Biomedical subjects

Patrice Roll

Publications and source records attributed to Patrice Roll.

8 recordsLinked to original sources

PubMed2006

SRPX2 mutations in disorders of language cortex and cognition.

The rolandic and sylvian fissures divide the human cerebral hemispheres and the adjacent areas participate in speech processing. The relationship of rolandic (sylvian) seizure disorders with speech and cognitive impairments is well known, albeit poorly understood. We have identified the Xq22 gene SRPX2 as being responsible for rolandic seizures (RSs) associated with oral and speech dyspraxia and mental retardation (MR). SRPX2 is a secreted sushi-repeat containing protein expressed in neurons of the human adult brain, including the rolandic area. The disease-causing mutation (N327S) resulted in gain-of-glycosylation of the secreted mutant protein. A second mutation (Y72S) was identified within the first sushi domain of SRPX2 in a male with RSs and bilateral perisylvian polymicrogyria and his female relatives with mild MR or unaffected carrier status. In cultured cells, both mutations were associated with altered patterns of intracellular processing, suggesting protein misfolding. In the murine brain, Srpx2 protein expression appeared in neurons at birth. The involvement of SRPX2 in these disorders suggests an important role for SRPX2 in the perisylvian region critical for language and cognitive development.

Adult↗

PubMed2006

Large-scale expression study of human mesial temporal lobe epilepsy: evidence for dysregulation of the neurotransmission and complement systems in the entorhinal cortex.

Human mesial temporal lobe epilepsies (MTLE) are the most frequent form of partial epilepsies and display frequent pharmacoresistance. The molecular alterations underlying human MTLE remain poorly understood. A two-step transcriptional analysis consisting in cDNA microarray experiments followed by quantitative RT-PCR validations was performed. Because the entorhinal cortex (EC) plays an important role in the pathophysiology of the MTLE and usually discloses no detectable or little cell loss, resected EC and each corresponding lateral temporal neocortex (LTC) of MTLE patients were used as the source of disease-associated and control RNAs, respectively. Six genes encoding (i) a serotonin receptor (HTR2A) and a neuropeptide Y receptor type 1 (NPY1R), (ii) a protein (FHL2) associating with the KCNE1 (minK) potassium channel subunit and with presenilin-2 and (iii) three immune system-related proteins (C3, HLA-DR-gamma and CD99), were found consistently downregulated or upregulated in the EC of MTLE patients as compared with non-epileptic autopsy controls. Quantitative western blot analyses confirmed decreased expression of NPY1R in all eight MTLE patients tested. Immunohistochemistry experiments revealed the existence of a perivascular infiltration of C3 positive leucocytes and/or detected membrane attack complexes on a subset of neurons, within the EC of nine out of eleven MTLE patients. To summarize, a large-scale microarray expression study on the EC of MTLE patients led to the identification of six candidate genes for human MTLE pathophysiology. Altered expression of NPY1R and C3 was also demonstrated at the protein level. Overall, our data indicate that local dysregulation of the neurotransmission and complement systems in the EC is a frequent event in human MTLE.

Adult↗

PubMed2004

Combined search for anti-beta2-glycoprotein I and anticardiolipin antibodies in antiphospholipid syndrome: contribution to diagnosis.

In this study we sought to assess (1) the diagnostic value of a combined search for anti-beta(2)-glycoprotein (abeta(2)-GPIs) and anticardiolipin antibodies (aCLs) in primary (APS I) and secondary (APS II) antiphospholipid syndrome and (2) the influence of the beta(2)-GPI preparation in the ELISA's results. abeta(2)-GPI and aCL concentrations were assessed in 70 patients with APS and compared with those in 65 patients with systemic lupus erythematosus (SLE) without clinical features of APS. In APS patients (38 with APS I, 32 with APS II), the diagnosis had to have been made at least 3 years earlier; in subjects with SLE, the diagnosis had to have been made at least 5 years earlier. All serum samples were tested for abeta(2) -GPI with the use of an in-house ELISA with an abeta(2) -GPI preparation from human plasma. Samples negative for abeta(2) -GPI were controlled with 2 additional beta(2)-GPI preparations, 1 from human serum and 1 from bovine serum. In APS, abeta(2)-GPIs were more frequent than in SLE (76% and 15%, respectively; P <.0001), mainly with IgG isotype and with significantly higher levels than those found in SLE. The specificity for APS was 92% for IgG abeta(2)-GPIs and 68% for IgG aCLs. The highest association with APS was found for the combination of the 2 markers (odds ratio 29; 95% confidence interval 10-76; P <.0001). Among the APS patients, 6 were positive for aCL only and remained negative regardless of which beta 2 -GPI preparation was used; 1 patient was aCL-negative and only positive with human beta 2 -GPI. These data emphasize the heterogeneity of the APS immunologic profile and the diagnostic possibilities of both antibodies.

Adult↗

PubMed2004

Deletions of chromosomes 1p and 19q are detectable on frozen smears of gliomas by FISH: usefulness for stereotactic biopsies.

Among diffuse gliomas, oligodendrogliomas may account for 25% of cases. They have a better prognosis and chemosensitivity as compared to astrocytomas. Genetic studies have shown a correlation between oligodendrocyte phenotype and presence of 1p/19q deletions. In addition, these deletions are of prognostic value. The aim of the present study was to describe a new method to detect 1p/19q deletions when little tumoral material is available (stereotactic biopsies (SBs)). Since smears (cytological preparations) are routinely done for intraoperative diagnosis of gliomas, we have searched for 1p/19q deletions by FISH in a series of 30 patients with a glioma. In 14 cases, loss of heterozygosity (LOH) analysis was also performed in order to validate our method. We found that FISH analysis on frozen smears was a simple, rapid and reliable method to detect 1p/19q deletions and a good concordance was found with LOH data (85%). The main advantages of FISH analysis on frozen smears are the following. First, it requires little material and can be easily done in the case of SBs. Second, it has a higher sensitivity than LOH especially in infiltrative areas of gliomas. Third, it allows detection of a codeletion 1p/19q in a single tumor cell. In contrast, LOH analysis is easier to interpret and can detect smaller and partial deletion whose pronostic significance remains to be defined. In conclusion, these two techniques can be used to investigate 1p/19q status in gliomas. The appropriate choice of one or other of these two techniques will depend on the specific questions that need to be answered.

