Publications by authors named "Antonella Fanelli"

5 Publications

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Phenotypical Characterization and Clinical Outcome of Canine Burkitt-Like Lymphoma.

Front Vet Sci 2021 17;8:647009. Epub 2021 Mar 17.

Department of Medical Veterinary Science, University of Bologna, Bologna, Italy.

In dogs, Burkitt-like lymphoma (B-LL) is rare tumor and it is classified as a high-grade B-cell malignancy. The diagnosis is challenging because of the similar histologic appearance with other histotypes, no defined phenotypical criteria and poorly described clinical aspects. The aim of the study was to provide a detailed description of clinical and morphological features, as well as immunophenotypical profile of B-LL in comparison with the human counterpart. Thirteen dogs with histologically proven B-LL, for which a complete staging and follow-up were available, were retrospectively selected. Immunohistochemical expression of CD20, PAX5, CD3, CD10, BCL2, BCL6, MYC, and caspase-3 was evaluated. Histologically, all B-LLs showed a diffuse architecture with medium to large-sized cells, high mitotic rate and diffuse starry sky appearance. B-phenotype of neoplastic cells was confirmed both by flow-cytometry and immunohistochemistry. Conversely, B-LLs were negative for BCL2 and MYC, whereas some cases co-expressed BCL6 and CD10, suggesting a germinal center B-cell origin. Disease stage was advanced in the majority of cases. All dogs received CHOP-based chemotherapy with or without immunotherapy. Despite treatment, prognosis was poor, with a median time to progression and survival of 130 and 228 days, respectively. Nevertheless, ~30% of dogs survived more than 1 year. An increased apoptotic index, a high turnover index and caspase-3 index correlated with shorter survival. In conclusion, canine B-LL shows phenotypical differences with the human counterpart along with features that might help to differentiate this entity from diffuse large B-cell lymphoma.
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March 2021

Variants in the 5'UTR reduce SHOX expression and contribute to SHOX haploinsufficiency.

Eur J Hum Genet 2021 Jan 9;29(1):110-121. Epub 2020 Jul 9.

Laboratorio di Genetica Umana, Dipartimento di Scienze della Salute, Università del Piemonte Orientale, Novara, Italy.

SHOX haploinsufficiency causes 70-90% of Léri-Weill dyschondrosteosis (LWD) and 2-10% of idiopathic short stature (ISS). Deletions removing the entire gene or enhancers and point mutations in the coding region represent a well-established cause of haploinsufficiency. During diagnostic genetic testing on ISS/LWD patients, in addition to classic SHOX defects, five 5'UTR variants (c.-58G > T, c.-55C > T, c.-51G > A, c.-19G > A, and c.-9del), were detected whose pathogenetic role was unclear and were thus classified as VUS (Variants of Uncertain Significance). The purpose of the present study was to investigate the role of these noncoding variations in SHOX haploinsufficiency. The variants were tested for their ability to interfere with correct gene expression of a regulated reporter gene (luciferase assay). The negative effect on the mRNA splicing predicted in silico for c.-19G > A was assayed in vitro through a minigene splicing assay. The luciferase assay showed that c.-51G > A, c.-19G > A, and c.-9del significantly reduce luciferase activity by 60, 35, and 40% at the homozygous state. Quantification of the luciferase mRNA showed that c.-51G > A and c.-9del might interfere with the correct SHOX expression mainly at the post-transcriptional level. The exon trapping assay demonstrated that c.-19G > A determines the creation of a new branch site causing an aberrant mRNA splicing. In conclusion, this study allowed us to reclassify two of the 5'UTR variants identified during SHOX diagnostic screening as likely pathogenic, one remains as a VUS, and two as likely benign variants. This analysis for the first time expands the spectrum of the genetic causes of SHOX haploinsufficiency to noncoding variations in the 5'UTR.
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January 2021

Co-occurrence of genomic imbalances on Xp22.1 in the SHOX region and 15q25.2 in a girl with short stature, precocious puberty, urogenital malformations and bone anomalies.

BMC Med Genomics 2019 01 9;12(1). Epub 2019 Jan 9.

Laboratory of Human Genetics, Department of Health Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy.

Background: Mutations of SHOX represent the most frequent monogenic cause of short stature and related syndromes. The genetic alterations include point mutations and deletions/duplications spanning both SHOX and its regulatory regions, although microrearrangements are confined to either the downstream or upstream enhancers in many patients. Mutations in the heterozygous state have been identified in up to 60-80% of Leri-Weill Dyschondrosteosis (LWD; MIM #127300) and approximately 4-5% of Idiopathic Short Stature (ISS; MIM#300582) patients. Homozygous or compound heterozygous mutations as well as biallelic deletions of SHOX and/or the enhancer regions result in a more severe phenotype, which is known as Langer Mesomelic Dysplasia (LMD; MIM #249700).

