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Synonyms: include Frölich's syndrome, Obrinsky-Frölich syndrome, Eagle-Barrett syndrome, abdominal muscle deficiency syndrome, congenital absence of the abdominal muscles, Obrinsky's syndrome
This is a congenital abnormality of unknown aetiology with 3 characteristic features:
- Deficient development of the abdominal muscles, which causes the skin of the abdomen to wrinkle like a prune.
- Abnormalities of the urinary tract - usually hydronephrosis and vesico-ureteric reflux.
There may also be pulmonary hypoplasia.
It is rare with a frequency of about 1 in 30,000 live births.[1, 2] About 97% are boys.
The precise form of inheritance is unknown. It may be variable and it may often represent a new mutation. A sex-linked autosomal recessive form of inheritance has been strongly suggested.
A study from Cameroon found that most mothers were aged under 30 with singleton pregnancy but about two-thirds were complicated by placenta praevia, genital infections, pre-eclampsia, and anaemia from hookworm infestations.
Consistent features are:
- Pregnancy is complicated by oligohydramnios.
- The newborn infant has a wrinkled abdomen that looks like a prune:
- This is because the abdomen swelled with fluid in utero, then lost that fluid after birth, leading to wrinkles of excess skin.
- The appearance is accentuated by poor abdominal musculature.
- Dilated renal collecting structures and dilated bladder.
More variable findings are:
- Underdeveloped lungs.
- Cardiac anomalies.
- Gastrointestinal anomalies.
- Musculoskeletal abnormalities like talipes (clubfoot) or abnormal limbs.
The following tests are useful:
- Plain X-ray.
- Intravenous pyelogram (IVP).
- Blood tests, especially renal function (rise in blood urea suggests obstruction of the renal tract).
Other features (in order of likelihood) include:
- Malformations of the cardiopulmonary, gastrointestinal, and orthopaedic systems.
- Pulmonary hypoplasia.
- Potter facies.
- Imperforate anus.
Parents will need support and information.
Antibiotics to treat or prevent urinary tract infection.
Renal transplantation may be required. Surgical repair can be quite complex. Results seem satisfactory but the deficient abdominal wall needs repair or it causes breathing difficulties.
There is little controversy about orchidopexy but other surgery is more contentious:
- Some advocate a conservative approach.
- Others do more radical surgery at about 10 days old.
There is considerable variation in the nature of abnormalities and it is advised that the clinical condition should be as much a guide as radiological abnormalities. There can be a variety of renal, ureteric and urethral abnormalities.
Complications depend on the associated abnormalities. The most common is chronic renal failure that occurs in 25-30% of cases.
Prune belly syndrome is a serious and often life-threatening problem. Miscarriage, stillbirth and neonatal death are common.
Many infants are either stillborn or die within the first few weeks of life, from severe lung or kidney problems, or a combination of congenital anomalies. Bilateral abnormal kidneys on ultrasound or renal scan, a nadir serum creatinine above 62 μmol/L and pyelonephritis are prognostic for renal failure.
Of those who survive, successful fertility has been reported but this is usually due to modern fertility interventions.
The routine use of screening for fetal anomalies has resulted in more affected pregnancies being terminated. If an antenatal diagnosis of urinary obstruction is made, it may be possible to perform intrauterine surgery to prevent the development of prune belly syndrome. The results seem promising.[11, 12]
Further reading and references
Baird PA, MacDonald EC; An epidemiologic study of congenital malformations of the anterior abdominal wall in more than half a million consecutive live births. Am J Hum Genet. 1981 May
Ramasamy R, Haviland M, Woodard JR, et al; Patterns of inheritance in familial prune belly syndrome. Urology. 2005 Jun
Salihu HM, Tchuinguem G, Aliyu MH, et al; Prune belly syndrome and associated malformations. A 13-year experience from a developing country. West Indian Med J. 2003 Dec
Jennings RW; Prune belly syndrome. Semin Pediatr Surg. 2000 Aug
Fusaro F, Zanon GF, Ferreli AM, et al; Renal transplantation in prune-belly syndrome. Transpl Int. 2004 Oct
Noh PH, Cooper CS, Winkler AC, et al; Prognostic factors for long-term renal function in boys with the prune-belly syndrome. J Urol. 1999 Oct
Woodhouse CR; Prospects for fertility in patients born with genitourinary anomalies. J Urol. 2001 Jun
Cromie WJ, Lee K, Houde K, et al; Implications of prenatal ultrasound screening in the incidence of major genitourinary malformations. J Urol. 2001 May
Leeners B, Sauer I, Schefels J, et al; Prune-belly syndrome: therapeutic options including in utero placement of a vesicoamniotic shunt. J Clin Ultrasound. 2000 Nov-Dec
Biard JM, Johnson MP, Carr MC, et al; Long-term outcomes in children treated by prenatal vesicoamniotic shunting for lower urinary tract obstruction. Obstet Gynecol. 2005 Sep106(3):503-8.