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Biomedical subjects

G Novelli

Publications and source records attributed to G Novelli.

At least 109 records · Page 6Linked to original sources

Non-invasive early prenatal molecular diagnosis using retrieved transcervical trophoblast cells.

Fetal DNA was recovered from 17 of 39 (44%) transcervical cell (TCC) samples obtained between 7 and 9 weeks of gestation by endocervical canal flushing. Trophoblast retrieval was adequate for polymerase chain reaction (PCR) amplification of Y chromosome-specific DNA sequences and detection of paternal-specific microsatellite alleles. The fetal sex predicted by PCR in TCCs was confirmed in all cases by karyotype analysis of chorionic villi at 10 weeks of gestation. The absence of the disease-associated paternal alleles in TCC samples from two pregnancies at risk for spinal muscular atrophy and myotonic dystrophy predicted unaffected fetuses in agreement with subsequent results on chorionic villi and newborns' leukocytes. A trisomy 21 fetus was diagnosed in TCCs using fluorescent in situ hybridization (FISH) and semi-quantitative PCR analysis of superoxide dismutase-1 (SOD 1). Present experience indicates that TCC sampling is a promising technique for early prenatal monitoring of Mendelian disorders and chromosome aneuploidy.

Adult↗

Diagnosis of DiGeorge syndrome in nuclei released from archival autoptic heart specimens using fluorescence in situ hybridization.

Seven formalin-fixed, paraffin-embedded heart specimens set up at autopsy performed from 3 to 18 years before analysis of newborns in which DiGeorge syndrome (DGS) was suspected were evaluated by fluorescence in situ hybridization (FISH) using a DGS region-specific probe and a control probe on nuclei released from thick sections. The diagnosis was confirmed in four of the six specimens, which provided valuable results, and in none of the controls. This study supports the feasibility and usefulness of FISH genotyping of archival autoptic material, which improves and assists the counselling procedures.

Autopsy↗

Detection of eight beta-thalassemia mutations using a DNA enzyme immunoassay.

We describe the use of a polymerase chain reaction-based method followed by a DNA enzyme immunoassay for the simultaneous detection of the eight most common beta-thalassemia mutations in the Mediterranean population. The method is specific, sensitive, and easily applicable in routine clinical laboratories for the molecular diagnosis of beta-thalassemia patients and at risk couples.

Alleles↗

Discordant clinical outcome in type III spinal muscular atrophy sibships showing the same deletion pattern.

Three type III spinal muscular atrophy (SMA) families are described in which the same deletion pattern for SMN gene and flanking loci is apparent in both affected and unaffected siblings. Deletions extending to include the NAIP gene are reported in one sibship. All three individuals in which SMN and/or NAIP deletions were detected showed the same haplotypes for SMA linked microsatellite markers as their affected sibs. The three index cases had a SMA III with early onset (1.5-2 yr) and became chairbound at the age 4, 5 and 20 yr. The three haploidentical sibs were given a clinical severity score. One of them showed no sign of the disease at the age of 4 yr and was considered "unaffected"; a 35-yr-old female, who had no symptoms but showed tongue fasciculations and hand tremor was considered "asymptomatic"; a 34-yr-old female, who had mild muscular weakness since the age of 24, was rated "mild". These observations demonstrate the presence of a continuum of clinical variability within SMA III families. These data suggest that, in these three families at least, the SMA phenotype is caused or influenced by another gene(s) additional to SMN.

Adult↗

cDNA characterization and chromosomal mapping of two human homologues of the Drosophila dishevelled polarity gene.

The Drosophila dishevelled gene (dsh) encodes a secreted glycoprotein, which regulates cell proliferation, acting as a transducer molecule for developmental processes, including segmentation and neuroblast specification. We have isolated and characterized cDNA clones from two different human dsh-homologous genes, designated as DVL-1 and DVL-3. DVL-1 and DVL-3 putative protein products show 64% amino acid identity. The DVL-1 product is 50% identical to dsh and 92% to a murine dsh homologue (Dvl-1). Both human DVL genes are widely expressed in fetal and adult tissues, including brain, lung, kidney, skeletal muscle and heart. DVL-1 locus maps to chromosome 1p36 and DVL-3 to chromosome 3q27. DVL-1 locus on chromosome 1 corresponds to the murine syntenic region where Dvl-1 is located. DVL-1 and DVL-3 are members of a human dsh-like gene family, which is probably involved in human development. Although the precise role of these genes in embryogenesis is only conjectural at present, the structural and evolutionary characteristics suggest that mutations at their loci may be involved in neural and heart developmental defects.

