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Published on: May 18, 2013
Noninvasive genetic testing for type IV collagen nephropathy using oral mucosa DNA sampling in children with
Jiaojiao Liu1,2, Dayin Zhou1,2, Xiaowen Wang3
1Department of Nephrology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China.
Insights
Genetic testing for type IV collagen genes (COL4A3/A4/A5) is effective in diagnosing children with persistent hematuria. This noninvasive approach identifies genetic variants linked to kidney disease, enabling early monitoring and management.
Area of Science:
- Nephrology
- Genetics
- Pediatrics
Background:
- Persistent hematuria in children is a common condition and a potential indicator of chronic kidney disease.
- Type IV collagen-related nephropathies, often presenting as isolated hematuria, necessitate early diagnosis for effective management.
- Traditional diagnostic methods like kidney biopsy and whole exome sequencing are invasive and costly, limiting their use in isolated hematuria cases.
Purpose of the Study:
- To evaluate the utility of noninvasive genetic testing for diagnosing type IV collagen-related nephropathy in children with hematuria.
- To determine the prevalence of pathogenic variants in COL4A3/A4/A5 genes in a pediatric cohort presenting with hematuria.
Main Methods:
- Utilized noninvasive oral mucosa sampling for DNA isolation.
- Developed a genetic testing panel targeting three key type IV collagen nephropathy genes (COL4A3/A4/A5).
- Enrolled pediatric patients with persistent hematuria, excluding those with significant proteinuria or renal insufficiency.
Main Results:
- Identified genetic variants in COL4A3/A4/A5 genes in 33.0% (37/112) of the studied children.
- Pathogenic/likely pathogenic variants explaining hematuria were found in 15.2% (17/112) of patients.
- A higher detection rate of COL4A3/A4/A5 variants was observed in patients with a positive family history, severe hematuria, or microalbuminuria.
Conclusions:
- Noninvasive genetic testing for COL4A genes is a valuable tool for diagnosing type IV collagen-related nephropathy in children with hematuria.
- The study highlights the significant prevalence of COL4A gene variants in this pediatric population.
- Findings underscore the need for close monitoring and long-term follow-up for pediatric patients diagnosed with COL4A gene variants.
Objective:
Hematuria is one of the most common conditions in children, and increase the risk of chronic kidney disease. Persistent hematuria may be the earliest manifestation of type IV collagen-related nephropathy. Early diagnosis is essential for optimized therapy. Due to the invasive nature of kidney biopsy and the high cost of whole exome sequencing, its application in the diagnosis of isolated hematuria is rare. Hence, we performed noninvasive and convenient genetic testing approaches for type IV collagen-related nephropathy.
Methods:
We used noninvasive oral mucosa sampling as an alternative method for DNA isolation for genetic testing and designed a panel targeting three type IV collagen nephropathy-related genes in children with hematuria. Children with persistent hematuria unaccompanied by clinically significant proteinuria or renal insufficiency who underwent genetic testing using a hematuria panel were enrolled.
Results:
Thirty-seven of 112 (33.0%) patients were found to have a genetic variant in COL4A3/A4/A5. Pathogenic/likely pathogenic COL4A3/A4/A5 variants were identified in 17 of the 112 patients analyzed (15.2%), which were considered to explain their hematuria manifestations. In addition, variants of unknown significance (VUSs) were found in 17.8% (20/112) of patients. Furthermore, we observed a much greater COL4A3/A4/A5 variant detection rate in patients with a positive family history or more severe hematuria (RBC ≥ 20/HP) or with coexisting microalbuminuria (59.2% vs. 12.7%, p < 0.001; 64.0% vs. 24.1%, p < 0.001; 66.7% vs. 30.1%, p = 0.025).
Conclusions:
We present the high prevalence of variants in COL4A genes in a multicenter pediatric cohort with hematuria, which requires close monitoring and long-term follow-up.
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