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Biomedical subjects

B Dallapiccola

Publications and source records attributed to B Dallapiccola.

At least 109 records · Page 6Linked to original sources
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

Searching for psoriasis susceptibility genes in Italy: genome scan and evidence for a new locus on chromosome 1.

Psoriasis is a chronic inflammatory dermatitis, affecting approximately 2% of the population. Major clinical features include red, scaly patches on scalp, elbows, and knees, with or without severe arthritis. Several putative susceptibility loci have been mapped by parametric and non-parametric linkage analysis to chromosome regions 2p, 4q, 6p, 8q, 16q, 17q, and 20p; however, the most significant results and confirmation of linkage are only available for the 17q and 6p chromosome regions at present. In this study, 22 multiplex Italian families were investigated for linkage to 6p and 17q susceptibility regions, using a set of four microsatellites. These analyses failed to detect significant linkage with any of the examined markers. A genome-wide scan was then performed on one of the largest pedigrees, searching for an additional susceptibility locus. This study disclosed a putative linkage to chromosome 1cen-q21 markers. When these microsatellites were analyzed in the remaining families of the sample, a significant linkage was observed using both parametric and non-parametric methods. The highest two-point lod score value was obtained with D1S305 marker (3.75 at 0 = 0.05). Non-parametric analysis at this locus also demonstrated a significant excess of allele sharing (p = 0.0001).

Chromosome Mapping↗
PubMed1999

Cellular uptake and delivery monitoring of liposome/DNA complexes during in vitro transfection of CFTR gene.

The cellular uptake and distribution of cationic liposomes Dc-Chol/DOPECFTR gene complexes were assessed by electronic and confocal laser scanner microscopy (CLSM) for the CFTR gene transfer to human adenocarcinoma and tracheal epithelial cell lines. Cationic lipid forms unilamellar and multilamellar vesicles capable of rapid and efficient transport of gene into target cells. The number of fluorescent complexes was increasing with time in cells up to 6 hours showing a punctate and homogeneous DNA distribution in the cytoplasmatic and nuclear compartments, including the nucleolus. No significant difference in the biochemical and cellular behavior was observed between the investigated system and other systems previously tested. This study adds new insights into the CFTR cationic liposome-mediated gene delivery.

Cell Line↗
PubMed1999

Localization of a gene for familial patella aplasia-hypoplasia (PTLAH) to chromosome 17q21-22.

Patella aplasia-hypoplasia (PTLAH) is a rare genetic defect characterized by congenital absence or marked reduction of the patella. PTLAH can occur either as an isolated defect or in association with other malformations, and it characteristically occurs in the nail-patella syndrome and in some chromosome imbalances. We report the first evidence of linkage for isolated PTLAH in an extended Venezuelan family. After exclusion of the candidate chromosome regions where disorders associated with PTLAH have been mapped, a genomewide scan was performed that supported mapping of the disease locus within a region of 12 cM on chromosome 17q22. Two marker loci (D17S787 and D17S1604) typed from this region gave maximum LOD scores >3. Accordingly, multipoint analysis gave a maximum LOD score of 3.39, with a most likely location for the disease gene between D17S787 and D17S1604. Sequencing of the noggin gene, a candidate mapping between these markers, failed to reveal any mutation in affected subjects.

Adolescent↗
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

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↗
PubMed1998

Structure and expression of the human ubiquitin fusion-degradation gene (UFD1L).

We report the genomic organization, RNA and protein expression patterns of the gene encoding for the human homolog of the yeast ubiquitin fusion-degradation protein-1 (UFD1L). This enzyme is involved in a ubiquitin-dependent proteolytic pathway (UFD), firstly described in yeast. The human UFD1L gene is organized into 12 exons ranging in size from 33 to 161 bp. Sequence analysis of the 5'-flanking region of the gene revealed a high GC content, multiple CCAAT-binding motifs, CREB, CFT, and AP-2 sites. RNA transcripts were detected in all tissues and cell lines examined, including thymus, thymocytes, T- and B-cells, fibroblasts, chorionic villi, and amniocytes. In Western blot, the UFD1L antibody demonstrated the presence of multiple protein isoforms in all the tested tissues. Expression profile and promoter characteristics suggest UFD1L is a housekeeping gene with implications in the pathogenesis of DiGeorge/velo-cardio-facial syndrome, due to 22q11.2 deletions.

Adaptor Proteins, Vesicular Transport↗