Keyword: Children
2 results found.
Congress Abstract
Central Asian Journal of Nephrology, 2(2, Suppl. 1), 2026, cajn_A23, https://doi.org/10.63946/cajn/19533
ABSTRACT:
Introduction and Aim: Atypical hemolytic uremic syndrome (aHUS) is an ultra-rare orphan disease that requires differential diagnosis from other thrombotic microangiopathies (TMAs). The aim of this study was to determine the diagnostic value of ADAMTS13 activity levels, anti‑complement factor H (anti‑CFH) antibody titers, and genetic screening in verifying aHUS subtypes among the pediatric population in Kazakhstan.
Materials and Methods: A retrospective analysis was conducted on 15 children with aHUS (8 girls and 7 boys) from 8 regions of Kazakhstan between 2019 and 2025. The mean age was 7.2 ± 3.8 years. ADAMTS13 activity was measured in 7 patients (46.6%), and anti‑CFH titers were assessed in 10 patients (66.7%). In the remaining patients, these tests were not performed because they had received fresh frozen plasma transfusions prior to testing. Genetic testing was completed for 10 out of 15 children (66.7%); the remaining 5 patients (33.3%) died before testing could be carried out.
Results: In all patients tested (n = 7, 100%), ADAMTS13 activity was >10%, effectively ruling out thrombotic thrombocytopenic purpura (TTP). Autoimmune aHUS associated with anti‑CFH antibodies was diagnosed in 4 out of 10 children (40%), of whom 3 were of Asian descent and 1 was Caucasian. Genetic testing in 10 children revealed pathogenic variants in complement system genes in 2 patients (20%): one child had a CFHR3/CFHR1 deletion, and another had a CFHR1/CFHR4 microdeletion; both exhibited high anti‑CFH titers (up to 11,490 U/mL). Additionally, one child was found to have a clinically insignificant heterozygous autosomal recessive mutation in the ADAMTS13 gene.
The comprehensive laboratory workup allowed for the stratification of aHUS subtypes and personalized therapy. Patients with idiopathic forms received complement‑blocking therapy with eculizumab alone, while children with anti‑CFH antibodies received combined treatment with eculizumab and immunosuppressive agents.
Conclusions: This is the first comprehensive diagnostic data report on pediatric aHUS in Kazakhstan. Genetically determined aHUS was identified in 20% of the cohort. Anti‑CFH–associated aHUS appears to occur more frequently in the Asian population (reported as 50–60% in Indian cohorts by Khandelwal et al.) compared to Caucasians (5–25%). Our findings represent an intermediate frequency between European and Asian populations, which is consistent with the mixed ethnic composition of the Kazakhstani cohort.
Materials and Methods: A retrospective analysis was conducted on 15 children with aHUS (8 girls and 7 boys) from 8 regions of Kazakhstan between 2019 and 2025. The mean age was 7.2 ± 3.8 years. ADAMTS13 activity was measured in 7 patients (46.6%), and anti‑CFH titers were assessed in 10 patients (66.7%). In the remaining patients, these tests were not performed because they had received fresh frozen plasma transfusions prior to testing. Genetic testing was completed for 10 out of 15 children (66.7%); the remaining 5 patients (33.3%) died before testing could be carried out.
Results: In all patients tested (n = 7, 100%), ADAMTS13 activity was >10%, effectively ruling out thrombotic thrombocytopenic purpura (TTP). Autoimmune aHUS associated with anti‑CFH antibodies was diagnosed in 4 out of 10 children (40%), of whom 3 were of Asian descent and 1 was Caucasian. Genetic testing in 10 children revealed pathogenic variants in complement system genes in 2 patients (20%): one child had a CFHR3/CFHR1 deletion, and another had a CFHR1/CFHR4 microdeletion; both exhibited high anti‑CFH titers (up to 11,490 U/mL). Additionally, one child was found to have a clinically insignificant heterozygous autosomal recessive mutation in the ADAMTS13 gene.
The comprehensive laboratory workup allowed for the stratification of aHUS subtypes and personalized therapy. Patients with idiopathic forms received complement‑blocking therapy with eculizumab alone, while children with anti‑CFH antibodies received combined treatment with eculizumab and immunosuppressive agents.
Conclusions: This is the first comprehensive diagnostic data report on pediatric aHUS in Kazakhstan. Genetically determined aHUS was identified in 20% of the cohort. Anti‑CFH–associated aHUS appears to occur more frequently in the Asian population (reported as 50–60% in Indian cohorts by Khandelwal et al.) compared to Caucasians (5–25%). Our findings represent an intermediate frequency between European and Asian populations, which is consistent with the mixed ethnic composition of the Kazakhstani cohort.
