A de novo paradigm for male infertility.

De novo mutations are known to play a prominent role in sporadic disorders with reduced fitness. We hypothesize that de novo mutations play an important role in severe male infertility and explain a portion of the genetic causes of this understudied disorder. To test this hypothesis, we utilize trio-based exome sequencing in a cohort of 185 infertile males and their unaffected parents. Following a systematic analysis, 29 of 145 rare (MAF < 0.1%) protein-altering de novo mutations are classified as possibly causative of the male infertility phenotype. We observed a significant enrichment of loss-of-function de novo mutations in loss-of-function-intolerant genes (p-value = 1.00 × 10-5) in infertile men compared to controls. Additionally, we detected a significant increase in predicted pathogenic de novo missense mutations affecting missense-intolerant genes (p-value = 5.01 × 10-4) in contrast to predicted benign de novo mutations. One gene we identify, RBM5, is an essential regulator of male germ cell pre-mRNA splicing and has been previously implicated in male infertility in mice. In a follow-up study, 6 rare pathogenic missense mutations affecting this gene are observed in a cohort of 2,506 infertile patients, whilst we find no such mutations in a cohort of 5,784 fertile men (p-value = 0.03). Our results provide evidence for the role of de novo mutations in severe male infertility and point to new candidate genes affecting fertility.

Detection of oncogenic mutations in cervical carcinoma using method High Resolution Melting (HRM).

Oncogenic mutations in proto-oncogenes and tumor suppressor genes represent one of key events in cancerogenesis. In this study, we analysed mutation status in PIK3CA, KRAS and EGFR proto-oncogenes and TP53 tumor suppressor gene in a cohort of twenty-four patients diagnosed with squamous cell carcinoma or adenocarcinoma using the screening method "High Resolution Melting" (HRM). Positive findings were confirmed and identified by Sanger sequencing. Totally, we detected DNA sequence changes in targeted regions in seven patients (7/24, 29.2%). In PIK3CA gene, we found six sequence changes in four patients (4/24, 16.7%) and four of them were confirmed as oncogenic mutations. In KRAS gene, we detected sequence changes in four patients (4/24, 16.7%). Conversely, we identified pathogenic or potentially pathogenic sequence changes neither in EGFR nor TP53 genes. Our results suggest that sequence changes are specific neither for a certain histological subtype, clinical stage nor lymph node involvement and they appear independently on the presence of HPV (human papillomavirus) infection since early clinical stages. We observed the correlation between the presence of DNA sequence changes and hTERC gene amplification, but we did not find a significant relationship between the identified DNA sequence changes and detected copy-number alterations using the technique of array-CGH (array-based comparative genomic hybridization). Regardless our results confirmed an important role of oncogenic mutations in PIK3CA and KRAS genes in the neoplastic transformation process in the cervical carcinoma pathogenesis. Their identification in the early clinical stages should encourage further studies to better understand these mutations and exploit them for more detailed diagnostics.

[Identification of a Family with SUFU Germline Deletion Based on a Case of Desmoplastic Medulloblastoma in an Infant]. / Identifikace rodiny s nosicstvím germinální delece genu SUFU na podklade dia-gnózy desmoplastického meduloblastomu u batolete.

BACKGROUND: Medulloblastoma, an embryonal neuroectodermal tumor of the cerebellum, is the most common malignant brain tumor in children. There are approximately 15 cases diagnosed in the Czech Republic each year. The recent World Health Organization classification recognizes several histopathological subtypes of medulloblastoma: classical, desmoplastic/ nodular with its extensive-nodularity variant, and anaplastic/ large-cell variant. Further molecular analysis identified four basic subgroups of medulloblastoma: WNT, SHH, Group 3, and Group 4. The subgroup of SHH meduloblastoma is associated with somatic mutations of SHH, PTCH1, SUFU, SMO and TP53, while the most common mutations found in infants up to three years of age were PTCH1 and SUFU. The majority of medulloblastomas are sporadic diseases, whereas only about 5- 10% of all cases occur in connection with hereditary genetic syndromes. CASE: We present a case of a 21-months old girl diagnosed with a localized posterior fossa tumor. The histopathological examination revealed a desmoplastic/ nodular medulloblastoma. The treatment comprised a radical exstirpation of the tumor followed by adjuvant chemotherapy. With the use of array-CGH, a partial biallelic deletion of the SUFU gene (locus 10q24.32) was detected in the tumor DNA, whereas a monoallelic deletion was found in the peripheral lymphocyte DNA of the patient. These findings were confirmed by an independent qPCR method. Monoallelic germline deletion of SUFU was also identified in the patients mother, who was a healthy carrier. Pedigree of the family suggested a transition of the germline deletion of SUFU, since another brain tumors (including one case diagnosed before the age of three years) were identified in previous generations. CONCLUSION: Germline mutations in SUFU gene are believed to predispose to infant desmoplastic/ nodular medulloblastomas, basal cell carcinomas and meningiomas. The susceptibility gene shows autosomal dominant inheritance with an incomplete penetrance. There is no evidence-based surveillance strategy suggested for the carriers of germline SUFU mutations/ deletions so far. Our recommendation is based both on a family history of our patient and similar cases described in the literature. Since the germinal mutations in SUFU are responsible for up to 50% of all desmoplastic medulloblastomas in children under three years of age, genetic testing of SUFU should be encouraged in this population of patients.

