Premium
Concordant partial urorectal septum malformation sequence in monozygotic twins
Author(s) -
Lubusky Marek,
Prochazka Martin,
Dhaifalah Ishraq,
Halek Jan,
Mickova Ivana,
Santavy Jiri
Publication year - 2006
Publication title -
american journal of medical genetics part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.064
H-Index - 112
eISSN - 1552-4833
pISSN - 1552-4825
DOI - 10.1002/ajmg.a.31523
Subject(s) - ectromelia , oligohydramnios , cloaca , sequence (biology) , monozygotic twin , biology , pregnancy , medicine , anatomy , fetus , genetics , virus
To the Editor:The urorectal septum malformation (URSM)sequence is dened as the absence of the perinealand anal opening in association with ambiguousgenitalia and urogenital, colonic, and lumbosacralanomalies. The URSM sequence is usually lethal inthe newborn period due to pulmonary hypoplasiaresultingfromsevereoligohydramnios.Theabnorm-alities of this condition are though to arise early indevelopment due to incomplete subdivision of theprimitivecloacaandlackofbreakdownofthecloacalmembrane[Escobaretal.,1987;Wheeleretal.,1997].AlesssevereformofURSMsequenceisreferredtoby Wheeler and Weaver [2001] as the partial URSMsequence.IndividualswithapartialURSMsequencetypically have a single perineal/anal opening thatservesasanoutletforacommoncloacaandconduitfor urine and feces to the outside. It is important todifferentiatethepartialfromthefullURSMsequencebecausetheprognosisinthepartialURSMsequenceisgenerallygood,withlong-termsurvivalacommonfeature.In this article we report a case of monozygotictwins concordant for the milder and generallynonlethalformoftheURSMsequence.Monozygotictwinningwiththisconditionhasnotbeenpreviouslyreported.The mother, a 19-year-old Caucasian woman,gravida 1, para 0, was presented to the ultrasoundunit of the department of medical genetics and fetalmedicineat18weeksofspontaneouspregnancyforroutine screening. There was no family history ofcongenital malformations. The mother denied ter-atogenic exposure. On sonographic examination, amonochorionic, diamniotic twin pregnancy wasdiagnosed. Twin A had dilated distal bowel loopswith enterolithiasis (an ultrasonographic examina-tionrevealedanechogenicbowelwithmultiplefociof calcied meconium intraluminally). Twin B haddilated distal bowel loops. A possible diagnosis ofanal atresia was made. The genitalia could not beclearly determined. In view of the abnormal sono-graphic ndings, amniocentesis was performed.Both fetuses had a normal 46,XY karyotype. Thepatient was referred to the high-risk clinic. Fetalbiometry was appropriate for gestational age and anormal amount of amniotic uid was observed. Tofurther exclude anorectal malformation, magneticresonance imaging (MRI) was performed whichdemonstrated dilated distal bowel loops (withenterolithiasis in twin A). The parenchyma of thekidneys and urinary bladder appeared normal. Thetwins were delivered by cesarean at 35 weeks ofgestationafterprematuremembranerupture.TwinAweighed 1,950 g, twin B weighed 2,350 g. Post-partum examination revealed close placental inser-tions of both umbilical cords, each containing threevessels. Over a length of 25 cm the umbilical cords,separatedbyamnioticmembranes,raninsuchcloseproximity that they appeared to have a commoncourse. The monochorionic, diamniotic twin preg-nancy was conrmed and concordant fetal abnorm-alities were diagnosed. Both neonates had a single