Identification of putative genetic modifying factors that influence the development of Papillon-Lefevre or Haim-Munk syndrome phenotypes
CLINICAL AND EXPERIMENTAL DERMATOLOGY
Authors: Pap, E. M.; Farkas, K.; Toth, L.; Fabos, B.; Szell, M.; Nemeth, G.; Nagy, N.
Abstract
Background Papillon-Lefevre syndrome (PLS; OMIM 245000) and Haim-Munk syndrome (HMS; OMIM 245010), which are both characterized by palmoplantar hyperkeratosis and periodontitis, are phenotypic variants of the same disease caused by mutations of the cathepsin C (CTSC) gene. Aim To identify putative genetic modifying factors responsible for the differential development of the PLS or HMS phenotypes, we investigated two Hungarian patients with different phenotypic variants (PLS and HMS) but carrying the same homozygous nonsenseCTSCmutation (c.748C/T; p.Arg250X). Methods To gain insights into phenotype-modifying associations, whole exome sequencing (WES) was performed for both patients, and the results were compared to identify potentially relevant genetic modifying factors. Results WES revealed two putative phenotype-modifying variants: (i) a missense mutation (rs34608771) of the SH2 domain containing 4A (SH2D4A) gene encoding an adaptor protein involved in intracellular signalling of cystatin F, a known inhibitor of the cathepsin protein, and (ii) a missense variant (rs55695858) of the odorant binding protein 2A (OBP2A) gene, influencing the function of the cathepsin protein through the glycosyltransferase 6 domain containing 1 (GLT6D1) protein. Conclusion Our study contributes to the accumulating evidence supporting the clinical importance of phenotype-modifying genetic factors, which have high potential to aid the elucidation of genotype-phenotype correlations and disease prognosis.
Read-through transcripts in lung: germline genetic regulation and correlation with the expression of other genes
CARCINOGENESIS
Authors: Maspero, Davide; Dassano, Alice; Pintarelli, Giulia; Noci, Sara; De Cecco, Loris; Incarbone, Matteo; Tosi, Davide; Santambrogio, Luigi; Dragani, Tommaso A.; Colombo, Francesca
Abstract
Transcripts originating from the transcriptional read through of two adjacent, similarly oriented genes have been identified in normal and neoplastic tissues, but their functional role and the mechanisms that regulate their expression are mostly unknown. Here, we investigated whether the expression of read-through transcripts previously identified in the non-involved lung tissue of lung adenocarcinoma patients was genetically regulated. Data on genome-wide single nucleotide variant genotypes and expression levels of 10 read-through transcripts in 201 samples of lung tissue were combined to identify expression quantitative trait loci (eQTLs). Then, to identify genes whose expression levels correlated with the 10 read-through transcripts, we used whole transcriptome profiles available for 154 patients. For 8 read-though transcripts, we identified 60 eQTLs (false discovery rate <0.05), including 17 cis-eQTLs and 43 trans-eQTLs. These eQTLs did not maintain their behavior on the 'parental' genes involved in the read-through transcriptional event. The expression levels of 7 readthrough transcripts were found to correlate with the expression of other genes: CHIA-PIFO and CTSC-RAB38 correlated with CHIA and RAB38, respectively, while 5 other read-through transcripts correlated with 43 unique non-parental transcripts; thus offering indications about the molecular processes in which these chimeric transcripts may be involved. We confirmed 9 eQTLs (for 4 transcripts) in the non-involved lung tissue from an independent series of 188 lung adenocarcinoma patients. Therefore, this study indicates that the expression of four read-through transcripts in normal lung tissue is under germline genetic regulation, and that this regulation is independent of that of the genes involved in the read-through event.