The syndromology of anorectal malformation (atresia, stenosis, ectopia)

Anorectal malformation and Down's syndrome in monozygotic twins

Anorectal malformation (ARM) can be divided in high, intermediate, and low forms according to the level of termination of the rectum in relation to the pubococcygeal and ischiatic lines. Patients with Down's syndrome have a high incidence of gastrointestinal anomalies, such as tracheoesophageal fistula, duodenal obstruction, annular pancreas, Hirschsprung's disease, and ARM. In these children, ARM is generally low with or without a fistula. The mode of inheritance of ARM and its genetic relation with Down's syndrome is not known, even if the association (ARM-Down's syndrome) seems not to be coincidental. We describe here a very rare case of monozygotic twins born with the association of ARM and Down's syndrome.

Magnetic resonance imaging in children with anorectal malformations: embryologic implications

PURPOSE

The aim of this study was to evaluate the spectrum of developmental anomalies in the caudal region of patients with anorectal malformations (ARM) and relate them to the new insights in the embryogenesis of this region.

METHODS

Forty-nine patients with ARM were investigated with magnetic resonance imaging (MRI); 24 preoperatively (preop) and 25 postoperatively (postop). Of this group, 17 patients had a high (or intermediate) ARM, 28 a low ARM, and 4 a cloacal malformation (CM). The evaluation of the imaging studies included the level and type of ARM (preop); the developmental state of the sphincter muscle complex (SMC); and the associated anomalies of spinal cord, spine, and urogenital system. The anomalies detected were ordered and related to recent embryologic observations in the caudal region.

RESULTS

With MRI, the level of ARM was depicted effectively in 23 of 24 patients (96%) investigated preop, including 5 of 9 clinically proven fistulae in those with high ARM and CM (56%). Maldevelopment of the SMC was observed in 14 of 49 patients (29%). Associated anomalies of spinal cord and spine were found in 51% of patients, more frequently in those with high ARM, low ARM with fistulae, and cloacal malformations. Associated anomalies of the urogenital system were found in 37% of patients.

CONCLUSIONS

As illustrated by the current study, MRI has become indispensable for the visualization of the nature of congenital ARM and associated anomalies. Moreover, MRI aids in understanding the morphology and pathogenesis of these complex congenital malformations. Based on the MRI and recent embryologic observations, a new and simplified classification of ARM is introduced, including a more appropriate nomenclature.

Inheritance of familial congenital isolated anorectal malformations: case report and review

We report on a 3-generation family with 4 members affected with congenital low anorectal malformations. The vertical segregation of the anomalies and the occurrence of affected males and females support autosomal-dominant inheritance, which was suggested previously for this type of congenital anomaly.

New familial syndrome of unilateral upper eyelid coloboma, aberrant anterior hairline pattern, and anal anomalies in Manitoba Indians

We report on 6 (3 male, 3 female) Manitoba Indian children with hypertelorism and variable combinations of unilateral eye malformations, aberrant anterolateral scalp hairline, and nasal and anal anomalies. These children belong to 4 related families. The parents and 7 other sibs are clinically unaffected. The family histories are otherwise unremarkable. The presence of 2 major malformations in sibs and related individuals (with unaffected parents) suggests that this is a newly described pleiotropic autosomal recessive syndrome. The differential diagnosis includes cryptophthalmos syndrome and several other related malformation syndromes. Although multifactorial determination cannot be excluded, the inbred, isolated population and distribution make autosomal recessive inheritance more likely.

Sacrococcygeal dysgenesis association

In the malformation analysis of 445 patients ascertained only for a sacrococcygeal malformation, a new phenotype, the sacrococcygeal dysgenesis association (SDA), was delineated in 34%. In addition, sirenomelia patients were found in 12%, the VATER association in 27%, and 27% could not be classified. Heterogeneity in the patients with sacrococcygeal malformations was identified by the differences found in their associated malformations. SDA patients have a relatively small average number (3.3) of anomalies per patient as compared with 9.3 in sirenomelia and 6.2 in VATER patients. SDA abnormalities occurred to a significant degree only in 6 of 20 designated malformation categories (vertebral, rib, pelvic, lower limb, central nervous system [CNS], renal) in contrast to 17 in VATER and 18 in sirenomelia patients. The SDA vertebral malformation pattern also differed from that of VATER/sirenomelia patients as did the high sacrococcygeal agenesis:dysgenesis ratio and low thoracolumbar vertebrae and/or rib hypersegmentations. Most significantly, SDA patients had a large number of CNS anomalies and CNS-related dysfunctions of the urinary and distal intestinal tracts but no anatomic urinary or intestinal tract malformations. This contrasted sharply with the markedly increased occurrences of anatomic abnormalities in these body regions of the sirenomelia and VATER patients. Demographic data such as patient survival, twinning and, particularly, the high (28%) incidence of maternal diabetes in the SDA further support its differentiation from VATER/sirenomelia patients.

