Elevated serum anti-Saccharomyces cerevisiae antibody accompanied by gut mycobiota dysbiosis as a biomarker of diagnosis in patients with de novo Parkinson disease.

BACKGROUND AND PURPOSE: Intestinal inflammation and gut microbiota dysbiosis contribute to Parkinson disease (PD) pathogenesis, and growing evidence suggests associations between inflammatory bowel diseases (IBD) and PD. Considered as markers of chronic gastrointestinal inflammation, elevated serum anti-Saccharomyces cerevisiae antibody (ASCA) levels, against certain gut fungal components, are related to IBD, but their effect on PD is yet to be investigated. METHODS: Serum ASCA IgG and IgA levels were measured using an enzyme-linked immunosorbent assay, and the gut mycobiota communities were investigated using ITS2 sequencing and analyzed using the Qiime pipeline. RESULTS: The study included 393 subjects (148 healthy controls [HCs], 140 with PD, and 105 with essential tremor [ET]). Both serum ASCA IgG and IgA levels were significantly higher in the PD group than in the ET and HC groups. Combining serum ASCA levels and the occurrence of constipation could discriminate patients with PD from controls (area under the curve [AUC] = 0.81, 95% confidence interval [CI] = 0.76-0.86) and from patients with ET (AUC = 0.85, 95% CI = 0.79-0.89). Furthermore, the composition of the gut fungal community differed between the PD and HC groups. The relative abundances of Saccharomyces cerevisiae, Aspergillus, Candida solani, Aspergillus flavus, ASV601_Fungi, ASV866_Fungi, and ASV755_Fungi were significantly higher in the PD group, and enriched Malassezia restricta was found in the HC group. CONCLUSIONS: Our study identified elevated serum ASCA levels and enriched gut Saccharomyces cerevisiae in de novo PD.

Apolipoprotein E Genotype Contributes to Motor Progression in Parkinson's Disease.

BACKGROUND: Emerging evidence indicates that the apolipoprotein E (APOE) ε4 exacerbates α-synuclein pathology. OBJECTIVE: To determine whether APOE ε4 contributes to motor progression in early Parkinson's disease (PD). METHODS: Longitudinal data were obtained from 384 patients with PD divided into APOE ε4 carriers (n = 85) and noncarriers (n = 299) in the Parkinson's Progression Marker Initiative. Participants underwent yearly motor assessments over a mean follow-up period of 78.9 months. Repeated measures and linear mixed models were used to test the effects of APOE ε4. RESULTS: The motor progression was significantly more rapid in patients with PD carrying APOE ε4 than in noncarriers (ß = 0.283, P = 0.026, 95% confidence interval: 0.033-0.532). Through subgroup analysis, we found that the effect of APOE ε4 was significant only in patients with high amyloid ß burden (ß = 0.761, P < 0.001, 95% confidence interval: 0.0356-1.167). CONCLUSIONS: APOE ε4 may be associated with rapid motor progression in PD. © 2021 International Parkinson and Movement Disorder Society.

Different patterns of exosomal α-synuclein between Parkinson's disease and probable rapid eye movement sleep behavior disorder.

BACKGROUND AND PURPOSE: The insidious onset of Parkinson's disease (PD) makes early diagnosis difficult. Notably, idiopathic rapid eye movement sleep behavior disorder (iRBD) was reported as a prodrome of PD, which may represent a breakthrough for the early diagnosis of PD. However, currently there is no reliable biomarker for PD diagnosis. Considering that α-synuclein (α-Syn) and neuroinflammation are known to develop prior to the onset of clinical symptoms in PD, it was hypothesized that plasma total exosomal α-Syn (t-exo α-Syn), neural-derived exosomal α-Syn (n-exo α-Syn) and exosomal apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC) may be potential biomarkers of PD. METHODS: In this study, 78 PD patients, 153 probable iRBD patients (pRBD) and 63 healthy controls (HCs) were recruited. α-Syn concentrations were measured using a one-step paramagnetic particle-based chemiluminescence immunoassay, and ASC levels were measured using the Ella system. RESULTS: It was found that t-exo α-Syn was significantly increased in the PD group compared to the pRBD and HC groups (p < 0.0001), whilst n-exo α-Syn levels were significantly increased in both the PD and pRBD groups compared to HCs (p < 0.0001). Furthermore, although no difference was found in ASC levels between the PD and pRBD groups, there was a positive correlation between ASC and α-Syn in exosomes. CONCLUSIONS: Our results suggest that both t-exo α-Syn and n-exo α-Syn were elevated in the PD group, whilst only n-exo α-Syn was elevated in the pRBD group. Additionally, the adaptor protein of inflammasome ASC is correlated with α-Syn and may facilitate synucleinopathy.

Associations of Body Mass Index-Metabolic Phenotypes with Cognitive Decline in Parkinson's Disease.