Adaptor Proteins, Signal Transducing↗

Correlation of SfiI macrorestriction endonuclease fingerprint analysis of Candida parapsilosis isolates with source of isolation.

SfiI macrorestriction digests from whole chromosome DNA preparations of 46 isolates of Candida parapsilosis from vaginal (20 isolates), blood (23 isolates) and soil (three isolates) sources were examined by CHEF-MAPPER pulsed-field electrophoresis. The isolates were grouped into nine macrorestriction endonuclease fingerprint (MEF) classes according to the number or size of the macrorestriction fragments, or both. The electrophoretic karyotype (EK) was also examined and found to contain 18 karyotypic classes (named A-R). A comparison between SfiI MEF and EK demonstrated that the former correlated much better than the latter with the source of C. parapsilosis isolates. Five SfiI classes (I-V) contained only vaginal isolates (or vaginal and three soil isolates, class I), and the blood isolates were distributed between four classes (VI-IX). This relationship was less evident with the EK classes as several of these were composed of both vaginal and blood isolates (B, G, L and M). The three soil isolates were in class A which also included one vaginal isolate. We conclude that SfiI macrorestriction endonuclease patterns seem to be useful in discriminating among C. parapsilosis isolates, with apparent association with source of isolation.

Blood↗

Human homologue sequences to the Drosophila dishevelled segment-polarity gene are deleted in the DiGeorge syndrome.

DiGeorge syndrome (DGS) is a developmental defect of some of the neural crest derivatives. Most DGS patients show haploinsufficiency due to interstitial deletions of the proximal long arm of chromosome 22. Deletions of 22q11 have also been reported with patients with the velocardio-facial syndrome and familial conotruncal heart defects. It has been suggested that the wide phenotype spectrum associated with 22q11 monosomy is a consequence of contiguous-gene deletions. We report the isolation of human cDNAs homologous to the Drosophila dishevelled (dsh) segment-polarity gene. Sequences homologous to the 3' UTR of these transcripts (DVL-22) were positioned within the DGS critical region and were found to be deleted in DGS patients. Human DVL mRNAs are expressed in several fetal and adult tissues, including the thymus and, at high levels, the heart. Two transcripts, 3.2 and 5kb, were detected, in northern blot analysis, with different expression patterns in the surveyed tissues when different cDNAs were used. The isolated cDNAs exhibit high amino acid homology with the mouse and Xenopus Dvl-1 gene, the only other vertebrate dsh homologues so far isolated. The pivotal role of dsh in fly development suggests an analogous key function in vertebrate embryogenesis of its homologue genes. Since DGS may be due to perturbation of differentiation mechanisms at decisive embryological stages, a Dsh-like gene in the small-region overlap (SRO) might be a candidate for the pathogenesis of this disorder.

Adaptor Proteins, Signal Transducing↗

[Genetic aspects of deafness].

Congenital sensorineural hearing impairment affects approximately 1 in 1000-2000 children and is of genetic origin in at least one half of these cases. Over 70% of congenital sensorineural hearing impairment is non-syndromic while, about 30% is associated with other defects. Over 75% of congenital non-syndromic hearing sensorineural hearing impairment is autosomal recessive and to date at lest ten loci have been implicated. The remaining forms are transmitted in an autosomal dominant, or X-linked (2%) manner. Some congenital types of hearing impairment are also due to chromosomal aneuploides or mitochondrial DNA mutations. Although different loci associated with hearing impairment have been mapped to specific chromosomic regions, the cloning and the functional characterization of these genes is not immediate.

Aneuploidy↗

Different expression of the myotonin protein kinase gene in discrete areas of human brain.

We have examined the myotonin protein kinase (MT-PK) gene expression in different human brain areas. Four different spliced forms, comprising exons 13 and 14, were identified and characterized. One form (MYOT-A), lacking the entire exon 13, had not been detected in other studies and it is likely to be a brain-specific transcript. Different brain areas show a specific transcription pattern. These results suggest that MT-PK may have specialized functions in different areas of central nervous system. Alterations of this complex expression pattern could be responsible for the mental status impairment observed in myotonic dystrophy patients.

Alternative Splicing↗