Biopsy↗

PubMed2004

Complete loss of the cytoplasmic carboxyl terminus of the KCNQ2 potassium channel: a novel mutation in a large Czech pedigree with benign neonatal convulsions or other epileptic phenotypes.

PURPOSE: Benign neonatal familial convulsions (BNFCs) represent a rare epileptic disorder with autosomal dominant mode of inheritance. To date, two voltage-gated potassium (K+) channel genes, KCNQ2 and KCNQ3, have been identified in typical BNFC families. The study of new pedigrees may help detect new mutations and define genotype-phenotype correlations. METHODS: A large Czech family was detected in which BNFC was inherited together with a broad range of various nonneonatal epileptic phenotypes. Genetic linkage study and direct mutation analysis were performed to find the disease-causing mutation. RESULTS: In seven patients with BNFCs and no recurrence of seizures, a novel two-base-pair deletion (1369del2) was identified within the coding sequence of the KCNQ2 gene. The mutation led to a putative protein that lacked nearly all its carboxyl terminus part, which plays a critical role for the accurate expression of the functional K+ channels. Three patients with generalized tonic-clonic seizures (GTCSs), all without any history of BNFCs, also displayed 1369del2. Three other patients with other idiopathic epileptic phenotypes did not have the mutation. CONCLUSIONS: A novel 2-bp deletion within the coding sequence of the potassium channel KCNQ2 gene was detected in patients from a large and heterogeneous family with BNFCs or non-BNFC seizures.

Adolescent↗

PubMed2002

New human sodium/glucose cotransporter gene (KST1): identification, characterization, and mutation analysis in ICCA (infantile convulsions and choreoathetosis) and BFIC (benign familial infantile convulsions) families.

Cotransporters represent a major class of proteins that make use of ion gradients to drive active transport of substrate into cells. A new human gene, KST1, encoding a member of the sodium/glucose cotransporter family, was identified onto human chromosome 16p12-p11. This genomic region contains a major gene responsible for a syndrome of infantile convulsions and paroxysmal dyskinesia (ICCA syndrome), inherited as an autosomal dominant trait, as well as for benign familial infantile convulsions (BFIC). The entire coding sequence of the human KST1 gene was determined using a combination of methods including in silico comparison of its rabbit orthologous DNA complementary to RNA (cDNA) to the corresponding human genomic sequences, reverse transcription-polymerase chain reaction on human brain RNA, 5' and 3' rapid amplification of cDNA ends. The gene is divided into 16 exons and the predicted protein of 675 amino acids contains 14 transmembrane domains. It shares significant homology to the sodium-glucose transporter 1 cotransporter proteins. An alternatively spliced transcript resulting from the skipping of exon 6 led to a predicted protein lacking the 4th transmembrane domain. As ion transporters are good candidates for a large variety of human diseases, including paroxysmal disorders, a mutation search was performed in four families with ICCA or BFIC syndromes. No pathogenic mutation was found, although several polymorphic variants with amino acids exchanges were identified. Due to its broad expression in human tissues, the human KST1 gene could be involved in several other diseases mapped to human chromosome 16p12-p11.

Amino Acid Sequence↗

PubMed2002

Molecular and fluorescence in situ hybridization analysis of a 10;11 rearrangement in a case of infant acute monocytic leukemia.

Fluorescence in situ hybridization (FISH) analysis in a case of infant acute monocytic leukemia M5 revealed a complex rearrangement between chromosomes 10 and 11, leading to the disruption of the MLL gene. Using two painting probes for chromosomes 10 and 11 and a specific probe for the MLL gene localized on 11q23, we observed a paracentric inversion of the 11q13-q23 fragment translocated to 10p12. Molecular analysis showed that AF10 localized on 10p12 was the fusion partner gene of MLL in this rearrangement (10;11). This report underlined the usefulness of FISH and molecular techniques in identifying complex rearrangements.

Bone Marrow Transplantation↗

PubMed2002

Epilepsy and ionic channels.

Ion channels play critical roles in a broad range of physiological processes. In particular, they represent a common basis for the excitable properties of different tissues. Consequently, ion channels of many different types have been implicated in several human genetic disorders of the heart, brain and skeletal muscle. An increasing number of genes encoding neurotransmitter- or voltage-gated ion channel subunits have proved to be mutated in various idiopathic human epilepsies as well as in different animal models. The epilepsies could thus be considered as one of many paroxysmal disorders that are due to mutations in ion channel genes, the so-called channelopathies. However, recent data supported the hypothesis that other genes with different properties could also be responsible for human idiopathic epilepsies, thus opening new and exciting areas of research. Effort is still needed to identify the genes responsible for the large variety of other epileptic disorders inherited as Mendelian traits and evaluate the role of these genes in the more common and polygenic forms. Defining the genetic bases of the latter will also require that exhaustive association studies are performed. These studies may help understand the pathophysiology of human epilepsies and represent the first step towards the discovery of new therapeutic targets, as exemplified in the case of the KCNQ potassium channels.

Cerebral Cortex↗