Case Presentation: A 17 year old girl, presented with severe short stature, growth hormone deficiency (GHD), precocious puberty, dorsal scoliosis, dysmorphisms and urogenital malformations. She was born with agenesis of the right tibia and fibula, as well as with a supernumerary digit on the left foot. Array comparative genomic hybridization (aCGH) analysis detected the presence of two distinct duplications on Xp22.1 flanking the SHOX coding sequence and involving its regulatory regions. An additional duplication of 1.6-2.5 Mb on 15q25.2 that included 13 genes was also identified. The girl was adopted and the parent's DNA was not available to establish the origin of the chromosome imbalances.

Conclusions: The complex phenotype observed in our patient is probably the result of the co-occurrence of rearrangements on chromosomes Xp22.1 and 15q25.2. The duplicated region on 15q25.2 region is likely to contain dosage-sensitive genes responsible for some of the clinical features observed in this patient, whereas the extreme short stature and the skeletal anomalies are likely attributable to the comorbidity of GHD and copy number variants in the SHOX region.
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January 2019

Novel GLI2 mutations identified in patients with Combined Pituitary Hormone Deficiency (CPHD): Evidence for a pathogenic effect by functional characterization.

Clin Endocrinol (Oxf) 2019 03 7;90(3):449-456. Epub 2019 Jan 7.

Laboratory of Genetics, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy.

Context: The Gli-family of zinc-finger transcription factors regulates the Sonic Hedgehog (Shh) signalling pathway that plays a key role in early pituitary and ventral forebrain development. Heterozygous GLI2 loss of function mutations in humans have been reported in holoprosencephaly (HPE), HPE-like phenotypes associated with pituitary anomalies and combined pituitary hormone deficiency with or without other extra-pituitary findings.

Objective: The aim of this study was the search for GLI2 mutations in a cohort of Italian CPHD patients and the assessment of a pathogenic role for the identified variants through in vitro studies.

Patients: One hundred forty-five unrelated CPHD patients diagnosed with or without extra-pituitary manifestations were recruited from different Italian centres.

Methods: The GLI2 mutation screening was carried out through direct sequencing of all the 13 exons and intron-exon boundaries. Luciferase reporter assays were performed to evaluate the role of the detected missense variants.

Results: Five different novel heterozygous non-synonymous GLI2 variants were identified in five patients. The mutations were three missense (p.Pro386Leu, p.Tyr575His, p.Ala593Val), one frameshift (p.Val1111Glyfs*19) and one nonsense (p.Arg1226X). The latter two mutants are likely pathogenic since they lead to a truncated protein. The in vitro functional study of the plasmids bearing two of the three missense variants (namely p.Tyr575His and p.Ala593Val) revealed a significant reduction in transcriptional activity.

Conclusion: In conclusion, the analysis of GLI2 in individuals with CPHD led to the identification of five variations with a likely negative impact on the GLI2 protein, confirming that GLI2 is an important causative gene in CPHD. The functional in vitro study analysis performed on the missense variations were useful to strengthen the hypothesis of pathogenicity.
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March 2019

Variations in the high-mobility group-A2 gene (HMGA2) are associated with idiopathic short stature.

Pediatr Res 2016 Feb 4;79(2):258-61. Epub 2015 Nov 4.

Department of Health Sciences, Laboratory of Human Genetics, University of Eastern Piedmont, Novara and IRCAD (Interdisciplinary Research Center of Autoimmune Diseases), Novara, Italy.

Background: Several association studies confirmed high-mobility group-A2 gene (HMGA2) polymorphisms as the most relevant variants contributing to height variability. Animal models and deletions in humans suggest that alterations of HMGA2 might be relevant in causing short stature. Together, these observations led us to investigate the involvement of HMGA2 in idiopathic short stature (ISS) through an association study and a mutation screening.

Methods: We conducted an association study (155 ISS patients and 318 normal stature controls) with three HMGA2 single-nucleotide polymorphisms (SNPs) (SNPs rs1042725, rs7968682, and rs7968902) using a TaqMan-based assay. The patients were then analyzed by direct sequencing and multiplex ligation-dependent probe amplification (MLPA) to detect point mutations and genomic micro-rearrangements.

Results: Considering a recessive model, an OR value >1 was observed for genotypes rs7968682 TT (Odds ratio (OR) = 1.72, confidence interval (CI): 1.14-2.58) and rs1042725 TT (OR = 1.51, CI: 1.00-2.28) in accordance to the effect exhibited by the single alleles in the general population. None of the patients carried possibly causative HMGA2 mutations.

Conclusion: Besides the already known role in determining variability in human height, HMGA2 polymorphisms also contribute to susceptibility to ISS. Moreover, we here report the first mutation screening performed in ISS concluding that HMGA2 has not a significant impact on the monogenic form of ISS.
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February 2016