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Biomedical subjects

Bruno Dallapiccola

Publications and source records attributed to Bruno Dallapiccola.

At least 73 records · Page 4Linked to original sources
PubMed2005

ZFPM2/FOG2 and HEY2 genes analysis in nonsyndromic tricuspid atresia.

Tricuspid atresia (TriAt), the third most common cyanotic congenital heart defect (CHD), consists of complete lack of tricuspid valve formation, with no connection between the right atrium and the right ventricle. To date, the genetic mechanism responsible of TriAt is still obscure. However, animal models have suggested a role of cardiogenic Zfpm2/Fog2 and Hey2 genes in the pathogenesis of TriAt. Therefore, we screened 40 individuals affected by nonsyndromic TriAt for ZFPM2/FOG2 and HEY2 gene mutations. No pathogenetic mutation has been identified, thus failing to demonstrate a major role of ZFPM2/FOG2 and HEY2 genes in the pathogenesis of human TriAt.

Adolescent↗
PubMed2005

Distinguishing the four genetic causes of Jouberts syndrome-related disorders.

Jouberts syndrome-related disorders are a group of recessively inherited conditions showing cerebellar vermis hypoplasia and the molar tooth sign of the midbrain-hindbrain junction. Recent analyses have suggested at least three loci, JBTS1 (9q34.3), -2 (11p11.2-q12.3), and -3 (6q23), but the phenotypic spectrum associated with each locus has not been delineated. In addition, deletions of the NPHP1 gene, usually responsible for isolated juvenile nephronophthisis, are occasionally encountered among Jouberts syndrome-related disorder patients. Here, we describe four novel families showing evidence of linkage to two of these loci, provide a 3.6Mb refinement of the JBTS2 locus, and perform a detailed comparison of all linked families identified so far, to define the clinical and radiographical hallmarks for each genetic condition. We find that JBTS1 and -3 primarily show features restricted to the central nervous system, with JBTS1 showing largely pure cerebellar and midbrain-hindbrain junction involvement, and JBTS3 displaying cerebellar, midbrain-hindbrain junction, and cerebral cortical features, most notably polymicrogyria. Conversely, JBTS2 is associated with multiorgan involvement of kidney, retina, and liver, in addition to the central nervous system features, and results in extreme phenotypic variability. This provides a useful framework for genetic testing strategies and prediction of which patients are most likely to experience development of systemic complications.

Abnormalities, Multiple↗
PubMed2005

Novel EXT1 and EXT2 mutations identified by DHPLC in Italian patients with multiple osteochondromas.

We describe the results of an optimised DHPLC-based mutation screening of the EXT1 and EXT2 genes in Italian patients affected by multiple osteochondromas [MO; also referred to as hereditary multiple exostoses (HME) in the literature], using a multistep approach. We first analysed 36 unrelated probands for EXT1 mutations by DHPLC analysis and subsequent direct sequencing of all samples with abnormal elution profile. Negative cases were then screened for EXT2 mutations using the same approach. In patients who tested normal at DHPLC screening, all EXT1 and EXT2 exons and splice-site junctions were directly sequenced. In 7 informative families, we also performed a pre-screening linkage analysis to selectively focus the DHPLC testing on the EXT1 or EXT2 gene. We detected 31 MO-related mutations, of which 23 (74%) were novel. Seven polymorphisms were also found. Twenty-four mutations (77%) were found in EXT1 and 7 (23%) in EXT2. No disease-causing mutations were detected in five of 36 patients, with a mutation frequency of 86%. According with previous studies, most mutations (90%) are loss of function. Neither false positive nor false negative results were obtained. This multistep method can be considered a fast and reliable diagnostic strategy for the detection of EXT1/2 mutations, with excellent sensitivity and specificity.

Alternative Splicing↗
PubMed2005

A novel family with an unusual early-onset generalized dystonia.

