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Whole-exome sequencing has been successful in identifying genetic factors contributing to familial or sporadic Parkinson's disease (PD). However, this approach has not been applied to explore the impact of de novo mutations on PD pathogenesis. Here, we sequenced the exomes of 39 early onset patients, their parents, and 20 unaffected siblings to investigate the effects of de novo mutations on PD. We identified 12 genes with de novo mutations ( MAD1L1 , NUP98 , PPP2CB , PKMYT1 , TRIM24 , CEP131 , CTTNBP2 , NUS1 , SMPD3 , MGRN1 , IFI35 , and RUSC2 ), which could be functionally relevant to PD pathogenesis. Further analyses of two independent case-control cohorts (1,852 patients and 1,565 controls in one cohort and 3,237 patients and 2,858 controls in the other) revealed that NUS1 harbors significantly more rare nonsynonymous variants ( P = 1.01E-5, odds ratio = 11.3) in PD patients than in controls. Functional studies in Drosophila demonstrated that the loss of NUS1 could reduce the climbing ability, dopamine level, and number of dopaminergic neurons in 30-day-old flies and could induce apoptosis in fly brain. Together, our data suggest that de novo mutations could contribute to early onset PD pathogenesis and identify NUS1 as a candidate gene for PD., Competing Interests: The authors declare no conflict of interest.

The major histocompatibility complex (MHC) is most closely associated with nasopharyngeal carcinoma (NPC), but the complexity of its genome structure has proven challenging for the discovery of causal MHC loci or genes. We conducted a targeted MHC sequencing in 40 Cantonese NPC patients followed by a two-stage replication in 1065 NPC cases and 2137 controls of Southern Chinese descendent. Quantitative RT-PCR analysis (qRT-PCR) was used to detect gene expression status in 108 NPC and 43 noncancerous nasopharyngeal (NP) samples. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) were used to assess the transcription factor binding site. We discovered that a novel SNP rs117565607_A at TRIM26 displayed the strongest association (OR = 1.909, Pcombined = 2.750 × 10 -19 ). We also observed that TRIM26 was significantly downregulated in NPC tissue samples with genotype AA/AT than TT. Immunohistochemistry (IHC) test also found the TRIM26 protein expression in NPC tissue samples with the genotype AA/AT was lower than TT. According to computational prediction, rs117565607 locus was a binding site for the transcription factor Yin Yang 1 (YY1). We observed that the luciferase activity of YY1 which is binding to the A allele of rs117565607 was suppressed. ChIP data showed that YY1 was binding with T not A allele. Significance analysis of microarray suggested that TRIM26 downregulation was related to low immune response in NPC. We have identified a novel gene TRIM26 and a novel SNP rs117565607_A associated with NPC risk by regulating transcriptional process and established a new functional link between TRIM26 downregulation and low immune response in NPC., (© 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Aberrant methylation of CCAAT/enhancer-binding protein alpha (CEBPA) promoter has been observed in acute myeloid leukemia. However, little is known about CEBPA promoter in myelodysplastic syndrome (MDS). The purpose of this study was to investigate the alteration of CEBPA promoter in MDS patients and further determine the association with CEBPA expression and mutation. CEBPA promoter was significantly methylated in 105 MDS patients compared to 22 controls (median 0.016 vs. 0.000) (P < 0.0001). Receiver operating characteristic curve analysis discriminated all patients or cytogenetically normal patients from normal controls. Three cases (3 %) were identified with single-mutated CEBPA and one (1 %) with double-mutated CEBPA. CEBPA methylation and mutation occurred mutually exclusive. No significant correlation was found between CEBPA expression and methylation (P = 0.586). Our findings indicate that CEBPA methylation is a common event in MDS, but could not act as a prognostic biomarker for MDS patients.

