Phenotypic severity scoring system and categorisation for prune belly syndrome: application to a pilot cohort of 50 living patients

OBJECTIVE: To design a novel system of scoring prune belly syndrome (PBS) phenotypic severity at any presenting age and apply it to a large pilot cohort. PATIENTS AND METHODS: From 2000 to 2017, patients with PBS were recruited to our prospective PBS study and medical records were cross-sectionally analysed, generating individualised RUBACE scores. We designed the pragmatic RUBACE-scoring system based on six sub-scores (R: renal, U: ureter, B: bladder/outlet, A: abdominal wall, C: cryptorchidism, E: extra-genitourinary, generating the acronym RUBACE), yielding a potential summed score of 0-31. The 'E' score was used to segregate syndromic PBS and PBS-plus variants. The cohort was scored per classic Woodard criteria and RUBACE scores compared to Woodard category. RESULTS: In all, 48 males and two females had a mean (range) RUBACE score of 13.8 (8-25) at a mean age of 7.3 years. Segregated by phenotypic categories, there were 39 isolated PBS (76%), six syndromic PBS (12%) and five PBS-plus (10%) cases. The mean RUBACE scores for Woodard categories 1, 2, and 3 were 20.5 (eight patients), 13.8 (25), and 10.6 (17), respectively (P < 0.001). CONCLUSIONS: RUBACE is a practical, organ/system level, phenotyping tool designed to grade PBS severity and categorise patients into isolated PBS, syndromic PBS, and PBS-plus groups. This standardised system will facilitate genotype-phenotype correlations and future prospective multicentre studies assessing medical and surgical treatment outcomes.