive and X-linked disorders poses significant diagnostic challenges. CASE PRESENTATION: We describe a two-year-old Chinese boy who presented with isolated low-molecular-weight proteinuria (LMWP) and mildly elevated liver enzymes. Genetic analysis revealed a hemizygous variant in the CLCN5 gene (c.1756C>T, p.R586W) and compound heterozygous variants in the ATP7B gene (c.994G>T, p.Glu332* and c.4014T>A, p.Ile1338=), confirming the diagnoses of DD1 and WD, respectively. The diagnosis was supported by characteristic biochemical findings, including markedly reduced serum caeruloplasmin and elevated 24-hour urinary copper excretion, culminating in a Leipzig score of 7. CONCLUSION: This case represents the first reported instance of concomitant DD1 and WD. It underscores the critical role of comprehensive genetic testing in elucidating complex pediatric phenotypes involving multi-system presentations and highlights the practical implications for precision medicine in guiding diagnosis and therapeutic strategy, particularly in avoiding potentially nephrotoxic treatments like D-penicillamine. CLINICAL TRIAL REGISTRATION: Not applicable. This article is a case report and does not report results of a clinical trial.