To evaluate the clinical properties of patients with nutcracker syndrome (NCS).

The medical records of the patients with NCS were retrospectively investigated, and the patients' sex, age, presenting symptoms, urinalysis findings, associated diseases, and body mass indexes were recorded.

A total of 23 nonconsanguineous patients (11 male and 12 female patients, mean age 141 ± 36 months). Two patients had posterior NCS. Seventeen patients presented with 1 or >1 symptom. Fatigue and lassitude (n = 1), flank pain (n = 8), abdominal pain (n = 7), varicocele (n = 2), and macroscopic hematuria (n = 9) were the presenting symptoms. Only 6 patients had received a diagnosis of NCS from the urinalysis findings, which revealed microscopic hematuria or non-nephrotic proteinuria. The urinalysis findings disclosed isolated proteinuria in 6, hematuria plus proteinuria in 8, and macroscopic hematuria in 9 patients. Orthostatic proteinuria was detected in 7 patients. In patients with regressed hematuria and proteinuria, the body mass index was markedly increased at the end of the follow-up period relative to at diagnosis (at diagnosis 16.9 ± 4.0 kg/m²; at the end of the follow-up period 18.6 ± 4.6 kg/m²; P = .028).

The diagnosis of NCS should be considered in the presence of symptoms such as proteinuria and hematuria and should be absolutely ruled out before attempting renal biopsy. An apparent correlation between an increased body mass index and regression of symptoms was seen.