Abstract: Objective To summarize the characteristics and molecular genetics of sporadic children/adolescent-onset primary hyperparathyroidism patients and analyze the difference of characteristics betweenpatients with and without CDC73gene mutations. Methods Germline mutation analyses of the MEN1, CDC73, RET, CDKN1B, and CaSR genes were performedin 22sporadic children/adolescent-onsetPHPT patients. Their clinical data were retrospectively analyzed. Results Four patients were found to carry CDC73 mutations with the mutation rate of18%(4/22).Patients with CDC73 gene mutationshad higher rates of parathyroid carcinoma and atypical adenomas than those without，and the recurrence rate postoperatively was as high as 50%.Conclusions Genetic mutation testing should be recommended in sporadic children/adolescent-onset PHPT patients, especially the CDC73 gene.

Key words: Primary hyperparathyroidism, Children/adolescents, CDC73 gene, Parathyroid carcinoma