Retinoblastoma is a malignant tumour of the retina which most often occurs in children. Earlier studies on retinoblastoma have concentrated on the identification of key players in the disease and have not provided information on activated/inhibited signalling pathways. The dysregulation of protein phosphorylation in cancer provides clues about the affected signalling cascades in cancer. Phosphoproteomics is an ideal tool for the study of phosphorylation changes in proteins. Hence, global phosphoproteomics of retinoblastoma (RB) was carried out to identify signalling events associated with this cancer. Over 350 proteins showed differential phosphorylation in RB compared to control retina. Our study identified stress response proteins to be hyperphosphorylated in RB which included H2A histone family member X (H2AFX) and sirtuin 1. In particular, Ser140 of H2AFX also known as gamma-H2AX was found to be hyperphosphorylated in retinoblastoma, which indicated the activation of DNA damage response pathways. We also observed the activation of anti-apoptosis in retinoblastoma compared to control. These observations showed the activation of survival pathways in retinoblastoma. The identification of hyperphosphorylated protein kinases including Bromodomain containing 4 (BRD4), Lysine deficient protein kinase 1 (WNK1), and Cyclin-dependent kinase 1 (CDK1) in RB opens new avenues for the treatment of RB. These kinases can be considered as probable therapeutic targets for RB, as small-molecule inhibitors for some of these kinases are already in clinical trials for the treatment other cancers.

The clinical and genetic spectrum of hereditary sensory and autonomic neuropathy (HSAN) is still unknown in Japan. We collected a broad cohort of 33 unrelated patients with predominant sensory and/or autonomic dysfunctions, who were referred to our genetic laboratory. A gene panel sequencing targeting 18 HSAN-related genes was performed using a next-generation sequencing system. A recurrent frame shift mutation in the WNK1/HSN2 gene, c.3237_3238insT (p.Asp1080*), was detected in 5 patients. This mutation was homozygous in 4 cases and of a compound heterozygous genotype in 1 case. Geographic and haplotype analysis of all 5 patients suggested a founder event. In addition, a novel heterozygous nonsense variant, c.2615C>G (p.Ser872*), was identified. All the 5 patients presented with severe sensory and autonomic dysfunctions at birth or during adolescence. In 2 patients, an uncommon phenotype of acute pathological pain presented at ~50 years of age. Here, we present the first founder mutation of WNK1/HSN2, in addition to French Canadian, which accounts for ~15.2% of Japanese patients with HSAN in our cohort. We have also reviewed all previously described mutations in WNK1/HSN2 and reconciled their nomenclature strategy on the basis of the current longest transcript.

BACKGROUND: Common variations in the gene with no-lysine kinase 1 (WNK1) are associated with hypertension, but because of gene-environment interaction, it is difficult to fully identify the genetic contribution of WNK1 gene polymorphism to blood pressure (BP) variability. The aim of this study was to identify the effect of common WNK1 variants on the shift of BP during strict dietary interventions of salt or potassium intake.
RESULTS: A total of 342 subjects from 126 families were selected and sequentially maintained on normal diet for 3 days at baseline, a low-salt diet for 7 days (3g/day, NaCl), then a high-salt diet for 7 days (18 g/day), and high-salt diet with potassium supplementation for another 7 days (4.5 g/day, KCl). Five single nucleotide polymorphisms (SNPs) were selected from the WNK1 gene. rs880054 and rs12828016 were associated with diastolic BP (DBP) response during the low-or high-sodium intervention, and rs2301880 was significantly associated with systolic BP, DBP and mean arterial pressure responses to the high-sodium intervention (all P<0.05). Unfortunately, no associations for WNK1 SNPs and the constructed haplotype blocks of WNK1 with BP responses to high-salt-and-potassium supplement intervention reached nominal statistical significance.
CONCLUSIONS: The WNK1 gene might be mechanistically involved in the variation in BP response to dietary sodium and potassium intake among individuals, and might contribute to the variation of this complex phenotype.

WNK1 gene variants have been associated with adult blood pressure. We aimed to investigate relationships between WNK1 variants and blood pressure, as well as blood pressure change with age, in a longitudinal childhood study. Associations between single nucleotide polymorphisms in WNK1 and blood pressure and the rate of blood pressure change between 7 and 11 years were examined in the Avon Longitudinal Study of Parent and Children Study (n=5326 for systolic blood pressure at 11 years). We observed associations (P<0.05) with diastolic blood pressure gradient with age for 33 of 82 typed and imputed polymorphisms, including polymorphisms in exons 4, 10, and 11 (rs10774466, rs1012729, and rs9804992). The minor allele (G) of rs1012729 (frequency: 25.6%) was associated with a gender-adjusted change in a diastolic blood pressure gradient of -0.11 mm Hg/y (95% CI: -0.20 to -0.03 mm Hg/y; P=0.0054). No associations were shown with the systolic blood pressure gradient. At age 11 years, 30 polymorphisms showed association (P<0.05) with systolic blood pressure, including variants in exons 4 and 10 (rs10774466 and rs1012729). Only 3 polymorphisms were associated with diastolic blood pressure at 11 years. In exploration of polymorphism-dietary cation interactions on systolic blood pressure at 11 years, 59 reached significance (P<0.05; 12.3 expected by chance), mostly (n=33) related to dietary calcium. The findings show that common intronic and exonic WNK1 variants are associated with diastolic blood pressure gradient from 7 to 11 years and with systolic blood pressure at 11 years. Our study suggests that previously reported effects of WNK1 variants on blood pressure are mediated via effects on the gradient of blood pressure change with age.

Mutations in the WNK1 gene cause Gordon\'s syndrome, a rare Mendelian form of hypertension. We assessed whether common WNK1 variants might also contribute to essential hypertension (EH), a multifactorial disorder affecting > 25% of the adult population worldwide. A panel of 19 single nucleotide polymorphisms (SNPs) spanning the gene was selected from public databases and was genotyped in 100 white European families to determine the pattern of linkage disequilibrium, haplotype structure and tagging SNPs for the WNK1 locus. Eight tagging SNPs were identified with 90% power to predict common WNK1 haplotypes and SNPs. Family-based association tests were used to test for association with EH and severity of hypertension in 712 severely hypertensive families from the MRC British Genetics of Hypertension study resource. No association was found between WNK1 polymorphisms or haplotypes with hypertension; however, one SNP rs1468326, located 3 kb from the WNK1 promoter, was found to be nominally associated with severity of hypertension, with both systolic blood pressure (BP) (Z = +2.24, P = 0.025) and diastolic BP (Z = +1.99, P = 0.046). We also found nominal support for association of one common WNK1 haplotype with increased systolic BP (Z = +1.91, P = 0.053). This is the first study to perform haplotype association analysis of the WNK1 gene with EH. This finding of association between a SNP near the promoter region and the severity of hypertension suggests that increased expression of WNK1 might contribute to BP variability and susceptibility to EH similar to the mechanism of hypertension observed in Gordon\'s syndrome.