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Biomedical subjects

A Giannotti

Publications and source records attributed to A Giannotti.

At least 55 records · Page 3Linked to original sources
PubMed1999

Diagnosis of DiGeorge and Williams syndromes using FISH analysis of peripheral blood smears.

We describe the use of a FISH protocol for detecting chromosome microdeletions in peripheral blood smear leukocytes. This method has the advantage of a smaller sample requirement than classical metaphase chromosome analysis and the potential for analysis of a larger number of chromosome microdeletions using a routine blood smear. A selected series of 10 DiGeorge syndrome (DGS) and 12 Williams-Beuren syndrome (WBS) patients were correctly diagnosed by this method confirming results obtained by molecular cytogenetic metaphases. These results support effectiveness of interphase FISH analysis on peripheral blood smears as a focused, single-step method for the detection of chromosome microdeletions.

Adolescent↗
PubMed1999

Congenital heart diseases in children with Noonan syndrome: An expanded cardiac spectrum with high prevalence of atrioventricular canal.

OBJECTIVE: To report the relative prevalence of various forms of congenital heart disease (CHD) in children with Noonan syndrome (NS) and to describe anatomic characteristics of the subgroup of patients with atrioventricular canal (AVC). STUDY DESIGN: Phenotypic and cardiologic examinations were performed in 136 patients with NS and CHD evaluated at our hospital from January 1986 to December 1998. Cardiac evaluation included chest x-ray film, electrocardiogram, 2-dimensional and color Doppler echocardiography, cardiac catheterization with angiocardiography, and cardiac surgery. RESULTS: The CHDs classically reported in NS, including pulmonary stenosis (39%), hypertrophic cardiomyopathy (10%), atrial septal defect (8%), and tetralogy of Fallot (4%), are well represented in our series; however, aortic coarctation (9%) and anomalies of the mitral valve (6%) may also occur in this syndrome. Moreover, AVC was diagnosed in 21 patients, representing 15% of all CHDs in our series. All patients showed a partial form of AVC, and an associated subaortic stenosis caused by additional anomalies of the mitral valve was detected in 5 of 21 (23.8%) of those patients. CONCLUSION: Left-sided lesions, such as aortic coarctation and anomalies of the mitral valve, are not rare in patients with NS and CHD. Moreover, in this syndrome AVC is quite frequent, the partial form is prevalent, and subaortic stenosis caused by additional anomalies of the mitral valve may be present. This information should be taken into consideration during the cardiologic evaluation of children with NS.

Adolescent↗
PubMed1999

Atypical deletions suggest five 22q11.2 critical regions related to the DiGeorge/velo-cardio-facial syndrome.

Deletions of chromosome 22q11.2 have been associated with distinct phenotypes including DiGeorge syndrome (DGS) and velo-cardio-facial (VCFS) syndrome. These diseases result from a failure to form derivatives of the third and fourth branchial arches during development. DGS/VCFS deletions usually encompass about 3 Mb of genomic DNA in more than 90% of patients. However, deletion mapping studies have failed to demonstrate the existence of a single small region of overlap (SRO) and ruled out any obvious correlation between site or size of deletion and severity of clinical phenotype. We describe three patients carrying 'atypical' deletions presenting the DGS/VCFS phenotype. A comparative analysis of deletions in our patients and those previously published has suggested the existence of five distinct critical regions within the 22q11.2 locus. This observation argues that DGS/VCFS results from haploinsufficiency secondary to a complex and as yet unexplained molecular mechanism, probably involving chromatin effects in mediating gene expression throughout the entire region.

Child, Preschool↗
PubMed1999

The mutational spectrum of the sonic hedgehog gene in holoprosencephaly: SHH mutations cause a significant proportion of autosomal dominant holoprosencephaly.

