Chondrodysplasia, situs inversus totalis, cleft epiglottis and larynx, hexadactyly of hands and feet, pancreatic cystic dysplasia, renal dysplasia/absence, micropenis and ambiguous genitalia, imperforate anus

Significance of bifid epiglottis

Bifid epiglottis is a rare anomaly, which is heterogeneous and is often associated with other anomalies, particularly polydactyly. It has been reported in 40% of patients with Pallister-Hall syndrome and rarely in other syndromes. We report two brothers with bifid epiglottis who also have features suggestive of Bardet-Biedl syndrome. We also review the features seen in 22 patients reported in the literature with bifid epiglottis. No patient had bifid epiglottis as an isolated anomaly. Other malformations include clefts, micropenis, renal abnormalities, anal malformations, hypospadias, hypothalamic hamartomas, hypopituitarism, heart defects, and Hirschprung disease. Bifid epiglottis may be an under-recognized feature of Bardet-Biedl syndrome and should be considered in these patients, particularly if there are airway symptoms. Many of the anomalies associated with bifid epiglottis have potentially serious consequences and thus, a thorough evaluation of the patient with bifid epiglottis is warranted.

Specific congenital heart defects in RSH/Smith-Lemli-Opitz syndrome: postulated involvement of the sonic hedgehog pathway in syndromes with postaxial polydactyly or heterotaxia

BACKGROUND

RSH/Smith-Lemli-Opitz syndrome is an autosomal recessive syndrome due to an inborn error of cholesterol metabolism and is characterized by developmental delay, facial anomalies, hypospadias, congenital heart defect (CHD), postaxial polydactyly, and 2-3 toe syndactyly. CHD is found in half of the propositi, and a specific association with atrioventricular canal defect (AVCD) and anomalous pulmonary venous return has been demonstrated.

METHODS

We report on an additional patient with RSH/SLOS presenting with complete AVCD and anomalous pulmonary venous return, and discuss the possible relationship of the Sonic Hedgehog (SHH) pathway as causative factor of these CHDs and those in heterotaxia patients with postaxial polydactyly syndromes.

RESULTS

Anatomic similarities between heterotaxia and CHDs of several syndromes with postaxial polydactyly have been noted previously, considering the frequent association of AVCD with common atrium in these conditions. It is known that both CHDs of heterotaxia and postaxial polydactyly can be related to abnormalities of the SHH pathway. Cholesterol has a critical role in the formation of normally active hedgehog proteins. It could be hypothesized that specific types of CHDs in RSH/SLOS can be caused by modifications of the SHH protein related to the defect of cholesterol biosynthesis.

CONCLUSIONS

The specific association of AVCD and anomalous pulmonary venous return in patients with RSH/SLOS and the finding of AVCD +/- common atrium in several syndromes with polydactyly leads to the hypothesis that heterotaxia due to SHH anomalies could be involved in a large spectrum of conditions. Perturbations in different components of the SHH pathway could lead to several developmental errors presenting with partially overlapping clinical manifestations.

Liver fibrocystic disease and polydactyly: proposal of a new syndrome

Liver fibrocystic disease (LFCD), characterized by dilatation of the intrahepatic bile ducts and variable degree of fibrosis, can be present alone or as part of many syndromes, such as Bardet-Biedl syndrome (BBS), Meckel syndrome, Jeune asphyxiating thoracic dysplasia, and Fraser-Jequier-Chen syndrome. We report two cases of LFCD and polydactyly with features similar, but not diagnostic of, BBS. Patient 1 was an 18-month-old boy with mental retardation, polydactyly, chronic renal failure, convergent strabismus, and hepatic fibrosis. Patient 2 was a male neonate with LFCD and polydactyly. Their manifestations could not be diagnosed as any of the previous mentioned entities. Difficulties in the early diagnosis of BBS have been previously reported and this could explain the clinical variability and heterogeneity of manifestations at the time of diagnosis. On the other hand, the existence of liver abnormalities in association with BBS has been previously described, but is rare. Our patients' malformations might represent a new entity where autosomal recessive inheritance is probable, but other patterns cannot be ruled out.

Situs inversus totalis

The etiology of situs inversus totalis remains uncertain. However, the literature establishes that isolated situs inversus totalis is usually asymptomatic in the neonate. This case study illustrates the importance of physical assessment skills in identifying situs inversus totalis in the neonate. Current research may reveal the etiology of this rare but fascinating abnormality.

The Smith-Lemli-Opitz syndrome

The Smith-Lemli-Opitz syndrome (SLOS) is one of the archetypical multiple congenital malformation syndromes. The recent discovery of the biochemical cause of SLOS and the subsequent redefinition of SLOS as an inborn error of cholesterol metabolism have led to important new treatment possibilities for affected patients. Moreover, the recent recognition of the important role of cholesterol in vertebrate embryogenesis, especially with regard to the hedgehog embryonic signalling pathway and its effects on the expression of homeobox genes, has provided an explanation for the abnormal morphogenesis in the syndrome. The well known role of cholesterol in the formation of steroid hormones has also provided a possible explanation for the abnormal behavioural characteristics of SLOS.

