Mosaic genome-wide paternal uniparental disomy after discordant results from primary fetal samples and cultured cells.

Mosaic genome-wide paternal uniparental disomy (GWpUPD) is a rare condition in which two euploid cell lines coexist in the same individual, one with biparental content and one with genome-wide paternal isodisomy. We report a complex prenatal diagnosis with discordant results from cultured and uncultured samples. A pregnant woman was referred for placental mesenchymal dysplasia and fetal omphalocele. Karyotype, array-CGH and Beckwith-Wiedemann Syndrome (BWS) testing (methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) of 11p15) performed on amniocytes were negative. After intrauterine fetal demise, the clinical suspicion persisted and BWS MS-MLPA was repeated on cultured cells from umbilical cord and amniotic fluid, revealing a mosaicism for KvH19 hypermethylation/KCNQ1OT1:TSS:DMR hypomethylation. These results, along with microsatellite analysis of the BWS region, were consistent with mosaic paternal 11p15 isodisomy. A concurrent maternal contamination exclusion test, analyzing polymorphic microsatellite markers on multiple chromosomes, showed an imbalance in favor of paternal alleles at all examined loci on cultured amniocytes and umbilical cord samples. This led to suspicion of mosaic GWpUPD, later confirmed by SNP-array, identifying a mosaic genome-wide paternal isodisomy affecting 60% of fetal cells. The assessment of mosaic GWpUPD requires multiple approaches beyond the current established diagnostic processes, also entertaining possible low-rate mosaicism. Clinical acumen and an integrated testing approach are the key to a successful diagnosis.

Copy number variation analysis implicates novel pathways in patients with oculo-auriculo-vertebral-spectrum and congenital heart defects.

Oculo-auriculo-vertebral spectrum (OAVS) is a developmental disorder of craniofacial morphogenesis. Its etiology is unclear, but assumed to be complex and heterogeneous, with contribution of both genetic and environmental factors. We assessed the occurrence of copy number variants (CNVs) in a cohort of 19 unrelated OAVS individuals with congenital heart defect. Chromosomal microarray analysis identified pathogenic CNVs in 2/19 (10.5%) individuals, and CNVs classified as variants of uncertain significance in 7/19 (36.9%) individuals. Remarkably, two subjects had small intragenic CNVs involving DACH1 and DACH2, two paralogs coding for key components of the PAX-SIX-EYA-DACH network, a transcriptional regulatory pathway controlling developmental processes relevant to OAVS and causally associated with syndromes characterized by craniofacial involvement. Moreover, a third patient showed a large duplication encompassing DMBX1/OTX3, encoding a transcriptional repressor of OTX2, another transcription factor functionally connected to the DACH-EYA-PAX network. Among the other relevant CNVs, a deletion encompassing HSD17B6, a gene connected with the retinoic acid signaling pathway, whose dysregulation has been implicated in craniofacial malformations, was also identified. Our findings suggest that CNVs affecting gene dosage likely contribute to the genetic heterogeneity of OAVS, and implicate the PAX-SIX-EYA-DACH network as novel pathway involved in the etiology of this developmental trait.

Identification of a De Novo Xq26.2 Microduplication Encompassing FIRRE Gene in a Child with Intellectual Disability.

Long non-coding RNAs (lncRNAs), defined as transcripts of >200 nucleotides not translated into protein, have been involved in a wide range of regulatory functions. Their dysregulations have been associated with diverse pathological conditions such as cancer, schizophrenia, Parkinson's, Huntington's, Alzheimer's diseases and Neurodevelopmental Disorders (NDDs), including autism spectrum disorders (ASDs). We report on the case of a five-year-old child with global developmental delay carrying a de novo microduplication on chromosome Xq26.2 region characterized by a DNA copy-number gain spanning about 147 Kb (chrX:130,813,232-130,960,617; GRCh37/hg19). This small microduplication encompassed the exons 2-12 of the functional intergenic repeating RNA element (FIRRE) gene (chrX:130,836,678-130,964,671; GRCh37/hg19) that encodes for a lncRNA involved in the maintenance of chromatin repression. The association of such a genetic alteration with a severe neurodevelopmental delay without clear dysmorphic features and congenital abnormalities indicative of syndromic condition further suggests that small Xq26.2 chromosomal region microduplications containing the FIRRE gene may be responsible for clinical phenotypes mainly characterized by structural or functioning neurological impairment.

Production and characterization of human induced pluripotent stem cells (iPSCs) from Joubert Syndrome: CSSi001-A (2850).

Joubert Syndrome (JS) is a rare autosomal recessive or X-linked condition characterized by a peculiar cerebellar malformation, known as the molar tooth sign (MTS), associated with other neurological phenotypes and multiorgan involvement. JS is a ciliopathy, a spectrum of disorders whose causative genes encode proteins involved in the primary cilium apparatus. In order to elucidate ciliopathy-associated molecular mechanisms, human induced pluripotent stem cells (hiPSCs) were derived from a patient affected by JS carrying a homozygous missense mutation in the AHI1 gene (p.H896R) that encodes a protein named Jouberin.

An emerging player in the adaptive immune response: microRNA-146a is a modulator of IL-2 expression and activation-induced cell death in T lymphocytes.

Activation of the T cell-mediated immune response has been associated with changes in the expression of specific microRNAs (miRNAs). However, the role of miRNAs in the development of an effective immune response is just beginning to be explored. This study focuses on the functional role of miR-146a in T lymphocyte-mediated immune response and provides interesting clues on the transcriptional regulation of miR-146a during T-cell activation. We show that miR-146a is low in human naive T cells and is abundantly expressed in human memory T cells; consistently, miR-146a is induced in human primary T lymphocytes upon T-cell receptor (TCR) stimulation. Moreover, we identified NF-kB and c-ETS binding sites as required for the induction of miR-146a transcription upon TCR engagement. Our results demonstrate that several signaling pathways, other than inflammation, are influenced by miR-146a. In particular, we provide experimental evidence that miR-146a modulates activation-induced cell death (AICD), acting as an antiapoptotic factor, and that Fas-associated death domain (FADD) is a target of miR-146a. Furthermore, miR-146a enforced expression impairs both activator protein 1 (AP-1) activity and interleukin-2 (IL-2) production induced by TCR engagement, thus suggesting a role of this miRNA in the modulation of adaptive immunity.

Quantitative technologies establish a novel microRNA profile of chronic lymphocytic leukemia.

MicroRNAs (miRNAs) are a novel class of small noncoding RNAs that modulate the expression of genes at the posttranscriptional level. These small molecules have been shown to be involved in cancer, apoptosis, and cell metabolism. In the present study we provide an informative profile of the expression of miRNAs in primary chronic lymphocytic leukemia (CLL) cells using 2 independent and quantitative methods: miRNA cloning and quantitative real-time-polymerase chain reaction (qRT-PCR) of mature miRNAs. Both approaches show that miR-21 and miR-155 are dramatically overexpressed in patients with CLL, although the corresponding genomic loci are not amplified. miR-150 and miR-92 are also significantly deregulated in patients with CLL. In addition, we detected a marked miR-15a and miR-16 decrease in about 11% of cases. Finally, we identified a set of miRNAs whose expression correlates with biologic parameters of prognostic relevance, particularly with the mutational status of the IgV(H) genes. In summary, the results of this study offer for the first time a comprehensive and quantitative profile of miRNA expression in CLL and their healthy counterpart, suggesting that miRNAs could play a primary role in the disease itself.