Incidence of cytogenetic aberrations in two B lineage subpopulations in multiple myeloma patients analyzed by combination of whole-genome profiling and FISH.

Multiple myeloma (MM) is an incurable malignant disease of the terminal developmental stage of B-lymphocytes. While genetic heterogeneity of MM is widely described, little is known about its genetic basis as well as primary damage during plasma cells (PC) development. In this study, we focused on genome-wide screening of DNA copy number changes using oligonucleotide-based array-CGH together with I-FISH of the IgH locus rearrangements in pair samples of bone marrow B-cells (CD19+) and CD138+ PC from newly diagnosed MM patients. The IgH disruption was found in 8.9% (4/45) of CD19+ samples and in 57.8% (26/45) of CD138+ samples. The genomic profiling using array-CGH identified copy number alterations (CNAs) in 10% (2/20) of CD19+ samples in regions known to be important for MM pathogenesis. In contrast, we found CNAs in 100% (16/16) of CD138+ samples. Most common chromosomal abnormalities were trisomies of odd-numbered chromosomes (3, 5, 7, 9, 11, 15, 19 and 21), gain 1q, gain Xq and monosomy of chromosome 13. We did not find any correlation between incidence of CNAs in CD19+ and CD138+ cells. In conclusion, effective utilization of FISH and array-CGH can identify genetic lesions in premalignant stages leading to better understanding and characterization of MM.

Oligonucleotide-based array CGH as a diagnostic tool in multiple myeloma patients.

Multiple myeloma (MM) is a hematological disease caused by malignant proliferation of clonal plasma cells (PCs) known for its clinical and biological heterogeneity. Identification of chromosomal changes in genome of PCs plays a key role in MM pathogenesis and is supposed to have important prognostic significance for MM patients. There are two major genetic entities in MM. Hyperdiploid tumors (H-MM), which include about 50% of MM tumors, often have multiple trisomies involving chromosomes 3, 5, 7, 9, 11, 15, 19, and 21 and a substantially lower prevalence of IgH translocations. Nearly half of tumors are non-hyperdiploid (NH-MM), and mostly have one of five recurrent IgH translocations: 11ql13 (CCND1), 6p21 (CCND3), 16q23 (MAF), 20q12 (MAFB), and 4p16 (FGFR3 and MMSET). The development and expanded use of new technologies, such as genome-wide array-based comparative genomic hybridization (aCGH) has accelerated genomic research in MM. This technique is a powerful tool to globally analyze recurrent copy number changes in tumor genome in a single reaction and to study cancer biology and clinical behaviors. It widely overcame routinely used cytogenetic techniques (G-banding, FISH) both in minimal resolution of chromosomal changes and amount of obtained genomic data important for further analyses and clinical applications. Array CGH technique is now used to better understanding of molecular phenotypes, sensitivity to particular chemotherapeutic agents, and prognosis of these diseases. This paper brings brief literature and methodic overview of oligonucleotide-based array-CGH technique in MM diagnosis.

Transcription and replication of the influenza a virus genome.

The genome of influenza A virus consists of eight segments of negative-strand viral RNA (vRNA). During the replication cycle of the virus, the genomic vRNA is transcribed into positive-strand mRNA and complementary RNA (cRNA) in the cell nucleus. The promoter for the synthesis of mRNA molecules is located in a partially double-stranded RNA structure formed by the 5'- and 3'-terminal sequences of genomic vRNA segments. The virus encoded RNA-dependent RNA polymerase complex has to interact with both ends of the vRNA in order to generate capped RNA primers by endonucleolytic cleavage of cellular pre-mRNAs for the initiation of viral mRNA synthesis. Conserved sequence elements in the 5'-end, e.g. a polymerase binding site and a U(5-7) sequence are required for polyadenylation of virus-specific mRNAs. Polyadenylation occurs by reiterative copying of the U(5-7) sequence by the viral RNA polymerase, which is bound to the 5'end of the vRNA template. The U(5-7) sequence acts directly as a template for the poly(A)-tail. During the replication cycle of the virus, a "switch" from mRNA to cRNA synthesis occurs, but the mechanism by which this switch occurs remains unclear. The viral nucleoprotein and its interaction with the polymerase proteins and vRNA might play a role in this process. In contrast to transcription, the process of replication--the synthesis of cRNA and vRNA, which are known to occur in the absence of primers--is poorly understood.

Messenger RNAs that are not synthesized by RNA polymerase II can be 3' end cleaved and polyadenylated.

The poly(A) tail of influenza virus mRNAs is synthesized by the viral RNA polymerase by reiterative copying of a U5-7 sequence near the 5' end of the viral RNA (vRNA) template. We have engineered a vRNA molecule by replacing its viral U6 poly(A) site with a negative-sense eukaryotic polyadenylation signal. The vRNA was transcribed by the viral RNA polymerase and the transcription product was processed by the cellular 3' end processing machinery in vivo. According to the current model, 3' end processing of eukaryotic pre-mRNAs is coupled to cellular RNA polymerase II (pol II) transcription; thus only RNAs synthesized by pol III are believed to be polyadenylated efficiently. Our results show that the cellular polyadenylation machinery is nevertheless able to recognize and process RNA transcripts that are not synthesized by pol II, indicating that synthesis by pol II is not an absolute requirement for 3' end processing in vivo.