Prune Belly Syndrome (PBS) is a very rare (3.8/100,000 live births) congenital disease that predominantly affects males.
PBS is characterized by a triad of
- Anterior abdominal wall muscle deficiency
- Urinary tract abnormalities
- Bilateral cryptorchidism.
Termed prune belly due to the wrinkled appearance of the abdominal wall at birth, it is a multisystem disease that can affect the genitourinary tract, cardiopulmonary, GI and musculoskeletal systems. Some studies and the inheritance pattern suggest that the disease is due to a recessive X-linked defect. However, other studies have demonstrated a deletion in the the hepatocyte nuclear factor 1 beta (HFN1B) gene on chromosome 17q12 resulting in defective mesenchymal development, thus suggesting autosomal dominant inheritance. A clear genetic basis for PBS has not yet been established.
As per Seidal et al., nearly one-half of patients surviving infancy will develop CKD and nearly one third will develop ESRD and require RRT. This is thought to occur largely due to incomplete nephron differentiation, dilation of tubules, interstitial fibrosis and eventual glomerulosclerosis. Clinically PBS can be associated with reflux nephropathy and recurrent pyelonephritis.
Often diagnosed at birth or in early childhood, PBS can be diagnosed by antenatal ultrasound between weeks 20-30 with features including hydroureteronephrosis with or without echodense kidney parenchyma, oligohydramnios, hypoplastic lungs and bulging abdomen.
Therapy in childhood remains controversial, but can require early surgery for urine drainage in order to prevent recurrent infections or antibiotic prophylaxis. Maintenance CAPD and HD are equally effective in the management of ESKD and kidney transplantation has been successfully performed with excellent long-term prognosis.
Sapna Shah, MD
2nd Year Nephrology Fellow
Icahn School of Medicine, Mount Sinai, New York