7307JMed Genet 1992; 29: 730-732 The OEIS complex (-exstrophy- J Med Genet: first published as 10.1136/jmg.29.10.730 on 1 October 1992. Downloaded from -spinal defects): recurrence in sibs

N M Smith, H M Chambers, M E Furness, E A Haan

Abstract deficient anterior abdominal wall, and fluid The OEIS complex comprises a com- filled spaces at the back of the neck, extending bination of defects including omphalo- inferiorly on to the back. The amniotic fluid cele, exstrophy of the cloaca, imperforate volume was normal. The parents elected to anus, and spinal defects. It may represent continue the pregnancy. A glucose tolerance the most severe manifestation of a spec- test was normal. A stillborn infant was deli- trum of birth defects, the exstrophy- vered at 30 weeks' gestation after spontaneous sequence. The OEIS complex membrane rupture. affects 1 in 200 000 to 400 000 pregnancies At necropsy the fetus weighed 1110 g and and is of unknown cause. The purpose of was of indeterminate sex. The anterior abdom- the current report is to document the inal wall was absent, the viscera being partly occurrence of OEIS in sibs from separate covered by a thin walled omphalocele sac. The pregnancies and suggest that some cases bladder was exstrophied and connected to nor- may have a genetic basis. mal kidneys via narrow and ill-defined ureters (J7 Med Genet 1992;29:730-2) and the external genitalia were absent. The anus was imperforate and a spinal defect com- prising a meningocele from mid-thorax to per- In 1978 Carey et al' gave the name OEIS ineum was present. Other abnormalities in- complex to a combination of defects compris- cluded small thoracic cavities, particularly on ing omphalocele, exstrophy of the cloaca, im- the right, associated with lung immaturity and perforate anus, and spinal defects. This com- hypoplasia, fluctuant oedema in the soft tissue bination had been reported previously by of the posterior neck, severe distortion of the authors using a variety of terminologies such lower limbs with partial syndactyly of the as ectopia cloacae, vesico-intestinal fissure, second and third toes, and a single umbilical exstrophia splanchnica, and cloacal exstro- artery. The face and head were normal. The phy,1 though the first report was that of Littre diaphragms were intact and the heart was http://jmg.bmj.com/ in 1709 (quoted by Spencer2). The OEIS com- caudally positioned but normally formed with plex is rare, affecting 1 in 200 000 to 400 000 normal arterial and venous connections. Histo- pregnancies.3 It may represent the most severe logically normal testes were present. There end of a spectrum of birth defects, the exstro- were no amniotic bands. The karyotype was phy-epispadias sequence, which, in order of 46,XY. increasing severity, includes phallic separation Postmortem radiological examination with epispadias, pubic diastasis, exstrophy of showed, in addition, fusion of the right 11th

