ABSTRACT
Objective:To investigate the characteristics of renal disease spectrum in children aged 0-3 years old, and to evaluate the clinical value of renal biopsy in children aged 0-3 years old with renal diseases.Methods:It was a retrospective analysis study. The children aged 0-3 years old with kidney diseases receiving renal biopsy and having complete clinical data in Shanghai Children's Hospital from January 1, 2009 to December 31, 2020 were enrolled. The clinical and pathological data of the children were collected. The spectrum of renal diseases, clinical phenotype, renal pathology, and the relationship between renal pathology/genotype and clinical phenotype were analyzed.Results:A total of 117 children aged 0-3 years old with kidney diseases were enrolled in the study, accounting for 6.5% (117/1 790) of all children (0-18 years old) with renal biopsies during the same period. There were 77 males and 40 females. The age was (2.20±0.51) years old (5-35 months). All cases of renal biopsies in children aged 0-3 years old were successful without serious complications. Nephrotic syndrome was the common clinical phenotype of kidney diseases in children aged 0-3 years old (59.0%, 69/117), followed by hematuria and proteinuria (29.1%, 34/117). Primary glomerular disease (69.2%, 81/117) was the major clinical type of renal diseases, followed by hereditary kidney diseases (29.1%, 34/117), in which Alport syndrome was the main hereditary kidney disease (79.4%, 27/34). Renal pathological types of children aged 0-3 years old were mainly distributed in minimal change disease (30.8%, 36/117), followed by glomerular minor lesion (26.5%, 31/117), mesangial proliferative glomerulonephritis (15.4%, 18/117), and focal segmental glomerulosclerosis (10.3%, 12/117). Among 40 children aged 0-3 years old with hematuria with/without proteinuria, 25 cases were diagnosed as Alport syndrome by abnormal immunofluorescence of type IV collagen in renal tissues. Among the 28 children with kidney diseases who underwent genetic testing, 23 cases had gene mutations, mainly in COL4A5 gene (60.9%, 14/23), among which 4 children had gene mutations in 8 children with refractory nephrotic syndrome. Among the children aged 0-3 years old with clinical manifestations of hematuria, the proportion of gross hematuria in children diagnosed with Alport syndrome (59.3%, 16/27) was significantly higher than that in children without Alport syndrome (20.0%, 3/15, χ2=5.999, P=0.014). Conclusions:Primary glomerular disease is the principal type of kidney diseases in children aged 0-3 years old, followed by hereditary kidney disease. Attention should be paid to children aged 0-3 years old with gross hematuria. Renal biopsy in children aged 0-3 years old is safe and reliable, and it is an essential means for the diagnosis of renal diseases. Renal biopsy combined with gene testing can better understand the etiology of kidney diseases and guide treatment in children aged 0-3 years old.