Familial caudal dysgenesis: evidence for a major dominant gene

Four sibs with varying degrees of caudal dysgenesis are described. Case 1 showed aberrant umbilical cord vasculature with a single umbilical artery near the placental insertion. Cases 2 and 3 showed full sirenomelia, one with a complex congenital heart defect. Case 4 had an imperforate anus and an excessively long umbilical cord. The father's half-sib had an imperforate anus, rectovaginal fistula and genitourinary anomalies. A dominant gene with reduced penetrance is likely.

The Townes-Brocks syndrome

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Anorectal malformations and Down syndrome

During 1980 to 1986, 89 children with Down syndrome and 42 with imperforate anus were diagnosed among 64,870 liveborn infants in the Jewish population of Jerusalem. Two of the children had both Down syndrome and imperforate anus. This indicates a high incidence of imperforate anus among children with Down syndrome (2.2%).

Interpretation of some median anomalies as illustrated by cyclopia and symmelia

Anomalies that involve the median plane are heterogeneous, and their embryological basis varies widely. Cyclopia and symmelia present a number of similarities: 1) They would appear to arise by neither fusion nor merging but mainly through a failure in lateralization. 2) Mesenchymal deficiency is important in both: possibly disturbance of the prechordal plate in cyclopia and failure of the caudal eminence in symmelia. The caudal eminence is an important developmental feature that is only recently becoming clearer in the human embryo. 3) Disturbance of axial material seems to be essential in both. 4) The results of experimental teratogenesis and an analysis of normal human development confirm that these conditions arise early. The teratogenetic termination-periods in the human are probably 2 1/2 weeks for cyclopia sensu stricto (a median eye in a single orbit) and 3 weeks for cyclopia sensu lato, i.e., synophthalmia (paired ocular structures in a single orbit); 2 1/2 weeks for symmelia of the upper limbs (e.g., in cephalothoracopagus) and 3 1/2 weeks for symmelia of the lower limbs in a single individual. It is pointed out that in symmelia the limb buds, upper or lower, have failed to separate at their postaxial margins. This is in contrast to dimelia, in which the preaxial borders are missing and the postaxial margins are duplicated (postaxial dominance).

A new family with the Townes-Brocks syndrome

We describe a new family with the Townes-Brocks syndrome, a dominantly inherited syndrome of anal, urorenal, ear and limb malformations. The proband shows the full spectrum of anomalies, including imperforate anus, prominent perineal raphe, rectoperineal fistula, triphalangeal thumb, preaxial hexadactyly, syndactyly, clinodactyly, preauricular protuberances, hypoplastic satyr ears, sensorineural hearing loss and urorenal anomalies. In contrast, the father shows only limb anomalies, sensorineural hearing loss and renal anomalies. Anorectal malformations, which are present in almost every patient with the Townes-Brocks syndrome, were absent in the father. This case report illustrates the intrafamilial variability of the Townes-Brocks syndrome. Consequently, careful examination of relatives of patients with this syndrome is necessary for the differential diagnosis with the sporadically inherited VA(C)TER(L) association.

Anorectal malformation: familial aspects and associated anomalies

One hundred and sixty nine patients with anorectal malformation were studied: there were 108 boys, 60 girls, and one case of intersex. Low malformations were more common in both sexes. Over half the subjects had associated malformations. These were more common in the group with high malformations. There was no difference between the sexes in this respect. A family history of similar malformation was found in 15 cases (9%). Where anorectal malformation was the only abnormality in the family an autosomal dominant mode of inheritance was likely, except in one case where there was consanguinity. Where there were associated malformations no single mode of inheritance emerged. Two families with probably hitherto unrecognised recessive syndromes are described. In most cases of anorectal malformation the recurrence risk is low. Multiple associated malformations may indicate recessive inheritance and subsequent pregnancies should be regarded as high risk and full antenatal investigative facilities provided.

