Comparison of occurrence of genetic syndromes in ventricular septal defect with pulmonic stenosis (classic tetralogy of Fallot) versus ventricular septal defect with pulmonic atresia

Our results confirm that classic TF can be associated with many genetic conditions, but most patients are nonsyndromic. In contrast, children with TF-PA have a high incidence of genetic syndromes, particularly those related to CATCH22 syndrome.

Orocardiodigital syndrome: an oral-facial-digital type II variant associated with atrioventricular canal

We report on a patient with a constellation of anomalies including hamartomas of the tongue, polysyndactyly, and atrioventricular canal. A similar association has been previously described by Orstavik et al in two sibs. The clinical spectrum of the oralfacial-digital syndrome (OFDS) type II includes all these features. In particular, congenital heart defect, mainly atrioventricular canal, has been described in a few cases. It has been previously suggested that these latter patients may be affected by a variant of OFDS type II. We propose to distinguish this orocardiodigital variant and point out the association of the syndrome with atrioventricular canal.

The search for hemizygosity at 22qll in patients with isolated cleft palate

The striking association between oral clefting and the velocardio-facial syndrome (VCFS), a common disorder pathogenetically related to 22q11 deficiency, has prompted the search for this deletion in a group of patients with isolated cleft palate. (CP). Thirty-three patients with posterior CP and 5 with complete CP were included in this study, together with 12 patients with a clinical diagnosis of VCFS. Standard and high resolution chromosome analysis was performed, providing normal results. Southern blotting followed by densitometric analysis and fluorescent in situ hydridization of region 22q11 showed no single case of deletion among the isolated CP patients, while deficiency was found in 10 of 12 VCFS patients. These results demonstrate that hemizygosity at 22q11 is not increased in isolated CP.

Associated cardiac anomalies in isolated and syndromic patients with tetralogy of Fallot

To detect in children with tetralogy of Fallot (ToF) the prevalence of associated cardiac anomalies in syndromic and isolated cases, the additional cardiac defects of 150 consecutive patients with ToF (102 isolated and 48 syndromic cases) were evaluated by review of echocardiographic, angiocardiographic, and surgical reports. Syndromic patients were classified into groups with branchial arch defects, Down syndrome, and other genetic conditions. ToF is significantly associated with additional cardiac malformations in patients with branchial arch (11 of 21, p <0.01) and Down (10 of 20, p <0.0001) syndromes. The subarterial ventricular septal defect with deficiency of the infundibular septum (4 of 21, p <0.01) and the right aortic arch (6 of 21, p <0.05) were prevalent in patients with branchial arch syndromes, whereas atrioventricular canal (10 of 20, p <0.0001) was associated with ToF in patients with Down syndrome. Peculiar anatomic cardiac patterns are present in children with ToF and may alert the cardiologist to look at additional cardiac anomalies. Moreover, the presence of some associated cardiac anomalies may suggest careful clinical evaluation for genetic syndromes.

Noonan syndrome: structural abnormalities of the mitral valve causing subaortic obstruction

Among 41 consecutive children with classic Noonan syndrome, 27 patients (66%) presented cardiac anomalies. Eight patients (19.5%) had a congenital anomaly of the mitral valve consisting of 5 with partial atrioventricular canal defect and 3 with anomalous insertion of the mitral valve on the ventricular septum. Five patients (12%) presented with a significant left ventricular outflow tract obstruction caused by the anterior leaflet of the mitral valve: two cases with atrioventricular canal and three cases with isolated anomalous insertion of the mitral valve. Echocardiography is the best tool for the diagnosis. Cardiac defects of patients with Noonan syndrome may be explained on the basis of anomalies of the extracellular matrix involving cardiac valves including the mitral valve.

CONCLUSION

In children with Noonan syndrome and left ventricular hypertrophy a careful echocardiographic assessment of the mitral valve should reveal those in whom the left ventricular outflow tract obstruction is anatomical in nature.

Sporadic trichodental dysplasia with microcephaly and mental retardation

Trichodental syndrome is a rare autosomal dominant ectodermal dysplasia. Hair and dental anomalies have been found in different combinations in most affected persons in three families. The features of trichodental syndrome were observed in a young female in which sparse, fine, lustreless and slow growing hairs were associated with bigeminismus of inferior lateral incisors. Ultrastructural hair analysis showed consistent variation in contour of the shaft and reduced to absent cuticular scale. Distinguishing features in this patient were microcephaly and mild mental retardation.