We report on an Italian family in which three brothers and their maternal grandfather had a generalized early-onset dystonia with mild parkinsonian signs. Genetic testing excluded the rapid-onset dystonia-parkinsonism locus (DYT12; OMIM*128235), autosomal recessive Parkin locus (PARK2; OMIM *602544), and DYT1 dystonia. Three affected siblings were found to share an identical haplotype at the X-linked dystonia-parkinsonism locus (XDP; Lubag; OMIM*314250). This haplotype differed from the haplotype observed in Filipino patients, ruling out the hypothesis of a common underlying mutation. In addition, direct sequencing analysis of the putative disease causing changes observed in Filipino patients were not found in the Italian patients. The condition we describe could be a newly recognized dystonia syndrome with parkinsonism.

Adult↗
PubMed2005

Reproductive history of a healthy woman with mosaic duplication of chromosome 4p.

OBJECTIVES: Mosaic autosomal duplications are rare and often result in mental retardation and congenital anomalies. Phenotype is not predictable depending on the chromosomal imbalance involved and the percentage and tissues distribution of unbalanced cells. We report on a young woman carrying a mosaic duplication of chromosome 4p, evaluated because of three abortions due to IUGR and fetal malformation. METHODS: Mosaic dup(4p) was detected by standard and molecular cytogenetics. RESULTS: Unbalanced cells accounted for about 20 to 30% of nuclei in four examined tissues and did not cause any obvious phenotypic effect. CONCLUSION: It is likely that mosaic duplications are underascertained because they are not associated with obvious clinical effects in some individuals. Prenatal diagnosis is the method of choice to predict the karyotype in the offspring of subjects carrying mosaic chromosome imbalances.

Abortion, Spontaneous↗
PubMed2005

Cutis laxa in Kabuki make-up syndrome.

Kabuki make-up syndrome (KMS; OMIM#147920) is a multiple congenital anomalies/mental retardation syndrome of unknown cause, first described independently by Niikawa and Kuroki. It is characterized by a peculiar facial appearance, mild to moderate mental retardation, skeletal abnormality, joint laxity, short stature, and unusual dermatoglyphic patterns. Several additional malformations (eg, cleft palate), cardiovascular defects, genitourinary and gastrointestinal tract anomalies, otologic and ophthalmologic abnormalities, and recurrent infections are also frequently present. It is mostly sporadic, although some familial cases have been reported. Inheritance is thought to be autosomal dominant or X-linked recessive; several chromosomal abnormalities have been found, but none of them seems to be specific to KMS. The fact that the majority of patients are sporadic and show a wide spectrum of clinical features rules out the hypothesis that KMS is a condition with a microdeletion involving several contiguous genes. We recently observed an Italian boy with typical KMS associated with cutis laxa, which, to our knowledge, is an uncommon finding in KMS, never reported in more than 350 KMS cases previously described in the literature.

Abnormalities, Multiple↗
PubMed2005

Screening of mutations in the CFTR gene in 1195 couples entering assisted reproduction technique programs.

Genetic testing of the cystic fibrosis transmembrane conductance (CFTR) gene is currently performed in couples undergoing assisted reproduction techniques (ART), because of the high prevalence of healthy carriers in the population and the pathogenic relationship with congenital bilateral absence of vas deferens (CBAVD). However, discordant data have been reported concerning the usefulness of this genetic test in couples with no family history of cystic fibrosis (CF). In this study, we report the results of CFTR molecular screening in 1195 couples entering ART. Genetic testing was initially carried out in a single partner of each couple. CFTR mutations were detected in 55 subjects (4.6%), a percentage that overlaps with the one reported in the general population. However, significantly higher frequencies of were found in CBAVD individuals (37.5%) and in males with nonobstructive azoospermia (6.6%). The 5T allele was found in 78 patients (6.5%). This figure was again significantly different in males with nonobstructive-azoospermia (9.9%) and in those with CBAVD (100%). All together, 139 subjects (11.6%) had either a CFTR mutation or the 5T allele. Subsequent molecular analysis of their partners disclosed a CFTR mutation or 5T allele in nine cases (6.5%). However, none of these couples had CFTR alterations in both members, a CFTR mutation being invariably present in one partner and the 5T allele in the other. In order to improve genetic counselling of these couples, the TG-M470V-5T association was analyzed, and a statistically significant relationship between 12TG-V470 and CBAVD was detected.

