Clinical features and mutational spectrum of Chinese patients with primary hyperoxaluria type 2

Primary hyperoxaluria type 2 (PH2) is a rare hereditary disease that causes nephrolithiasis, nephrocalcinosis and kidney failure. This study aimed to investigate the clinical features and mutational spectrum of Chinese patients with PH2. A retrospective cohort study was performed on PH2 patients admitted to our center over seven years. We also systematically reviewed all the articles on Chinese PH2 patients published from January 2000 to May 2023 and conducted a meta-analysis. A total of 25 PH2 patients (10 from our center and 15 from published studies) were included in this study. The median age of onset in patients from our center was 8.50 (1.00, 24.00) years, and 50% were male. Among the full cohort of 25 Chinese patients, the median age of onset was 8.00 (0.40, 26.00) years, and 64% of them were male. Seven patients progressed to end-stage kidney disease, with a median age of 27.50 (12, 31) years. The cumulative renal survival rates were 100%, 91.67%, 45.83% and 30.56% at 10, 20, 30 and 40 years of age, respectively. A total of 18 different variants were identified, and c.864_865del was the dominant variant, accounting for 57.69% of the total alleles. Patients who were heterozygous for c.864_865del were more susceptible to nephrocalcinosis than those who were homozygous for c.864_865del and those harboring other mutations (83.33% versus 33.3% and 0%, respectively) (p = 0.025). The clinical features and mutational spectrum of Chinese PH2 patients were described. This study helps to expand awareness of the phenotypes and genotypes of Chinese PH2 patients and contributes to the improvement of diagnostic and treatment strategies for PH2 patients.