Joint dislocation and cerebral anomalies are consistently associated with oral-facial-digital syndrome type IV

We present a female patient with the oral-facial-digital syndrome type IV. Our report, the tenth in the literature, describes the typical manifestations of the syndrome, combined with malformations and deformations which have not always been described in the previously reported cases. They include cerebral and renal anomalies, anal atresia and dislocation of elbows and knees.

Two pedigrees of autosomal dominant atrioventricular canal defect (AVCD): exclusion from the critical region on 8p

Atrioventricular canal defects (AVCD) constitute the predominant congenital heart defect in Down syndrome. For this reason, a candidate gene involved in atrioventricular canal development was previously searched and excluded in dominant pedigrees of AVCD, using linkage analysis of polymorphisms from chromosome 21. Because of the striking association between 8p deletion and AVCD, a search for an AVCD gene was carried out in two pedigrees of individuals with autosomal dominant AVCD using a set of DNA markers of the 8pter-->q12 region. These two families include affected individuals and subjects who have transmitted the defect but are not clinically affected. Two-point lod scores were significantly negative for all markers at penetrance levels of 90% and 50%. Multipoint analysis excluded the region covered by the markers LPL-D8S262 and 30 cM to either side of this area. This result corroborates heterogeneity of this heart defect and indicates that the genetic basis of familial AVCD is different from AVCD associated to either trisomy 21 or 8p deletion.

22q11 deletions in isolated and syndromic patients with tetralogy of Fallot

Tetralogy of Fallot (TF) is a congenital conotruncal heart defect commonly found in DiGeorge (DGS) and velo-cardio-facial (VCFS) syndromes. The deletion of chromosome 22q11 (del22q11) is a well established cause of DGS and VCFS, and it has been demonstrated also in sporadic or familial cases of TF. In order to investigate the prevalence of del22q11 in patients with TF, we analyzed the DNA of 137 consecutive patients with syndromic and isolated TF, using the HD7k probe, which detects hemizygosity for the D22S134 locus. Del22q11 has been detected in 11/26 (42%) syndromic patients. Evidence for hemizygosity was obtained in all patients with DGS and in 8/15 patients with VCFS. None of the 107 patients with isolated TF had del22q11. Our experience suggests that children with TF and del22q11 always present major or minor extracardiac anomalies. These features, including subtle facial dysmorphisms, should be checked routinely in patients with TF and other conotruncal heart defects.

An autosomal recessive syndrome of cleft palate, cardiac defect, genital anomalies, and ectrodactyly (CCGE)

We report a brother and sister affected by a constellation of malformations, including cleft palate, cardiac defect, genital anomalies, and ectrodactyly (CCGE). A similar association has been reported previously by Richieri-Costa and Orquizas in a male patient born to consanguineous parents. An autosomal recessive pattern of inheritance is proposed for this syndrome.

Determination of a new collagen type I alpha 2 gene point mutation which causes a Gly640 Cys substitution in osteogenesis imperfecta and prenatal diagnosis by DNA hybridisation

The molecular defect responsible for a sporadic case of extremely severe (type II/III) osteogenesis imperfecta was investigated. The mutation site was localised in the collagen type I pro alpha 2 mRNA molecules produced by the proband's skin fibroblasts by chemical cleavage of mismatch in heteroduplex nucleic acids. Reverse transcription-polymerase chain reaction DNA amplification, followed by cloning and sequencing, showed heterozygosity for a G to T transversion in the first nucleotide of exon 37 of the COL1A2 gene, which led to a cysteine for glycine substitution at position 640 of the triple helical domain. This newly characterised mutation is localised in a domain which contains several milder mutations, confirming that glycine substitutions within the alpha 2(I) chain do not follow a linear gradient pattern for genotype to phenotype correlations. In a subsequent pregnancy, absence of the G2327T mutation in the fetus was shown by allele specific oligonucleotide hybridisation to the trophoblast derived fibroblast mRNA after reverse transcription and in vitro amplification. (The nucleotide number assigned to the mutant base was inferred from the numbering system devised by the Osteogenesis Imperfecta Analysis Consortium (The OIAC Newsletter, 1 April 1994).)