Alleles↗
PubMed2005

Erythrocytes-mediated delivery of dexamethasone in steroid-dependent IBD patients-a pilot uncontrolled study.

BACKGROUND AND AIM: Autologous erythrocytes can be used as carriers of drugs, owing to the ability of their membrane to be opened and resealed under appropriate conditions. In this pilot uncontrolled study, we investigated efficacy and safety of dexamethasone-encapsulated erythrocytes in steroid-dependent IBD patients. MATERIALS AND METHODS: Ten patients (5 with ulcerative colitis and 5 with Crohn's disease) with steroid dependency ranging from 8 to 60 months were studied. Seven of them were in clinical remission, and the remaining three had mild activity. Eight patients were also under azathioprine or 6-MP for at least 6 months (range 6-24 months), while another two patients were intolerant to both drugs. Fifty milliliters of blood were drawn from each subject; dexamethasone 21-Phosphate (Dex 21-P) was encapsulated into erythrocytes by means of specially designed equipment, and drug-loaded erythrocytes were infused into original donors. The procedure was repeated after 4 and 8 wk, and patients were instructed to withdraw corticosteroids. RESULTS: A mean dose of 5.5+/-2.4 mg Dex 21-P was loaded in the erythrocytes at each treatment. Following re-infusion of loaded erythrocytes, plasma Dexamethasone (Dex) concentrations were detected after as long as 28 days. Steroids were completely withdrawn by the second month. After the third infusion, all patients, including the three with mild active disease, were in clinical remission. ESR levels dropped from 47+/-27 at baseline to 27+/-16 mm/h (p<0.02), and CRP levels from 1.6+/-1.3 to 0.6+/-0.5 mg/dl (p<0.02). After a mean follow-up of 12+/-3 months, six patients relapsed, and the remaining four patients remained in remission. Pre-existing steroid-related adverse effects disappeared during the follow-up. CONCLUSIONS: Loading of Dex 21-P in autologous erythrocytes is feasible and safe. The very low dose of Dex released in blood stream was able to maintain patients in clinical remission and allowed steroids withdrawal.

Adult↗
PubMed2005

A novel locus for autosomal dominant cone and cone-rod dystrophies maps to the 6p gene cluster of retinal dystrophies.

PURPOSE: To characterize clinically and genetically a four-generation Italian family with autosomal dominant retinal dystrophy. METHODS: Thirty-seven family members underwent a detailed ophthalmologic investigation, comprising visual acuity determination, fundoscopy, electroretinogram, and electrooculogram. A genome-wide scan was performed, and three candidate genes mapping to the linked region were screened for mutations by direct sequencing. RESULTS: Nineteen individuals were affected by cone-rod dystrophy and four by cone dystrophy, whereas, in another subject, the diagnosis was compatible with central areolar choroidal dystrophy. The genome-wide search allowed mapping the disease locus to chromosome 6, region p12.2-p21.1, with a maximum lod score of 6.71. Analysis of key recombinants in affected individuals placed the locus to a 12-Mb region flanked by newly generated markers 6-41025 and 6-52969. Assuming complete penetrance, recombinations in two healthy individuals defined a smaller critical region of 3.7 Mb between markers 6-42153 and D6S459. Three genes mapping within the linked interval (RDS, GUCA1A, and GUCA1B) were considered excellent candidates because of their involvement in distinct forms of retinal dystrophies. However, mutation analyses of these genes failed to identify pathogenetic mutations. CONCLUSIONS: The significant lod scores obtained and the absence of mutations in RDS, GUCA1A, and GUCA1B support the existence of a novel, yet unidentified gene responsible for retinal dystrophy within the chromosome 6 cluster.