Cardiac malformations in patients with oral-facial-skeletal syndromes: clinical similarities with heterotaxia

Oral-facial-skeletal (OFS) syndromes include short rib-polydactyly (SRP) and oral-facial-digital (OFD) syndromes. Congenital heart defect (CHD), mainly atrioventricular canal defect (AVCD), is a cardinal finding in the Ellis-van Creveld (EVC) syndrome, but it occurs only occasionally in other SRP and OFD syndromes. The cardiac characteristics of all patients with OFS syndromes evaluated at our hospital from January 1986 to April 1997 were analyzed and compared with published reports. Ten patients with EVC syndrome, one with McKusick-Kaufman syndrome, and one with OFD syndrome type II had AVCD. Eight patients (67%) had a common atrium, eight (67%) a persistent left superior vena cava (LSVC) draining into the left atrium because of an unroofed coronary sinus in five (42%), and left-sided obstructive lesions in three (25%). One patient with EVC syndrome had AVCD, common atrium, double outlet right ventricle, persistent LSVC associated with "asplenia syndrome," visceral heterotaxia, and right isomerism. The combination of CHDs found in the personal series of OFS syndromes suggests pathogenetic similarity with heterotaxia syndromes. Published results also corroborate the association between OFS syndromes and CHDs usually occurring in heterotaxia. Molecular studies could shed light on the genetic mechanisms implicated in the cause of the OFS and heterotaxia syndromes.

Abnormal cholesterol biosynthesis as in Smith-Lemli-Opitz syndrome disrupts normal skeletal development in the rat

Smith-Lemli-Opitz syndrome (SLOS) in human infants is a common autosomal recessive malformation syndrome (estimated incidence, 1:20,000). It is characterized clinically by congenital anomalies, especially craniofacial and limb defects, and biochemically by a defect in 7-dehydrocholesterol-delta7-reductase activity (7DHC-reductase), the final enzyme in cholesterol biosynthesis. In previous studies, early administration of the 7DHC-reductase inhibitor AY9944 to pregnant rats resulted in a high frequency of holoprosencephaly, relevant to craniofacial anomalies of SLOS. In order to test the effect of AY9944 on limb development, we treated dams on gestation day 7 (GD7), which delays the biochemical defect to about GD13 to GD14. Sera were sampled on GD12, GD14, and GD21 and cholesterol and dehydrocholesterols (7DHC and 8DHC) were measured by gas-chromatography-mass spectrometry (GC-MS), as for the diagnosis of SLOS. GD21 fetuses were examined for gross malformations and skeletal development. In treated dams, the SLOS biochemical marker 7DHC accounted for one fourth and one third of total sterols, respectively, on GD12 and GD14, and cholesterolemia on these two gestation days was reduced by 50% and 43%, respectively, as compared with control values. This maternal metabolic defect was associated with decrease in fetal weight and delayed ossification. In addition, scapular malformations were observed in four fetuses from three litters. The malformations could have been caused by the same mechanism as holoprosencephaly after early treatment with AY9944. These cholesterol-deficiency-based malformations could have a common cause in the abnormal expression of Hedgehog or other developmental gene proteins, and may thus explain various congenital polymalformative syndromes in humans, including SLOS.

Heterotaxia in a fetus with campomelia, cervical lymphocele, polysplenia, and multicystic dysplastic kidneys: expanding the phenotype of Cumming syndrome

We report on a fetus with tetramelic campomelia, polysplenia, multicystic dysplastic kidneys, and cervical lymphocele. This condition is similar to the autosomal recessive condition described by Cumming et al. [1986: Am J Med Genet 25:783-790] and is different from campomelic syndrome. In addition, our case had anomalies not previously described in this condition, including abnormal lung lobation with bilateral left bronchial morphology, dextrocardia, total anomalous pulmonary venous return, a left superior vena cava, and a right aortic arch. The pancreas was short, with absence of the body and tail. These anomalies are similar to those found in the polyasplenia spectrum. We suggest that the syndrome reported by Cumming et al. may be expanded to include polysplenia with heterotaxia and that Cumming syndrome may be considered another autosomal recessive condition associated with a laterality defect.

New findings in short rib syndrome

This white infant, born at 37 weeks of gestation, had a large cranium, bilateral anophthalmia, a midline cleft lip and palate, hypoplastic chest with short ribs, slightly protuberant abdomen, short limbs, bilateral single transverse palmar creases, a single umbilical artery, normal female external genitalia, normal (46 XY) chromosomes, and radiographic findings suggesting a short-rib (polydactyly) syndrome type IV (Beemer-Langer). Autopsy showed pulmonary hypoplasia, bilateral renal cystic dysplasia, intrahepatic bile duct cysts with periportal fibrosis, pancreatic cysts, absent internal genitalia, an atrophic optic chiasm, absent optic nerves, a single left anterior cerebral artery, polymicrogyria, and fusion of the frontal lobes, preoptic region, mammillary bodies, and thalami.

Familial renal-hepatic-pancreatic dysplasia and Dandy-Walker cyst: a distinct syndrome?

Ivemark et al. first described sibs with renal-hepatic-pancreatic dysplasia (RHPD) (Ivemark BI, Oldfelt V, Zetterström R (1959): Acta Pediatr Scand 48: 1-11). Subsequent reports of affected individuals have described additional malformations and syndromes associated with RHPD. In this paper we describe 2 sibs with RHPD in association with Dandy-Walker cyst (DW). Through an examination of the pattern of associated malformations seen in RHPD we argue that RHPD-DW is a distinct monogenetic syndrome, and not an association.

Thymic-renal-anal-lung dysplasia in sibs: a new autosomal recessive error of early morphogenesis

We report on 3 sisters with a syndrome of unilobed or absent thymus, renal and ureter agenesis/dysgenesis, and intrauterine growth retardation (IUGR). Two of the 3 infants had a unilobed lung and imperforate anus. Recurrence was detected prenatally by the presence of progressive oligohydramnios and IUGR, a unilateral echogenic cystic mass in the renal fossa, and low amniotic fluid disaccharidases in association with an imperforate anus. Several genetic mechanisms can be invoked to explain this occurrence including autosomal recessive inheritance and an unrecognized chromosome imbalance.