博士 Yuxiang Liu1,2, Prof. Zhonglin Chai1, Dr. Xiaoshuang Zhou2
1MONASH UNIVERSITY, Melbourne, Australia, 2Shanxi Provincial People's Hospital, Taiyuan, Chna
Biography:
Dr. Liu Yuxiang has dedicated a significant portion of his professional career to the study of renal diseases, both from a clinical and fundamental research perspective. From a clinical perspective, the subject has accrued four years of experience in the field of nephrology. His research has focused on acute kidney injury, hemodialysis, and diabetic nephropathy, areas in which he has conducted in-depth studies. From a research perspective, he offers insightful observations on the mechanisms and therapeutic interventions associated with diabetic nephropathy and the use of stem cell therapy for acute kidney injury.
Imerslund–Gräsbeck syndrome (IGS) is a rare autosomal recessive disorder of vitamin B₁₂ (cobalamin) malabsorption characterized by megaloblastic anaemia and mild, benign proteinuria. We report the case of a 10-year-old Chinese boy who presented with isolated proteinuria as the first and only clinical sign of IGS, without any haematological or neurological abnormalities. The diagnostic workup included extensive laboratory testing, imaging, and ultimately, a renal biopsy, which revealed only mild focal glomerular changes without immune deposits, failing to identify a common cause of proteinuria. Given the persistent non-nephrotic proteinuria and unclear etiology, whole-exome sequencing was performed which uncovered a homozygous CUBN gene mutation (c.5302_5304delATC, p.Ile1768del), confirming the diagnosis of IGS type 1. This CUBN mutation, (affecting the cubilin receptor) explains the combination of benign tubular proteinuria and subclinical cobalamin malabsorption. The patient’s renal function remained normal, and he was managed conservatively with Bailing Capsules and supportive care, with no progression of proteinuria on follow-up, consistent with the benign prognosis of CUBN-related proteinuria. This case highlights an atypical presentation of IGS in a child – an infrequent occurrence (fewer than ten reported cases in the Chinese population) – and underscores the importance of considering a CUBN gene mutation in children with unexplained isolated proteinuria. Genetic testing was crucial in establishing the diagnosis and guiding appropriate management, preventing misdiagnosis and unnecessary interventions.