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Biomedical subjects

A Giannotti

Publications and source records attributed to A Giannotti.

At least 91 records · Page 5Linked to original sources
PubMed1995

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.

Child↗
PubMed1995

Analysis of the elastin gene in 60 patients with clinical diagnosis of Williams syndrome.

Williams syndrome (WS) is caused by deletion of the elastin (ELN) gene. We have analyzed an intragenic restriction fragment length polymorphism (RFLP) and the gene dosage of ELN using a new probe (FP4) in a series of 60 sporadic patients with a clinical diagnosis of WS. Deletion of the ELN gene was shown in 54 cases, while clinical revaluation of the 6 patients without the deletion did not confirm the diagnosis of WS. These results support the genetic homogeneity of WS, and the high accuracy of ELN molecular analysis, which can be confidenty used for providing genetic counselling to WS families.

Adolescent↗
PubMed1995

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.

Adolescent↗
PubMed1995

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

UNLABELLED: 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.

Adolescent↗
PubMed1995

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.

Child, Preschool↗
PubMed1995

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.

Abnormalities, Multiple↗
PubMed1995

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.

Abnormalities, Multiple↗
PubMed1994

Congenital cardiac defect in a patient with mosaic 45,X/46,XX,i(21q) karyotype.

A baby is described with 45,X/46,XX,i(21q) mosaicism. DNA analysis indicated that the abnormality arose from two independent postzygotic mutations in a 46,XX zygote, involving the paternal chromosomes 21 and X. In agreement with previous reports, most of the clinical dysmorphisms observed were consistent with Down syndrome. Moreover, congenital heart disease consisted of an atrioventricular canal associated with slight hypoplasia of the left ventricle and a mitral anulus, a complex defect including features found in both Down and Turner syndromes.

Chromosome Aberrations↗
PubMed1994

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).)

Base Sequence↗
PubMed1994

Trisomy 8 syndrome owing to isodicentric 8p chromosomes: regional assignment of a presumptive gene involved in corpus callosum development.

Two patients with trisomy 8 syndrome owing to an isodicentric 8p;8p chromosome are described. Case 1 had a 46,XX/46,XX,-8,+idic(8)(p23) karyotype while case 2, a male, had the same abnormal karyotype without evidence of mosaicism. In situ hybridisation, performed in case 1, showed that the isochromosome was asymmetrical. Agenesis of the corpus callosum (ACC), which is a feature of trisomy 8 syndrome, was found in both patients. Although ACC is associated with aneuploidies for different chromosomes, a review of published reports indicates that, when associated with chromosome 8, this defect is the result of duplication of a gene located within 8p21-pter. Molecular analysis in one of our patients led us to exclude the distal 23 Mb of 8p from this ACC region.

Abnormalities, Multiple↗
PubMed1994

[In situ ++hybridization with painting probes in the definition of reciprocal translocations].

Standard banding cytogenetic techniques do not always allow to define the size of chromosome rearrangements involving reciprocal translocations. Fluorescent in situ hybridization of chromosome-specific libreries allowed the rapid and unequivocal characterization of three chromosome rearrangements: a reciprocal translocation involving chromosome 11 and 22, an other involving chromosome 5 and 16 and at least a rearrangement involving chromosomes 5 and 11.

Adult↗