Townes syndrome. A distinct multiple malformation syndrome resembling VACTERL association

An 8-year-old male is presented with clinical findings of Townes syndrome in an otherwise unaffected family. Additional abnormalities possibly representing low frequency associations of this autosomal dominant multiple malformation syndrome included a cardiac defect and hypospadias. Similarities exist between Townes syndrome and VACTERL association, which is generally regarded to be sporadic in nature. Recognition of Townes syndrome as a distinct entity is critical for implementing appropriate management in early childhood, including amplification of hearing impairments. Variable expressivity may occur in this disorder. Careful evaluation must be made, therefore, of the parents of an affected infant with an apparent sporadic case, in order to provide the couple with an accurate recurrence risk at genetic counseling.

An association of caudal malformations arising from a defect in the "axial mesoderm" developmental field

We have studied two newborn infants with a remarkable genital malformation, failure of urethral development with enormous bladder distension, atresia of the distal hindgut, vertebral abnormalities, and compression deformities. This is a pattern of anomalies similar to, and probably an extension of, the association of female pseudohermaphroditism and other anomalies (FPA) described by Lubinsky [Am J Med Genet 6:123-136, 1980]. We propose that its pathogenesis involves a defect expressed in mesoderm, especially caudal mesoderm. We offer some speculation on what might be its nature, with particular reference to the theory of cell surface molecules having a role in morphogenesis. We apply the concept of the developmental field to provide a clarifying perspective.

Familial incidence of congenital anorectal anomalies

We describe two families with pedigrees over three and two generations with nine members affected with anorectal malformations. Both pedigrees are compatible with autosomal dominant inheritance with variable penetrance and expression or with multifactorial inheritance with a high genetic load. The recurrence risk is thought to be in the range of 10% to 20% for first degree relatives of affected members.

Cardiovascular anomalies with imperforate anus

In 68 patients with anorectal malformations cardiovascular anomalies (CVA) were seen in 15 and genitourinary (GU) anomalies in 30. CVA were more frequent (33%) whenever there was a GU anomaly. Ventricular septal defect was the most frequent lesion. All but 1 CVA occurred with type III anorectal malformation. The complexity of the cardiac lesion did not parallel that of the GU anomaly.

Dominant ano-rectal malformation, nephritis and nerve-deafness: a possible new entity?

A family is presented in which ano-rectal malformation and features common to Alport Syndrome appear to be present in three generations. The possibility of a new syndrome based on a single gene defect is discussed.

Anal atresia and the Klein-Waardenburg syndrome

A 3-month-old male infant with type I Klein-Waardenburg syndrome with an imperforated anus and a perineal fistula is reported. The possible association of this gastrointestinal malformation with the KW syndrome is discussed.

Spondylocostal dysostosis associated with anal and urogenital anomalies in a Mennonite sibship

Spondylocostal dysostosis, anal atresia, and urogenital anomalies were observed in two male infants of a consanguineous Mennonite couple. A careful review of previously reported syndromes of severe vertebral abnormalities and/or imperforate anus suggests that our patients have a previously undescribed recessive disorder that should be included in the differential diagnosis of rib and vertebral anomaly syndromes.

Congenital hypothalamic hamartoblastoma, hypopituitarism, imperforate anus and postaxial polydactyly--a new syndrome? Part I: clinical, causal, and pathogenetic considerations

We report on six infants with a neonatally lethal malformation syndrome of hypothalamic hamartoblastoma, postaxial polydactyly, and imperforate anus. Some, but not all, patients had laryngeal cleft, abnormal lung lobulation, renal agenesis and/or renal dysplasia, short 4th metacarpals, nail dysplasia, multiple buccal frenula, hypoadrenalism, microphallus, congenital heart defect, and intrauterine growth retardation. The infants also had hypopituitarism and hypoadrenalism. All were sporadic cases, parents were not consanguineous, chromosomes were apparently normal. Family histories were unremarkable. There was insecticide and/or herbicide exposure in several of the cases, but no exposures were common to all 6 mothers. Five of the patients were born within an 8-month period, but all in different geographic locations. It is postulated that this is a previously apparently unreported syndrome of presently unknown cause.