Holoprosencephaly (HPE) is a common developmental anomaly of the human forebrain and midface where the cerebral hemispheres fail to separate into distinct left and right halves. We have previously reported haploinsufficiency for Sonic Hedgehog ( SHH ) as a cause for HPE. We have now performed mutational analysis of the complete coding region and intron-exon junctions of the SHH gene in 344 unrelated affected individuals. Herein, we describe 13 additional unrelated affected individuals with SHH mutations, including nonsense and missense mutations, deletions and an insertion. These mutations occur throughout the extent of the gene. No specific genotype-phenotype association is evident based on the correlation of the type or position of the mutations. In conjunction with our previous studies, we have identified a total of 23 mutations in 344 unrelated cases of HPE. They account for 14 cases of familial HPE and nine cases of sporadic HPE. Mutations in SHH were detected in 10 of 27 (37%) families showing autosomal dominant transmission of the HPE spectrum, based on structural anomalies. Interestingly, three of the patients with an SHH mutation also had abnormalities in another gene that is expressed during forebrain development. We suggest that the interactions of multiple gene products and/or environmental elements may determine the final phenotypic outcome for a given individual and that variations among these factors may cause the wide variability in the clinical features seen in HPE.

Amino Acid Sequence↗
PubMed1999

Audiological findings in patients with microdeletion 22q11 (di George/velocardiofacial syndrome).

Microdeletion 22q11 (del22q11) is one of the most frequent causes of genetic syndromes. The majority of cases of di George and velocardiofacial syndromes are due to del22q11. These conditions are considered to be developmentally related to neural crest anomalies influencing the differentiation of the branchial arches, including the percursor tissue of the ear. In addition, the UFDIL gene, an ubiquination gene being expressed during embryogenesis in the inner ear primordia, has been identified in the 22q11 critical region. The aim of this study was to evaluate the prevalence of hearing impairment in del22q11 syndrome. Admittance audiometry, behavioural pure tone audiometry and auditory brainstem response (ABR) were performed in 27 children studied at our hospital between 1997 and 1998. Results were related to clinical history, frequency otitis media and immune status. Sensorineural hearing loss was found in 4/27 (15%) patients (severe in three cases, mild in one), conductive hearing impairment in 12/27 (45%) (moderate in four cases, mild in eight) and normal hearing in 11/27 (40%). Interestingly, three of the patients with sensorineural hearing loss had cerebral lesions due to neonatal distress, to hydrocephalus and to post-surgical ischaemia each in one. The prevalence of speech delay, otitis media and low CD3 values was higher among patients with conductive hearing impairment in comparison with those with normal hearing. In conclusion, hearing impairment was documented in 60% of the patients and must be included among the clinical features of del22q11 syndrome. Audiological evaluation is recommended in patients with del22q11 in order to reduce the risk of speech deficit.

Adolescent↗
PubMed1999

Microdeletion 22q11 and oesophageal atresia.

Oesophageal atresia (OA) is a congenital defect associated with additional malformations in 30-70% of the cases. In particular, OA is a component of the VACTERL association. Since some major features of the VACTERL association, including conotruncal heart defect, radial aplasia, and anal atresia, have been found in patients with microdeletion 22q11.2 (del(22q11.2)), we have screened for del(22q11.2) by fluorescent in situ hybridisation (FISH) in 15 syndromic patients with OA. Del(22q11.2) was detected in one of them, presenting with OA, tetralogy of Fallot, anal atresia, neonatal hypocalcaemia, and subtle facial anomalies resembling those of velocardiofacial syndrome. The occurrence of del(22q11.2) in our series of patients with OA is low (1/15), but this chromosomal anomaly should be included among causative factors of malformation complexes with OA. In addition, clinical variability of del(22q11.2) syndrome is further corroborated with inclusion of OA in the list of the findings associated with the deletion.

Anus, Imperforate↗
PubMed1999

Congenital heart defects in patients with DiGeorge/velocardiofacial syndrome and del22q11.

Congenital heart defects (CHDs) are found in 75% of patients with DiGeorge/velocardiofacial (DG/VCF) syndromes with deletion 22q11.2 (del22q11). The purpose of this study was to analyse clinical features and, particularly, types and subtypes of CHDs associated with del22q11 in our series of patients and in those reported in other studies. All patients with CHD and del22q11 present major or minor clinical features of DG/VCF syndrome. Many children, particularly in the neonatal age, have only a "subtle" phenotype, so that accurate phenotypical evaluation is mandatory for selecting patients with CHD at risk for del22q11. Conotruncal cardiac defects are the most common CHDs in patients with DG/VCF syndrome, but other defects can also occur. Peculiar anatomical subtypes are found in patients with del22q11. They are frequently complex, consisting in malalignment with deficiency of the infundibular septum and anomalies of the aortic arch and pulmonary arteries.