Congress Abstract
Central Asian Journal of Nephrology, 2(2, Suppl. 1), 2026, cajn_A37, https://doi.org/10.63946/cajn/19519
ABSTRACT:
Background: Urolithiasis presenting in early childhood requires evaluation for hereditary and metabolic causes, including primary hyperoxaluria. Particular attention is warranted in children with recurrent bilateral nephrolithiasis and a predominantly oxalate stone composition. We report a case of hyperoxaluria in a young child in whom evaluation for primary hyperoxaluria did not confirm an inherited disorder, while further metabolic assessment revealed severe hypomagnesemia.
Case Presentation: A 2-year-10-month-old boy with no family history of urolithiasis first developed nephrolithiasis in June 2025, at approximately 18 months of age. Computed tomography demonstrated bilateral renal calculi and pyelectasis. In July 2025, he underwent left ureteral stent placement, right-sided lumbotomy, and pyelolithotomy. Assessment of kidney function showed an estimated glomerular filtration rate (eGFR) of 75.8 mL/min/1.73 m². In April 2026, nephrolithotomy, left-sided lumbotomy, and pyelolithotomy were performed. Infrared spectroscopy of the extracted stone demonstrated 65% oxalates and 35% phosphates. Metabolic evaluation also confirmed hyperoxaluria.
Given the early age at onset, bilateral stone formation, reduced kidney filtration, and hyperoxaluria, primary hyperoxaluria was considered and molecular genetic testing was performed. Whole-exome sequencing by next-generation sequencing (NGS) detected no pathogenic variants, likely pathogenic variants, or variants of uncertain clinical significance meeting the search criteria for hereditary kidney or metabolic disorders.
In September 2026, severe hypomagnesemia was identified for the first time, with a serum magnesium concentration of 0.18 mmol/L. In view of this finding and the negative genetic evaluation, the hyperoxaluria was considered secondary and associated with magnesium deficiency. Kidney function subsequently improved, with a serum creatinine level of 34.33 µmol/L and an estimated GFR of 92.5 mL/min/1.73 m². Follow-up imaging with ultrasonography and computed tomography demonstrated reduced size of the right kidney and no calculi in the kidneys or urinary collecting system. Management included optimization of fluid intake, dietary recommendations, and magnesium supplementation.
Conclusion: Early-onset oxalate nephrolithiasis in children warrants investigation for primary hereditary causes. A negative molecular genetic result does not eliminate the need for an extended metabolic evaluation. Magnesium deficiency may alter glyoxylate metabolism in the liver and kidneys, promoting accumulation of glyoxylate, a precursor of oxalate, and may also increase intestinal oxalate absorption, thereby increasing oxalate load. This case highlights the importance of assessing not only genetic causes of pediatric hyperoxaluria but also performing a comprehensive metabolic evaluation, including assessment of magnesium status.
Case Presentation: A 2-year-10-month-old boy with no family history of urolithiasis first developed nephrolithiasis in June 2025, at approximately 18 months of age. Computed tomography demonstrated bilateral renal calculi and pyelectasis. In July 2025, he underwent left ureteral stent placement, right-sided lumbotomy, and pyelolithotomy. Assessment of kidney function showed an estimated glomerular filtration rate (eGFR) of 75.8 mL/min/1.73 m². In April 2026, nephrolithotomy, left-sided lumbotomy, and pyelolithotomy were performed. Infrared spectroscopy of the extracted stone demonstrated 65% oxalates and 35% phosphates. Metabolic evaluation also confirmed hyperoxaluria.
Given the early age at onset, bilateral stone formation, reduced kidney filtration, and hyperoxaluria, primary hyperoxaluria was considered and molecular genetic testing was performed. Whole-exome sequencing by next-generation sequencing (NGS) detected no pathogenic variants, likely pathogenic variants, or variants of uncertain clinical significance meeting the search criteria for hereditary kidney or metabolic disorders.
In September 2026, severe hypomagnesemia was identified for the first time, with a serum magnesium concentration of 0.18 mmol/L. In view of this finding and the negative genetic evaluation, the hyperoxaluria was considered secondary and associated with magnesium deficiency. Kidney function subsequently improved, with a serum creatinine level of 34.33 µmol/L and an estimated GFR of 92.5 mL/min/1.73 m². Follow-up imaging with ultrasonography and computed tomography demonstrated reduced size of the right kidney and no calculi in the kidneys or urinary collecting system. Management included optimization of fluid intake, dietary recommendations, and magnesium supplementation.
Conclusion: Early-onset oxalate nephrolithiasis in children warrants investigation for primary hereditary causes. A negative molecular genetic result does not eliminate the need for an extended metabolic evaluation. Magnesium deficiency may alter glyoxylate metabolism in the liver and kidneys, promoting accumulation of glyoxylate, a precursor of oxalate, and may also increase intestinal oxalate absorption, thereby increasing oxalate load. This case highlights the importance of assessing not only genetic causes of pediatric hyperoxaluria but also performing a comprehensive metabolic evaluation, including assessment of magnesium status.