Progranulin peripheral levels as a screening tool for the identification of subjects with progranulin mutations in a Portuguese cohort.

BACKGROUND: Progranulin (PGRN) mutations are associated with different clinical phenotypes, including frontotemporal lobar degeneration (FTLD), corticobasal syndrome (CBS) and Alzheimer's disease (AD). As all pathogenic PGRN mutations identified so far cause disease through haploinsufficiency, determination of PGRN levels has been proposed as a reliable method to identify mutation carriers. OBJECTIVE: To evaluate the accuracy of peripheral PGRN levels in the identification of the PGRN mutation carriers detected thus far in our Portuguese cohort. METHODS: Serum PGRN levels were measured in 244 subjects (124 patients in the spectrum of FTLD, 2 asymptomatic descendants of a FTLD patient, 56 AD patients and 64 controls) by a novel commercial ELISA kit. RESULTS: Low PGRN levels were detected in 7 individuals (5 behavioral variant frontotemporal dementia, 1 CBS, and 1 still clinically unaffected) that constituted the group of the null PGRN mutation carriers previously identified in our molecular diagnostic laboratory. The pathogenic mutations found consisted of 4 insertion-deletions, causing frameshifts resulting in premature stop codons, 3 of which were novel. In addition, a normal PGRN level was found in a patient harboring a novel missense variant. For this novel ELISA kit, we established a PGRN cut-off level that identified with 100% accuracy the pathogenic mutation carriers. CONCLUSION: This study supports the use of a novel assay for the determination of PGRN levels as a screening procedure to identify patients harboring null PGRN mutations. This approach would significantly decrease the required PGRN mutation analysis workload and should be extended to other clinical phenotypes than behavioral variant frontotemporal dementia and to apparently sporadic cases.

Gene expression profiles of human glioblastomas are associated with both tumor cytogenetics and histopathology.

Despite the increasing knowledge about the genetic alterations and molecular pathways involved in gliomas, few studies have investigated the association between the gene expression profiles (GEP) and both cytogenetics and histopathology of gliomas. Here, we analyzed the GEP (U133Plus2.0 chip) of 40 gliomas (35 astrocytic tumors, 3 oligodendrogliomas, and 2 mixed tumors) and their association with tumor cytogenetics and histopathology. Unsupervised and supervised analyses showed significantly different GEP in low- vs high-grade gliomas, the most discriminating genes including genes involved in the regulation of cell proliferation, apoptosis, DNA repair, and signal transduction. In turn, among glioblastoma multiforme (GBM), 3 subgroups of tumors were identified according to their GEP, which were closely associated with the cytogenetic profile of their ancestral tumor cell clones: (i) EGFR amplification, (ii) isolated trisomy 7, and (iii) more complex karyotypes. In summary, our results show a clear association between the GEP of gliomas and tumor histopathology; additionally, among grade IV astrocytoma, GEP are significantly associated with the cytogenetic profile of the ancestral tumor cell clone. Further studies in larger series of patients are necessary to confirm our observations.

Association and expression study of PRKCH gene in a French Caucasian population with rheumatoid arthritis.

We study the association between three protein kinase C, eta gene polymorphisms (+8134C/T, rs912620, rs959728), and susceptibility to rheumatoid arthritis. One hundred French Caucasian rheumatoid arthritis trio families were genotyped. Relative quantification of protein kinase C, eta mRNA expression was performed from whole blood in 24 unrelated rheumatoid arthritis patients and in 16 healthy controls. Our results showed no significant association or linkage between the protein kinase C, eta polymorphisms, and rheumatoid arthritis. The protein kinase C, eta mRNA was expressed at lower level in rheumatoid arthritis unrelated patients than in healthy controls. This study shows that protein kinase C, eta gene is not a Rheumatoid Arthritis major susceptibility genetic factor in the French Caucasian population. Furthermore, the lower expression of this gene in rheumatoid arthritis patients comparing to healthy controls suggests that protein kinase C, eta could be associated with the patho-physiologic mechanism of rheumatoid arthritis.