Giulia Frisso

Polymorphism p.402Y>H in the complement factor H protein is a risk factor for age related macular degeneration in an Italian population

Aims: To evaluate the complement factor H (CFH) p.402Y>H polymorphism as a risk factor in age related macular degeneration (AMD) in an Italian population. Methods: 104 unrelated Italian AMD patients and 131 unrelated controls were screened for the CFH polymorphism p.402Y>H (c.1277 T>C), which has been associated with AMD. Retinography was obtained for patients and controls; the AMD diagnosis was confirmed by fluorescein angiograms. The c.1277 T>C polymorphism was genotyped with the TaqMan real time polymerase chain reaction single nucleotide polymorphism assay. Results: The frequency of c.1277C allele was higher in AMD patients than in controls (57.2% v 39.3%; p<0.001). The odds ratio (OR; logistic regression analysis) for AMD was 3.9 (95% confidence interval (CI): 1.9 to 8.2) for CC homozygotes. The CC genotype conferred a higher risk for sporadic (OR 4.6; CI: 2.0 to 10.5) than for familial AMD (OR 2.9; CI: 1.0 to 8.4). Genotypes were not related to either age at AMD diagnosis or to AMD phenotype. However, geographic atrophy and choroidal neovascularisation were more frequent in sporadic than in familial AMD (p = 0.027). Overall, the percentage of population attributable risk for the CC genotype was 28% (95% CI:18% to 33%). Conclusion: The association between the p.402Y>H (c.1277T>C) polymorphism and AMD applies to the Italian population and the CC genotype is more frequent in sporadic than in familial AMD cases.

Microbial diversity in Natural Whey Cultures used for the production of Caciocavallo Silano PDO cheese

The microbial diversity of sixty-three Natural Whey Cultures (NWCs) for the manufacture of Caciocavallo Silano cheese PDO was studied. The NWCs were collected from different dairies covering the whole territory of PDO production including five different regions of southern Italy. The microbial species diversity was determined by direct DNA extraction from NWCs and Polymerase Chain Reaction (PCR) amplification of variable regions of the 16S rRNA gene followed by denaturing gradient gel electrophoresis (DGGE) and denaturing high performance liquid chromatography (DHPLC). DGGE and DHPLC fingerprinting yielded the same results in terms of number of bands/peaks and specific migration/retention time of the amplicons. The DHPLC technique was used in this study for the first time to assess a food-related mixed microbial community by a culture-independent approach and proved to be at least as effective as DGGE in profiling species diversity in NWCs. Cluster analysis of DGGE and DHPLC data revealed that the species-related groups of similarity were not dependent on the geographical origin of the NWCs. The presence of three groups of 10-14 NWCs at 100% of species similarity indicated that some species associations are very commonly occurring in the NWCs for Caciocavallo Silano cheese PDO. A RAPD-PCR analysis of the NWCs was also performed for the members of the above groups and it showed that, though characterized by the same species diversity, most of the identical NWCs included different biotypes. The sequences of DGGE bands and DHPLC peaks revealed the occurrence of mainly thermophilic lactic acid bacteria such as Lactobacillus delbrueckii, L. helveticus and Streptococcus thermophilus even though the mesophilic Lactococcus lactis also occurred in some NWCs. In conclusion, the results of this study indicate that the microbial diversity of NWCs used for the Caciocavallo Silano PDO cheese is not high, it is not dependent on the geographical origin and the same microbial species occur within the territory examined. The microbiota of fermented PDO products and its possible link with territory should be studied case by case in order to have useful evidences for the assessment of product quality and authenticity.

DNA Sequence Capture and Next-Generation Sequencing for the Molecular Diagnosis of Genetic Cardiomyopathies

Hypertrophic cardiomyopathy is a relatively frequent disease with a prevalence of 0.2% worldwide and a remarkable genetic heterogeneity, with more than 30 causative genes reported to date. Current PCR-based strategies are inadequate for genomic investigations involving many candidate genes. Here, we report a next-generation sequencing procedure associated with DNA sequence capture that is able to sequence 202 cardiomyopathy-related genes simultaneously. We developed a complementary data analysis pipeline to select and prioritize genetic variants. The overall procedure can screen a large number of target genes simultaneously, thereby potentially revealing new disease-causing and modifier genes. By using this procedure, we analyzed hypertrophic cardiomyopathy patients in a shorter time and at a lower cost than with current procedures. The specificity of the next-generation sequencing-based procedure is at least as good as other techniques routinely used for mutation searching, and the sensitivity is much better. Analysis of the results showed some novel variants potentially involved in the pathogenesis of hypertrophic cardiomyopathy: a missense mutation in MYH7 and a nonsense variant in INS-IGF2 (patient 1), a splicing variant in MYBPC3 and an indel/frameshift variant in KCNQ1 (patient 2), and two concomitant variations in CACNA1C (patient 3). Sequencing of DNA from the three patients within a pool allowed detection of most variants identified in each individual patient, indicating that this approach is a feasible and cost-effective procedure.