Adult↗
PubMed2005

The functional Q84R polymorphism of mammalian Tribbles homolog TRB3 is associated with insulin resistance and related cardiovascular risk in Caucasians from Italy.

Insulin resistance plays a major role in dyslipidemia, cardiovascular disease, and type 2 diabetes. TRB3, a mammalian tribbles homolog, whose chromosomal region 20p13-p12 has been linked to human type 2 diabetes, impairs insulin signaling through the inhibition of Akt phosphorylation and is overexpressed in murine models of insulin resistance. We here report that the prevalent TRB3 missense Q84R polymorphism is significantly (P < 0.05) associated with several insulin resistance-related abnormalities in two independent cohorts (n = 178 and n = 605) of nondiabetic individuals and with the presence of a cluster of insulin resistance-related cardiovascular risk factors in 716 type 2 diabetic patients (OR 3.1 [95% CI 1.2-8.2], P = 0.02). In 100 additional type 2 diabetic patients who suffered from myocardial ischemia, age at myocardial ischemia was progressively and significantly (P = 0.03) reduced from Q84Q to Q84R to R84R individuals. To test the functional role of TRB3 variants, either Q84 or R84 TRB3 full-length cDNAs were transfected in human HepG2 hepatoma cell lines. As compared with control HepG2 cells, insulin-induced Ser473-Akt phosphorylation was reduced by 22% in Q84- (P < 0.05 vs. control cells) and by 45% in R84-transfected cells (P < 0.05 vs. Q84 transfected and P < 0.01 vs. control cells). These data provide the first evidence that TRB3 gene plays a role in human insulin resistance and related clinical outcomes.

Aged↗
PubMed2004

KBG syndrome in a cohort of Italian patients.

KBG syndrome comprises a distinct facial phenotype, macrodontia, short stature, and skeletal anomalies. So far, it has been reported in 29 individuals. Recently, diagnostic criteria were outlined. Here, we describe eight new patients whose clinical and radiological findings fit the diagnostic criteria of KBG syndrome. While most patients were sporadic in occurrence, in two families the disorder was transmitted from mildly affected mothers to their affected children. The phenotype of KBG syndrome has been reviewed based on published and present patients. EEG anomalies with or without seizures, mixed hearing loss, palatal anomalies with secondary speech disorder, distinct age-related behavior, and cryptorchidism are possible additional characteristics. Less common manisfestations were posterior fossa malformations, eye defects, and congenital heart defects.

Abnormalities, Multiple↗
PubMed2004

Disomy of distal Xq in males: case report and overview.

A 46,XYq 8-year-old male was referred for microcephaly, growth, and mental retardation, hypotonia, genital hypoplasia, and dysmorphisms. FISH analysis showed that the rearranged Y chromosome originated from an unbalanced translocation of Xq27.3-qter onto the deleted Yq11.22. Analysis of reported patients with disomy of region distal to Xq26 suggests that this rare anomaly, associated with failure to dosage compensate X-linked genes that are normally inactivated, when present in two copies, is causing a quite distinct phenotype. This imbalance is the aberrant by product of the recombinogenic pairing of the distal pseudoautosomal Xq-Yq region at male meiosis.

Abnormalities, Multiple↗
PubMed2004

Variations in the NMDA receptor subunit 2B gene (GRIN2B) and schizophrenia: a case-control study.