Department of on September 29, 2021 by guest. Protected copyright. Pathology, Adelaide the bladder, cloacal exstrophy, and OEIS and 12th ribs, of the right T12 and Li neural Medical Centre for complex. arches, and of the right L2 to 5 neural arches. Women and Children, Very few reports have documented recur- There were two sacral vertebral bodies. The Queen Victoria Hospital, Rose Park, rence, in sibs or offspring, of defects within the pelvis was distorted and the femora were dislo- Adelaide, South exstrophy-epispadias sequence.6 This argues cated posteriorly, and were below the 5th Australia 5067. against monogenic causation in most cases but centile in length for age (fig 1). N M Smith H M Chambers does not exclude a monogenic, multifactorial, Fifteen months after the death of this fetus, or environmental basis for some. In this report the mother gave birth to a normal female. Department of we document the features of two sibs born The mother became pregnant for the third Radiology, Queen with the features of OEIS and discuss time four months later. Ultrasound scan at 13 Victoria Hospital, briefly Adelaide, Australia. the possibility that some cases of this associ- weeks' gestation showed a major anterior ab- M E Furness ation of malformations may have a genetic dominal wall defect, caudal displacement of basis. the heart, and fluid filled spaces at the back of Department of Medical Genetics, the head, neck, and thorax. Normal ossifica- Queen Victoria tion centres at the distal spine could not be Hospital, Adelaide, Case reports identified, and there was a sac lying posterior Australia. E A Haan The first child of a non-consanguineous cou- to this area. The amniotic fluid volume was ple, the mother aged 21 and not diabetic, and normal. Pregnancy continued until 24 weeks' Correspondence to Dr Smith, Department of the father aged 38, was noted at routine ultra- gestation when spontaneous membrane rup- Paediatric Pathology and sound scan at 18 weeks' gestation to have ture occurred. A stillborn fetus weighing 329 g Cytogenetics, Royal Hospital for Sick Children, 2 several abnormalities. There was a raised was delivered. Rillbank Crescent, maternal serum a fetoprotein level. Detailed At necropsy (fig 2) a large omphalocele was Edinburgh EH9 ILF. ultrasound scan at 22 weeks' gestation showed noted, there were no demonstrable internal or Received 4 January 1992. a severe the bladder was Revised version accepted single fetus with kyphoscoliosis, external genitalia, and urinary 30 March 1992. poorly defined lumbar spine, small thorax, exstrophied and connected via narrow ureters The OEIS complex (omphalocele-exstrophy-imperforate anus-spinal defects): recurrence in sibs 731

rotation and distortion of the lower spine and pelvis, with the femora lying posterior to the trunk. They were at the 5th centile in length J Med Genet: first published as 10.1136/jmg.29.10.730 on 1 October 1992. Downloaded from for age.

Discussion Carey et all in 1978 reported 10 patients with OEIS and stated that "no familial cases have been described" and that "since there have not been any families who had had more than one affected child in the literature or in our series, there is no evidence that the OEIS complex is an inherited entity". The purpose of this re- port is to document the occurrence of OEIS in sibs from separate pregnancies and thereby to suggest that some cases of this association of malformations may have a genetic basis. Both of the cases described above showed omphalocele, exstrophy of the cloaca, imper- forate anus, and spinal defects (severe kypho- Figure 1 AP x ray of case 1. Arrow on right, meningocele. Arrow on left, extruded abdominal viscera. scoliosis and meningocele). The presence of large postnuchal fluid collections in both cases is of interest and is considered to represent obstruction to kidneys showing hydronephrotic changes. jugular lymphatic sequence. There were no amniotic bands on the placental The anus was imperforate and the spine surface and none of the craniofacial defects showed a pronounced kyphoscoliosis with shortening of the vertebral column. Other ab- typically found in early amnion rupture se- normalities included hypoplasia of the lungs, quence.7 No history of maternal diabetes mel- litus, or of hydantoin administration, both of flexion contractures of the lower limbs, over- which have been associated with OEIS, was lapping of fingers with no syndactyly, oedema obtained in our cases.' An OEIS-like complex of the posterior neck soft tissue, and a single can occur in trisomy 18, but the in umbilical artery. The face and head were oede- karyotypes matous but otherwise normal. The the current cases were normal male 46,XY and diaph- normal female 46,XX."I ragms were intact and the heart was normally Recurrence of omphalocele or bladder formed with normal arterial and venous con- nections, though caudally positioned. There exstrophy in sibs has been documented, with a

risk of less than OEIS (referred to as http://jmg.bmj.com/ were no amniotic bands. The karyotype 1%.1 cloacal exstrophy) has been reported in both was 46,XX. Postmortem radiology showed of a pair of monozygotic twins on two occasions, but recurrence in sibs born in separate preg- nancies has not been previously reported.45 Defects within the epispadias-exstrophy sequence (exstrophy of the bladder, cloacal OEIS do recur exstrophy, complex) but this is on September 29, 2021 by guest. Protected copyright. clearly uncommon. The point has been made, however, that the published rates of occur- rence and recurrence of conditions within this spectrum, some based on surgical data, are likely to be spuriously low, as some of the patients may die without treatment shortly after birth or be stillborn or be classified as omphalocele only, where this is the most prominent abnormality.89 Part of the definition of OEIS is exstrophy of the cloaca.' Opinions differ about the pos- sible existence of a continuum of abnormalities ranging from epispadias to to cloacal exstrophy. Carey et al,' in their original article, clearly separated OEIS from exstrophy ofthe bladder. Some writers suggest that there may be a spectrum of defects rang- ing from penile epispadias, through bladder exstrophy, and cloacal exstrophy, to OEIS.3 Kutzner et all are clearly of the latter view when saying that the definition of OEIS in- cludes exstrophy of the bladder. The occurrence of exstrophy of the bladder Figure 2 Lateral view of external appearance of appears to be more frequent at 1:30000 to case 2. 40 000 births6 than exstrophy of the cloaca at 732 Smith, Chambers, Furness, Haan

