@article {10765, title = {Characterization of multi-locus imprinting disturbances and underlying genetic defects in patients with chromosome 11p15.5 related imprinting disorders.}, journal = {Epigenetics}, volume = {13}, year = {2018}, month = {2018}, pages = {897-909}, abstract = {

The identification of multilocus imprinting disturbances (MLID) appears fundamental to uncover molecular pathways underlying imprinting disorders (IDs) and to complete clinical diagnosis of patients. However, MLID genetic associated mechanisms remain largely unknown. To characterize MLID in Beckwith-Wiedemann (BWS) and Silver-Russell (SRS) syndromes, we profiled by MassARRAY the methylation of 12 imprinted differentially methylated regions (iDMRs) in 21 BWS and 7 SRS patients with chromosome 11p15.5 epimutations. MLID was identified in 50\% of BWS and 29\% of SRS patients as a maternal hypomethylation syndrome. By next-generation sequencing, we searched for putative MLID-causative mutations in genes involved in methylation establishment/maintenance and found two novel missense mutations possibly causative of MLID: one in NLRP2, affecting ADP binding and protein activity, and one in ZFP42, likely leading to loss of DNA binding specificity. Both variants were paternally inherited. In silico protein modelling allowed to define the functional effect of these mutations. We found that MLID is very frequent in BWS/SRS. In addition, since MLID-BWS patients in our cohort show a peculiar pattern of BWS-associated clinical signs, MLID test could be important for a comprehensive clinical assessment. Finally, we highlighted the possible involvement of ZFP42 variants in MLID development and confirmed NLRP2 as causative locus in BWS-MLID.

}, keywords = {Adaptor Proteins, Signal Transducing, Adolescent, Beckwith-Wiedemann Syndrome, Child, Child, Preschool, Chromosomes, Human, Pair 15, DNA Methylation, Female, Genomic Imprinting, Humans, Infant, Kruppel-Like Transcription Factors, Male, Mutation, Missense, Silver-Russell Syndrome, Young Adult}, issn = {1559-2308}, doi = {10.1080/15592294.2018.1514230}, author = {Fontana, L and Bedeschi, M F and Maitz, S and Cereda, A and Far{\'e}, C and Motta, S and Seresini, A and D{\textquoteright}Ursi, P and Orro, A and Pecile, V and Calvello, M and Selicorni, A and Lalatta, F and Milani, D and Sirchia, S M and Miozzo, M and Tabano, S} } @article {10515, title = {A complete duplication of X chromosome resulting in a tricentric isochromosome originated by centromere repositioning.}, journal = {Mol Cytogenet}, volume = {10}, year = {2017}, month = {2017}, pages = {22}, abstract = {

BACKGROUND: Neocentromeres are rare and considered chromosomal aberrations, because a non-centromeric region evolves in an active centromere by mutation. The literature reported several structural anomalies of X chromosome and they influence the female reproductive capacity or are associated to Turner syndrome in the presence of monosomy X cell line.

CASE PRESENTATION: We report a case of chromosome X complex rearrangement found in a prenatal diagnosis. The fetal karyotype showed a mosaicism with a 45,X cell line and a 46 chromosomes second line with a big marker, instead of a sex chromosome. The marker morphology and fluorescence in situ hybridization (FISH) characterization allowed us to identify a tricentric X chromosome constituted by two complete X chromosome fused at the p arms telomere and an active neocentromere in the middle, at the union of the two Xp arms, where usually are the telomeric regions. FISH also showed the presence of a paracentric inversion of both Xp arms. Furthermore, fragility figures were found in 56\% of metaphases from peripheral blood lymphocytes culture at birth: a shorter marker chromosome and an apparently acentric fragment frequently lost.

CONCLUSIONS: At our knowledge, this is the first isochromosome of an entire non-acrocentric chromosome. The neocentromere is constituted by canonical sequences but localized in an unusual position and the original centromeres are inactivated. We speculated that marker chromosome was the result of a double rearrangement: firstly, a paracentric inversion which involved the Xp arm, shifting a part of the centromere at the p end and subsequently a duplication of the entire X chromosome, which gave rise to an isochromosome. It is possible to suppose that the first event could be a result of a non-allelic homologous recombination mediated by inverted low-copy repeats. As expected, our case shows a Turner phenotype with mild facial features and no major skeletal deformity, normal psychomotor development and a spontaneous development of puberty and menarche, although with irregular menses since the last follow-up.