Deregulation of secreted frizzled-related protein 1 (SFRP1) has been found in many types of cancer. However, the pattern of SFRP1 expression in acute myeloid leukemia (AML) is still unclear. This study determined SFRP1 expression in patients with AML. SFRP1 expression was decreased markedly in patients with AML compared to controls (p < 0.001). White blood cell (WBC) counts increased as SFRP1 expression decreased in AML (p = 0.016). Patients with low SFRP1 expression showed a different distribution of French-American-British (FAB) subtypes M1/M2/M3 from those with high SFRP1 expression (p = 0.031). NPM1 mutation was mainly observed in patients with low SFRP1 expression (p = 0.011). There was a weak trend that patients with AML with low SFRP1 expression had shorter overall survival (OS) than those with high SFRP1 expression (p = 0.103). Our results indicate that reduced SFRP1 expression is found more frequently in the less well-differentiated subgroups of AML and is associated with NPM1 mutation in AML.

Objective: To identify the parental origin of methyl-CpG-binding protein 2 (MECP2) gene mutations in Chinese patients with Rett syndrome., Methods: Single nucleotide polymorphisms (SNPs) in intron 3 of the MECP2 gene were analyzed by PCR and sequencing in 115 patients with Rett syndrome. Then sequencing of the SNP region was performed for the fathers of the patients who had at least one SNP, to determine which allele was from the father. Then allele-specific PCR was performed and the products were sequenced to see whether the allele from father or mother harbored the mutation., Results: Seventy-six of the 115 patients had at least one SNP. Three hot SNPs were found in these patients. They were: IVS3+22C >G, IVS3+266C >T and IVS3+683C>T. Among the 76 cases, 73 had a paternal origin of MECP2 mutations, and the other 3 had a maternal origin. There were multiple types of MECP2 mutation of the paternal origin, including 4 frame shift, 2 deletion and 67 point (56C >T, 6C >G, 2A >G, 2G >T and 1A >T) mutations. The mutation types of the 3 patients with maternal origin included 2 frame shift and 1 point (C >T) mutation., Conclusion: In Chinese RTT patients, the MECP2 mutations are mostly of paternal origin.

Objective: To study the spectrum of mutations in methyl-CpG-binding protein 2 gene (MECP2) and cyclin-dependent kinase-like 5 gene (CDKL5) in Chinese pediatric patients with Rett syndrome (RTT), and establish a simple, quick, and efficient gene test method as well as screen a strategy of genetic diagnosis for RTT., Methods: Genomic DNA was extracted using standard procedures from the peripheral blood leukocytes of 117 pediatric patients diagnosed from 1987 to 2007. PCR was used to amplify the exons 1 - 4 of MECP2 using published primers. If no mutation was identified after screening exons 2 - 4, exon 1 was screened. If no mutation was identified in MECP2 by sequencing, multiplex ligation dependent probe amplification (MLPA) was employed to screen for large deletions by using P015C kit. If no mutation was identified in the MECP2 by sequencing and MLPA respectively, then the coding region of CDKL5 was screened by denaturing high performance liquid chromatography (DHPLC)., Results: The total mutation frequency in MECP2 and CDKL5 genes among all RTT patients was 82%. MECP2 mutations were found in 86% (137/159) of the patients with classical RTT and in 44% (8/18) of those with atypical RTT. Most of the mutations were missense mutations, accounting for 39%, followed in order of frequency by nonsense mutations 28%, frame shift mutations 17% and large deletions 14.5%. The eight most frequent MECP2 mutations were p.T158M (13%), p.R168X (12%), c.806delG (7%), p.R255X (6%), p.R270X (5%), p.R133C (5%), p.R306C (4%), and p.R106W (3%), with p.T158M as the most common of the MECP2 mutations and c.806delG as a hotspot mutation in Chinese patients with RTT. Only one synonymous mutation was identified in CDKL5., Conclusion: The spectrum of MECP2 mutations within the mainland Chinese RTT patients is similar to that of those patients reported in the world. p.T158M, p.R168X, c.806delG, p.R255X, p.R270X, p.R133C, p.R306C, and p.R106W are the hotspot mutations of MECP2 and c.806delG is a specific hotspot mutation in Chinese patients with RTT. The most effective method to screen mutations is to screen the exon 4. MLPA is an effective supplement to the routine methods.