A well established model for the pathophysiology of schizophrenia postulates a role for the NMDA-mediated glutamate transmission. The human gene coding for the 2B subunit of the NMDA receptor (GRIN2B) is considered a candidate based on its selective expression in brain. To evaluate the hypothesis that GRIN2B acts as a major gene in determining susceptibility to schizophrenia, a case-control association study was performed. Five single nucleotide polymorphisms (SNPs) were genotyped in 188 Italian patients and 156 control subjects. The association study showed a marginally significant excess of homozygosity for the polymorphism located in the 3'UTR region (P = 0.04). No other difference in genotype and allele frequencies was found in schizophrenics as compared to the control series. The case-control study was also carried out on estimated haplotypes, confirming a trend for association (P = 0.04). These results suggest that GRIN2B variations might be linked with susceptibility to schizophrenia. Replication studies on larger samples are warranted to further test this hypothesis.

3' Untranslated Regions↗
PubMed2004

The allelic variant of LAR gene promoter -127 bp T-->A is associated with reduced risk of obesity and other features related to insulin resistance.

Insulin resistance, which is pathogenic for type 2 diabetes (T2D), is under the control of largely unknown genetic determinants. LAR, a protein-tyrosine phosphatase which inhibits insulin signalling, is overexpressed in animal and human models of insulin resistance. We studied the entire sequence of the LAR gene by SSCP analysis and automatic DNA sequencing, with the aim of verifying whether its sequence variants might be associated with insulin resistance. In the 276 bp sequence upstream of the transcriptional start site (i.e. a region we have identified as having basal promoter activity) a -127 bp T-->A SNP (5% frequency) was associated with lower body mass index (BMI) ( P=0.03), waist circumference ( P=0.01), blood pressure ( P=0.01) and urinary albumin/creatinine ratio ( P=0.04) in 589 non-diabetic unrelated individuals from the Gargano region (central east coast of Italy). To quantify the risk for a high body weight conferred by the -127 T-->A SNP, the whole cohort was divided into tertiles according to the individual BMI. The risk of belonging to the heavier tertile, as compared to the leaner one, was reduced by approximately 60%. In a population from East Sicily ( n=307), T/A genotype carriers ( n=13) showed lower triglyceride levels ( P=0.04) and higher insulin sensitivity as indicated by lower plasma glucose ( P=0.03) and serum insulin ( P=0.006) during oral glucose tolerance testing (OGTT). Promoter activity, studied by cDNA transfection experiments, was similar for the A and T alleles. In conclusion, a genetic variant of the LAR gene promoter is consistently associated with features of insulin resistance in two different Caucasian populations. Although the biological relevance of this variant has yet to be determined, this finding underlines the potential importance of the LAR gene in dysregulation of insulin sensitivity and related disorders.

Adult↗
PubMed2004

Ablepharon-macrostomia syndrome in a 46-year-old woman.

Ablepharon-macrostomia syndrome (AMS) is a rare condition reported to date in 13 patients worldwide. AMS is characterized by absent or short eyelids, absent eyebrows and eyelashes, macrostomia, and external ear abnormalities. Additional features include alopecia or sparse hair, hypoplastic malar region, redundant skin, rudimentary nipples, abnormal genitalia. While the AMS phenotype is well delineated in infants and children, clinical manifestations are rather poorly characterized in adulthood. Here, we report on an Italian woman who received a diagnosis of AMS at the age of 46 years after several surgical treatments. A clinical comparison between our patient and previously reported AMS cases aids in delineating the adult phenotype of AMS and further broadens the clinical spectrum of this condition.

Ear↗
PubMed2004

Hereditary early-onset Parkinson's disease caused by mutations in PINK1.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons in the substantia nigra. We previously mapped a locus for a rare familial form of PD to chromosome 1p36 (PARK6). Here we show that mutations in PINK1 (PTEN-induced kinase 1) are associated with PARK6. We have identified two homozygous mutations affecting the PINK1 kinase domain in three consanguineous PARK6 families: a truncating nonsense mutation and a missense mutation at a highly conserved amino acid. Cell culture studies suggest that PINK1 is mitochondrially located and may exert a protective effect on the cell that is abrogated by the mutations, resulting in increased susceptibility to cellular stress. These data provide a direct molecular link between mitochondria and the pathogenesis of PD.

Amino Acid Sequence↗