}, issn = {1755-8166}, doi = {10.1186/s13039-017-0323-7}, author = {Villa, N and Conconi, D and Benussi, D Gambel and Tornese, G and Crosti, F and Sala, E and Dalpr{\`a}, L and Pecile, V} } @article {8293, title = {The Klinefelter syndrome is associated with high recurrence of copy number variations on the X chromosome with a potential role in the clinical phenotype.}, journal = {Andrology}, volume = {4}, year = {2016}, month = {2016 Mar}, pages = {328-34}, abstract = {

The Klinefelter syndrome (KS) is the most frequent sex chromosomal disorder in males, characterized by at least one supernumerary X chromosome (most frequent karyotype 47,XXY). This syndrome presents with a broad range of phenotypes. The common characteristics include small testes and infertility, but KS subjects are at increased risk of hypogonadism, cognitive dysfunction, obesity, diabetes, metabolic syndrome, osteoporosis, and autoimmune disorders, which are present in variable proportion. Although part of the clinical variability might be linked to a different degree of testicular function observed in KS patients, genetic mechanisms of the supernumerary X chromosome might contribute. Gene-dosage effects and parental origin of the supernumerary X chromosome have been suggested to this regard. No study has been performed analyzing the genetic constitution of the X chromosome in terms of copy number variations (CNVs) and their possible involvement in phenotype of KS. To this aim, we performed a SNP arrays analysis on 94 KS and 85 controls. We found that KS subjects have more frequently than controls X-linked CNVs (39/94, [41.5\%] with respect to 12/42, [28.6\%] of females, and 8/43, [18.6\%] of males, p < 0.01). The number of X-linked CNVs in KS patients was 4.58 {\textpm} 1.92 CNVs/subject, significantly higher with respect to that found in control females (1.50 {\textpm} 1.29 CNVs/subject) and males (1.14 {\textpm} 0.37 CNVs/subject). Importantly, 94.4\% X-linked CNVs in KS subjects were duplications, higher with respect to control males (50.0\%, p < 0.001) and females (83.3\%, p = 0.1). Half of the X-linked CNVs fell within regions encompassing genes and most of them (90\%) included genes escaping X-inactivation in the regions of X-Y homology, particularly in the pseudoautosomal region 1 (PAR1) and Xq21.31. This study described for the first time the genetic properties of the X chromosome in KS and suggests that X-linked CNVs (especially duplications) might contribute to the clinical phenotype.

}, issn = {2047-2927}, doi = {10.1111/andr.12146}, author = {Rocca, M S and Pecile, V and Cleva, L and Speltra, E and Selice, R and Di Mambro, A and Foresta, C and Ferlin, A} } @article {1804, title = {De novo 911 Kb interstitial deletion on chromosome 1q43 in a boy with mental retardation and short stature.}, journal = {Eur J Med Genet}, volume = {55}, year = {2012}, month = {2012 Feb}, pages = {117-9}, abstract = {

Patients with distal deletions of chromosome 1q have a recognizable syndrome that includes microcephaly, hypoplasia or agenesis of the corpus callosum, and psychomotor retardation. Although these symptoms have been attributed to deletions of 1q42-1q44, the minimal chromosomal region involved has not yet defined. In this report, we describe a 7 years old male with mental retardation, cryptorchid testes, short stature and alopecia carrying only an interstitial de novo deletion of 911 Kb in the 1q43 region (239,597,095-240,508,817) encompassing three genes CHRM3, RPS7P5 and FMN2.

}, keywords = {Child, Chromosomes, Human, Pair 1, Dwarfism, Humans, Intellectual Disability, Male, Sequence Deletion}, issn = {1878-0849}, doi = {10.1016/j.ejmg.2011.11.004}, author = {Perrone, M D and Rocca, M S and Bruno, I and Faletra, F and Pecile, V and Gasparini, P} } @article {1988, title = {Phylloid pattern of hypomelanosis closely related to chromosomal abnormalities in the 13q detected by SNP array analysis.}, journal = {Dermatology}, volume = {225}, year = {2012}, month = {2012}, pages = {294-7}, abstract = {

Phylloid hypomelanosis is a distinct type of pigmentary mosaicism characterized by congenital hypochromic macules resembling a floral ornament with various elements such as round or oval patches, asymmetrical macules similar to begonia leaves, or oblong lesions. It has been found to be predominantly associated with abnormalities in chromosome 13 and sometimes as-sociated with different extracutaneous abnormalities. Here, we report 2 new cases of phylloid hypomelanosis due to mosaicism involving chromosome 13. The first one is a mosaicism for a supernumerary marker belonging to chromosome 13 and the second one is the first report of phylloid hypomelanosis associated with a mosaic deletion of 13q. Because of the extremely low level of mosaicism in these 2 cases, SNP array analysis on skin fibroblasts was carried out, showing a 13q21.33-q34 duplication (71,024,411-115,103,529) and a 13q13.3-q34 (38,368,012-115,103,529) deletion. Both cases underline on the one hand the strict connection between phylloid hypomelanosis and anomalies of chromosome 13, and on the other hand the relevance of the SNP array analysis on skin fibroblasts in the detection of low-level mosaicism.

}, keywords = {Chromosomes, Human, Pair 13, Humans, Hypopigmentation, Male, Mosaicism, Oligonucleotide Array Sequence Analysis, Polymorphism, Single Nucleotide}, issn = {1421-9832}, doi = {10.1159/000342884}, author = {Faletra, F and Berti, I and Tommasini, A and Pecile, V and Cleva, L and Alberini, E and Bruno, I and Gasparini, P} }