A 24-year-old male with end-stage renal disease (ESRD) and disproportionately high uric acid plasma concentration was admitted to our unit. After studying the patient's medical history, as well as that of the entire family, hyperuricemia was discovered in his brother, while microscopic examination of his brother's and mother's urine revealed abundant uric acid crystals. After performing purine metabolic studies, it was determined that the two siblings suffered from partial hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency (Kelley-Seegmiller syndrome). This report highlights the importance of clinical awareness and a thorough examination of the patient's medical history for establishing an early diagnosis and commencing treatment for such rare inherited metabolic disorders to prevent renal failure.