The first case of mitochondrial acetoacetyl-CoA thiolase deficiency identified by expanded newborn metabolic screening in Italy: the importance of an integrated diagnostic approach

A pilot expanded newborn screening programme to detect inherited metabolic disorders by means of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) began in the Campania region, southern Italy, in 2007. By October 2009, >8,800 dried blood samples on filter paper from 11 hospitals had been screened. Within this screening programme, we identified a case of mitochondrial acetoacetyl-coenzyme A (CoA) thiolase deficiency [β-ketothiolase (β-KT) deficiency] by analysing the acylcarnitine profile from a dried blood spot with LC-MS/MS. Gas chromatography coupled with mass spectrometry analysis of urinary organic acids and LC-MS/MS analysis of urinary acylcarnitines were in line with this disorder. In fact, concentrations were well beyond the cut-off values of tiglyl carnitine, 3-hydroxybutyrylcarnitine and 2-methyl-3-hydroxybutyrylcarnitine, 2-methyl-3-hydroxybutyric acid and tiglyl glycine. The absence of 2-methylacetoacetic acid in urine may be attributed to: (i) the instability of this β-ketoacid because it undergoes spontaneous decarboxylation to 2-butanone, which is highly volatile and thus difficult to detect, and (ii) the good health of the patient in the first days of life. β-KT deficiency was subsequently diagnosed in the patients older sister, who showed increased levels of the same metabolites but also small amounts of 2-methylacetoacetic acid, which is considered a key marker for β-KT diagnosis. Genomic analysis revealed mutation c.1189C >G in exon 12 of the ACAT1 gene, which results in a severe defect because of the p.H397D amino acid change in both alleles of both patients.

The molecular analysis of BRCA1 and BRCA2: Next-generation sequencing supersedes conventional approaches

BACKGROUND Accurate and sensitive detection of BRCA1/2 germ-line mutations is crucial for the clinical management of women affected by breast cancer, for prevention and, notably, also for the identification of at-risk healthy relatives. The most widely used methods for BRCA1/2 molecular analysis are Sanger sequencing, and denaturing high performance liquid chromatography (dHPLC) followed by the Sanger method. However, recent findings suggest that next-generation sequencing (NGS)-based approaches may be an efficient tool for diagnostic purposes. In this context, we evaluated the effectiveness of NGS for BRCA gene analysis compared with dHPLC/Sanger sequencing. METHODS Seventy women were screened for BRCA1/2 mutations by both dHPLC/Sanger sequencing and NGS, and the data were analyzed using a bioinformatic pipeline. RESULTS Sequence data analysis showed that NGS is more sensitive in detecting BRCA1/2 variants than the conventional procedure, namely, dHPLC/Sanger. CONCLUSION Next-generation sequencing is more sensitive, faster, easier to use and less expensive than the conventional Sanger method. Consequently, it is a reliable procedure for the routine molecular screening of the BRCA1/2 genes.

Analysis of Dystrophin Gene Deletions Indicates that the Hinge III Region of the Protein Correlates with Disease Severity: Dystrophin Gene Deletions and Genotype-phenotype Correlation

We have investigated the frequency of deletions in the dystrophin gene in 108 unrelated Duchenne and Becker muscular dystrophy (DMD/BMD) patients from southern Italy (DMD, n. 47; BMD, n. 61) and identified 89 deletions. The de novo mutation rate (about 30%), and the preferentially maternal origin of deletional mutations, analysed in families in which the maternal grandparents were available or their haplotypes could be unequivocally reconstructed, are in agreement with data reported for other populations. The correlation between BMD phenotype and type of deletion suggests that, in the distal rod domain region, the deletion size may not be as crucial as the particular combination of missing exons. In fact, we provide immunohistochemical and clinical evidence that in‐frame deletion of the hinge III region in the distal rod domain results in a milder phenotype as compared with shorter deletions that do not include the hinge III region. Our data obtained in BMD patients, by confirming inferences arising from minigene transfection experiments in mdx mice, represent an important contribution to gene therapy approaches.

