Flow cytometric analysis demonstrated a significantly lower CD4+/CD8+ ratio in the RPBB group compared to the CG group (median [IQR]: 1.15 [0.98–1.31] vs. 1.54 [1.42–1.69], P = 0.003), indicating a potential immune imbalance in RPBB. The gene discussed is CD8A; the disease is Postural instability.