In this study, 28 children with SDNS/frequent relapsing nephrotic syndrome (FRNS) aged 13.68 ± 0.77 years were enrolled, and the numbers of T and B cell subsets were measured by flow cytometry in SDNS/FRNS children and healthy control children of the same age, including CD19+ B cells (total B cells), transitional B cells, mature B cells, memory B cells, IgM memory B cells, transformed memory cells, CD3+ T cells, CD4+ T cells, and CD8+ T cells. The gene discussed is CD19; the disease is Fryns syndrome.