Objective:To examine the clinical features and genetic profiles of patients with thyroid peroxidase(TPO) gene mutations and provide diagnostic guidance for clinicians.Methods:A retrospective review of four patients with TPO mutations treated at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, from January 2014 to December 2023. Data on demographics, clinical manifestation, genotypes, treatment, and prognosis of these patients were analyzed.Results:Two males and two females, aged 13 to 27 years at diagnosis, presented with goiter as the initial symptom, with three cases menifesting during puberty. Laboratory findings showed mildly elevated or upper-limit-normal serum thyroid-stimulating hormone(TSH) levels, significantly increased free triiodothyronine/free thyroxine(FT 3/FT 4) ratios, and elevated thyroglobulin(TG) levels. Genetic testing revealed compound heterozygous pathogenic or likely pathogenic TPO mutations. Despite regular levothyroxine(L-T 4) therapy, goiter persisted. Three patients required thyroidectomy due to cosmetic or compressive symptoms, with pathology showing follicular hyperplasia. Conclusion:TPO mutations are characterized by adolescent-onset goiter, elevated FT 3/FT 4 ratios, and normal to high TSH. Genetic testing confirms the diagnosis. L-T 4 offers limited improvement, and surgery is often needed.

Objective:To examine the clinical features and genetic profiles of patients with thyroid peroxidase(TPO) gene mutations and provide diagnostic guidance for clinicians.Methods:A retrospective review of four patients with TPO mutations treated at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, from January 2014 to December 2023. Data on demographics, clinical manifestation, genotypes, treatment, and prognosis of these patients were analyzed.Results:Two males and two females, aged 13 to 27 years at diagnosis, presented with goiter as the initial symptom, with three cases menifesting during puberty. Laboratory findings showed mildly elevated or upper-limit-normal serum thyroid-stimulating hormone(TSH) levels, significantly increased free triiodothyronine/free thyroxine(FT 3/FT 4) ratios, and elevated thyroglobulin(TG) levels. Genetic testing revealed compound heterozygous pathogenic or likely pathogenic TPO mutations. Despite regular levothyroxine(L-T 4) therapy, goiter persisted. Three patients required thyroidectomy due to cosmetic or compressive symptoms, with pathology showing follicular hyperplasia. Conclusion:TPO mutations are characterized by adolescent-onset goiter, elevated FT 3/FT 4 ratios, and normal to high TSH. Genetic testing confirms the diagnosis. L-T 4 offers limited improvement, and surgery is often needed.