1:200 000 to 250 000,45 or OEIS at 1:200000 to have had an affected child.'0 The mother of the 400000.3 Markedly different rates of occur- sibs described is not known to have been

rence are suggested for cloacal exstrophy by exposed to a potential teratogen and the sibs J Med Genet: first published as 10.1136/jmg.29.10.730 on 1 October 1992. Downloaded from Gosden and Brock9 at 1:10000 to 15000. were conceived two years apart, making an Clearly, precise definition of terms remains a environmental cause unlikely. There is no problem. compelling evidence that genetic factors have a Given the lack of certain knowledge regard- role in the causation of OEIS complex and ing the aetiology of either bladder exstrophy or related birth defects, but our cases indicate cloacal exstrophy, it seems reasonable to ac- that they may do so in some instances. cept that an event such as failure of cloacal 1 Carey JC, Greenbaum B, Hall BD. The OEIS complex septation or cloacal membrane breakdown (omphalocele, exstrophy, imperforate anus, spinal de- fects). Birth Defects 1978;14:253-63. during the fourth to sixth week of intrauterine 2 Spencer R. Exstrophia splanchnica (exstrophy of the clo- life may have the potential to cause abnormal- aca). Pediatr Surg 1965;57:751-66. 3 Hurwitz RS, Manzoni GAM, Ransley PG, Stephens FD. ities in the adjacent lumbrosacral somites, Cloacal exstrophy: a report of 34 cases. J Urol depending upon the severity of the original 1987;138:1060-4. 4 Redman JF, Seibert JJ, Page BC. Cloacal exstrophy in abnormality.'9 Notwithstanding the differing identical twins. Urology 1981;17:73-4. views on the presence or absence of an epispa- 5 McLaughlin JF, Marks WM, Jones G. Prospective management of exstrophy of the cloaca and myelocysto- dias-OEIS spectrum, the appearances in the cele following prenatal ultrasound recognition of neural two cases we describe are in accord with the tube defects in identical twins. Am J Med Genet 1984;19:721-7. original description of Carey et al.1 6 Higgins CC. Exstrophy of the bladder: report of 158 cases. Possible explanations for the recurrence in- Am Surg 1962;28:99-102. 7 Kutzner DK, Wilson WG, Hogge WA. OEIS complex clude autosomal recessive inheritance, multi- (cloacal exstrophy): prenatal diagnosis in the second tri- factorial inheritance, gonadal mosaicism for a mester. Prenat Diagn 1988;8:247-53. 8 Evans JA, Darrill KD, Trevenen C, Rockman-Greenberg dominant mutation, an environmental factor, C. Cloacal exstrophy and related abdominal wall defects or subclinical maternal disorder. The latter in Manitoba: incidence and demographic factors. Clin Genet 1985;27:241-51. possibility, while speculative, has a parallel in 9 Gosden C, Brock DJH. Prenatal diagnosis of exstrophy of recent evidence that periconceptional folic acid the cloaca. Am J Med Genet 1981;8:95-109. 10 Medical Research Council Vitamin Study Research Group. supplementation can reduce the risk of recur- Prevention of neural tube defects: results of the MRC rence of neural tube defects for couples who Vitamin Study. Lancet 1991;338:131-7. http://jmg.bmj.com/ on September 29, 2021 by guest. Protected copyright.