Child↗
PubMed1999

Loss of the SHOX gene associated with Leri-Weill dyschondrosteosis in a 45,X male.

A male patient is reported with a 45,X karyotype and Leri-Weill dyschondrosteosis (LWD). FISH analysis with SHOX and SRY gene probes was carried out. One copy of both SHOX and SRY was detected in interphase nuclei, clarifying the origin of LWD and the male phenotype. Molecular results suggested that the 45,X karyotype arose through two independent events. The first occurred at paternal meiosis leading to an unequal crossing over between the short arms of the X and Y chromosomes. As a consequence, the SRY gene was translocated onto Xp, thereby explaining the male phenotype of the patient. The second event probably occurred at maternal meiosis or at the early stages of the zygote resulting in the loss of the maternal X chromosome.

Adolescent↗
PubMed1999

Detection of an atypical 7q11.23 deletion in Williams syndrome patients which does not include the STX1A and FZD3 genes.

We present two patients with the full Williams syndrome (WS) phenotype carrying a smaller deletion than typically observed. The deleted region spans from the elastin gene to marker D7S1870. This observation narrows the minimal region of deletion in WS and suggests that the syntaxin 1A and frizzled genes are not responsible for the major features of this developmental disorder and provides important insight into understanding the genotype-phenotype correlation in WS.

Antigens, Surface↗
PubMed1998

Congenital heart defect in sibs with discordant karyotypes.

Congenital heart defects (CHDs) are genetically heterogeneous, associated with a variety of genetic conditions. Familial aggregation of CHD in patients with and without Down syndrome is rare. We report on the occurrence of concordant CHD in three sets of sibs with discordant karyotypes. In the first family, atrioventricular canal (AVC) was diagnosed in a chromosomally normal child and in his brother with Down syndrome. In the second family, AVC was associated with trisomy 21 in one sib and with trisomy 18 in the other. In the third family, tetralogy of Fallot was present in one patient with Down syndrome and in his nonsyndromic sister. Although the genetic heterogeneity of Down and non-Down CHD is not disputed, a susceptibility to both euploid and aneuploid CHDs could exist, and common predisposing factors could play a role in both conditions.

Down Syndrome↗
PubMed1998

Noonan syndrome and aortic coarctation.

Congenital heart defect (CHD) is present in half of the propositi with Noonan syndrome (NS). Aortic coarctation (AC) is rarely seen in NS, since only three male patients with NS and AC have been previously reported. On the other hand, AC is common in the Ull-rich-Turner syndrome, an aneuploidy disorder and not a mendelian syndrome. In order to evaluate if AC is truly rare in patients with NS, we reviewed our series of 184 propositi with NS and CHD. AC was diagnosed in 16 (8.7%) patients. There were 11 males and 5 females. All had normal chromosomes. Clinical characteristics of the patients are described. Familial occurrence was detected in one girl with NS and AC whose mother and sibs also had NS, but different form of CHDs. Thus, AC is more frequent in NS than previously reported.

Adolescent↗
PubMed1997

Intrafamilial variability of Pfeiffer-type cardiocranial syndrome.

We report on the occurrence of Pfeiffer-type cardiocranial syndrome in a brother and sister born to unaffected parents. The cardinal manifestations of the syndrome are congenital heart defect, sagittal craniosynostosis, genital anomalies, and mental and growth retardation. The craniosynostosis was present in only one of the sibs, suggesting intrafamilial variability of the syndrome. The clinical spectrum of cardiocranial syndrome is further expanded by the inclusion of renal, joint, and palpebral abnormalities detected in our patients. The occurrence of the syndrome in a brother-sister sib pair supports the hypothesis of an autosomal-recessive inheritance.

Adult↗
PubMed1997

Progeroid syndrome with characteristic facial appearance and hand anomalies in father and son.

We report on the father-to-son transmission of a progeroid syndrome characterized by facial anomalies, sparse subcutaneous fat, and hand anomalies including syndactyly, camptodactyly, and finger deviation. Mild mental retardation, microcephaly, and congenital heart defect were found only in the son. To our knowledge, this syndrome has not been described previously.

Abnormalities, Multiple↗