Characteristics of genotype of monogenic nephrolithiasis in Chinese pediatric patients with nephrolithiasis

Objective: To analyze the genotype characteristics of children with monogenic nephrolithiasis. Methods: The clinical data and genetic test results of 56 children with monogenic nephrolithiasis diagnosed and treated in Beijing Friendship Hospital, Capital Medical University from January 2016 to December 2020 were analyzed retrospectively. All pediatric patients were diagnosed by whole exome sequencing, and the genotype characteristics of the children were analyzed. Results: Among 56 children with monogenic nephrolithiasis, there were 39 males and 17 females, with an average age of 4 years (range, 5 months to 14 years). A total of 11 genes were found to have mutations, including 7 autosomal recessive genes, 1 X-linked recessive gene, and 3 genes with both recessive and dominant, of which HOGA1 gene mutation was the most common (16 cases, 28.6%), followed by AGXT gene (15 cases, 26.8%), SLC3A1 gene (6 cases, 10.7%), SLC7A9 gene (5 cases, 8.9%) and GRHPR gene (5 cases, 8.9%). The mutation types included nonsense mutations, frameshift mutations and splicing mutations, with 14 novel mutations. Genes such as AGXT, GRHPR and HOGA1 have hotspot mutations or hotspot mutation regions, which are c. 815-816 insGA and c. 33dupC mutation, c.864-865delTG mutation and c. 834-834+1 mutation region; SLC3A1 and SLC7A9 genes had 9 novel mutations, but no hotspot mutation or hotspot regions were found. Conclusion: Monogenic nephrolithiasis is rare and mostly autosomal recessive in Chinese children, with mutations in the causative genes HOGA1, AGXT, SLC3A1,SLC7A9 and GRHPR. AGXT, GRHPR and HOGA1 genes have hotspot mutations or hotspot mutation regions, and mutations may have ethnic differences.