A child cohort study from southern Italy enlarges the genetic spectrum of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most frequent genetic cardiovascular disorder worldwide. It is the leading cause of sudden cardiac‐related death in young people and a major cause of cardiac failure and death in elderly people. However, HCM frequently goes undiagnosed until the appearance of overt signs and symptoms, thereby delaying prophylactic and therapeutic measures. We screened patients for sarcomeric genes associated with HCM to obtain information that could be useful for an early diagnosis and so limit the severe consequences of silent HCM. We recruited 39 families with HCM from southern Italy and found mutations in 41% of families (12 with familial HCM and 4 with sporadic HCM). The remaining 23 families (59%) were negative for myofilament gene mutations. Of the 12 mutations identified, 8 were novel. Screening of the other family members available revealed that 27 had mutations; 11 of these individuals had no signs or symptoms suggestive of HCM. This study, besides characterizing the spectrum of mutations in another childhood population, and revealing an even greater genetic heterogeneity than formerly recognized, may increase genotype‐phenotype correlations, and thus may help to identify asymptomatic candidates for early preventive or therapeutic measures.

NOVEL MUTATIONS AND STRUCTURAL IMPLICATIONS IN R-TYPE PYRUVATE KINASE-DEFICIENT PATIENTS FROM SOUTHERN ITALY

Deficiency of the R‐type pyruvate kinase (R‐PK) causes an autosomal recessive, hereditary, nonspherocytic hemolytic anemia (HNSHA). We screened seven unrelated patients from the south of Italy for the known mutations and found one patient homozygous for the 1529A (R510Q) mutation, two others bearing the 1456T (R486W) mutation, one homozygous and another heterozygous, and two heterozygotes for the 994A mutation (G332S). We also found three novel mutations at the heterozygote status: a G to C transversion in position 1010 (1010C; R337P) and a C to T transition in position 1492 (1492T; R498C), which are missense, and a T to G transversion in position 1523 (1523G; L508Z), which produces a stop codon with a subsequent loss of the C‐terminal protein domain. The structural features of R‐PK in the mutation‐bearing regions were examined. In all cases the mutations altered the local conformation of the enzyme. Both G332S and R337P are in highly conserved sequence regions. In particular, the R337P mutation significantly affects the intersubunit interactions, because it is located in a region subjected to a large conformational change that occurs during the R→T allosteric transition, which is essential for the enzyme activity. The R486W mutation affects an external pocketlike region, producing only a local conformational change; the R498C mutation changes the interactions among neighbouring residues; the R510Q mutation involves the loss of interdomain interactions that may reduce enzyme stability and activity. Our data also indicate that in patients from Southern Italy, pyruvate kinase deficiency is heterogeneous, the 1529A mutation, which is the most frequent mutation in the U.S. Caucasian population, having a lower frequency. Hum Mutat 11:127–134, 1998.

The multi-faceted aspects of the complex cardiac Nav1.5 protein in membrane function and pathophysiology.

The aim of this mini-review is to draw together the main concepts and findings that have emerged from recent studies of the cardiac channel protein Nav1.5. This complex protein is encoded by the SCN5A gene that, in its mutated form, is implicated in various diseases, particularly channelopathies, specifically at cardiac tissue level. Here we describe the structural, and functional aspects of Nav1.5 including post-translational modifications in normal conditions, and the main human channelopathies in which this protein may be the cause or trigger. Lastly, we also briefly discuss interacting proteins that are relevant for these channel functions in normal and disease conditions.

Prenatal diagnosis of inherited diseases: 20 years' experience of an Italian Regional Reference Centre.

Abstract Background: The demand for molecular prenatal diagnosis (PD) of inherited diseases to help high-risk couples make informed reproductive decisions has increased in the past decade. Methods: We provided multidisciplinary pre-test counselling to 1248 couples at high risk of having a child affected by an inherited disease. Results: After multidisciplinary counselling, 1171 couples requested PD for one of 73 inherited diseases. Of these, 995 (85.0%) were performed on DNA from chorionic villi (CV) and 176 (15.0%) on samples from amniocentesis. The occurrence of pregnancy loss (0.6%) and major complications did not differ significantly between the two groups. We made a diagnosis in all cases (including 8 twin pregnancies) except in 4/995 cases of CV sampling (0.4%) and in 3/176 of amniocentesis (1.7%) due to insufficient DNA. In 15 cases, molecular analysis revealed non-paternity. Conclusions: PD by analysis of foetal DNA from CV is a reliable aid in reproduction decision-making for couples at high risk of inherited diseases. The complexity of experimental procedures and the specific expertise required for the pre- and post-test multidisciplinary counselling suggest that PD be performed in reference centres also within the framework of supranational networks.