BACKGROUND: Growing evidence suggests important effects of body mass index (BMI) and metabolic status on neurodegenerative diseases. However, the roles of BMI and metabolic status on cognitive outcomes in Parkinson's disease (PD) may vary and are yet to be determined. METHODS: In total, 139 PD patients from the whole PD cohort in Parkinson's Progression Markers Initiative database underwent complete laboratory measurements, demographic and anthropometric parameters at baseline, and were enrolled in this study. Further, they were categorized into 4 different BMI-metabolic status phenotypes using Adult Treatment Panel-III criteria. Motor and cognition scales at baseline and longitudinal changes after a 48-month follow-up were compared among the 4 groups. Repeated-measure linear mixed models were performed to compare PD-related biomarkers among BMI-metabolic status phenotypes across time. RESULTS: We found that PD patients in the metabolically unhealthy normal weight group showed more cognitive decline in global cognition and visuospatial perception after a 48-month follow-up than those in the other 3 groups (p < 0.05). No difference was found in motor scales among different BMI-metabolic status phenotypes. Finally, compared to the metabolically healthy normal weight group, the metabolically healthy obesity group had lower CSF Aß42 and serum neurofilament levels in repeated-measure linear mixed models adjusting for age, gender, APOE e4 carrier status, and years of education (p = 0.031 and 0.046, respectively). CONCLUSION: The MUNW phenotype was associated with a rapid cognitive decline in PD.

Study of the collagen type VI alpha 3 (COL6A3) gene in Parkinson's disease.

BACKGROUND: To date, the genetic contribution to Parkinson's disease (PD) remains unclear. Mutations in the collagen type VI alpha 3 (COL6A3) gene were recently identified as a cause of isolated dystonia. Since PD and dystonia are closely related disorders with shared clinical and genetic characteristics, we explored the association between COL6A3 and PD in a Chinese cohort. METHODS: We performed genetic screening of COL6A3 in a Chinese cohort of 173 patients with sporadic PD and 200 healthy controls. We identified variants that are likely to have pathogenic effects based on: 1) a minor allele frequency of < 0.01; and 2) the variant being recognized as deleterious by at least 15 different in silico predicting tools. Finally, we tested the aggregate burden of COL6A3 on PD via SKAT-O analysis. RESULTS: First, we found compound heterozygous COL6A3 gene mutations in one early-onset PD patients. Then, we explored whether COL6A3 variants contributed to increased risk of developing PD in a Chinese population. We detected 21 rare non-synonymous variants. Pathogenicity predictions identified 7 novel non-synonymous variants as likely to be pathogenic. SKAT-O analysis further revealed that an aggregate burden of variants in COL6A3 contributes to PD (p = 0.038). CONCLUSION: An increased aggregate burden of the COL6A3 gene was detected in patients with PD.

Stress-Induced Hyperglycemia and Remote Diffusion-Weighted Imaging Lesions in Primary Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: Stress-induced hyperglycemia (SIH) is the relative transient increase in glucose during a critical illness such as intracerebral hemorrhage (ICH) and is likely to play an important role in the pathogenesis of remote diffusion-weighted imaging (DWI) lesion (R-DWIL) in primary ICH. We sought to determine the association between SIH and the occurrence of R-DWILs. METHODS: We prospectively enrolled primary ICH patients within 14 days after onset from November 2016 to May 2018. In these patients, cerebral magnetic resonance imaging was performed within 14 days after ICH onset. R-DWIL was defined as a hyperintensity signal in DWI with corresponding hypointensity in apparent diffusion coefficient, and at least 20 mm apart from the hematoma. SIH was measured by stress-induced hyperglycemia ratio (SHR). SHR was calculated by fasting blood glucose (FBG) divided by estimated average glucose derived from glycosylated hemoglobin. The included patients were dichotomized into two groups by the 50th percentile of SHR, and named as SHR (-P50) group and SHR (P50+) group, respectively. We evaluated the association between SHR and R-DWIL occurrence using multivariable logistic regression modeling adjusted for potential confounders. RESULTS: Among the 288 patients enrolled, forty-six (16.0%) of them had one or more R-DWILs. Compared with the patients in the lower 50% of SHR (SHR [-P50]), the odds ratio (OR) [95% confidence interval (CI)] for the higher 50% of SHR (SHR [P50+]) group for R-DWIL occurrence was 3.13 (1.39-7.07) in the total population and 6.33 (2.19-18.30) in population absent of background hyperglycemia after adjusting for potential covariates. Similar results were observed after further adjusted for FBG. CONCLUSIONS: Our study demonstrated that SIH was associated with the occurrence of R-DWILs in patients with primary ICH within 14 days of symptom onset.

Association of Concurrent Olfactory Dysfunction and Probable Rapid Eye Movement Sleep Behavior Disorder with Early Parkinson's Disease Progression.

Background: Parkinson's disease (PD), with either rapid eye movement sleep behavior disorder (RBD) or olfactory dysfunction (OD), has been associated with disease progression. However, there is currently heterogeneity in predicting prognosis. Objectives: To identify whether the concurrent presence of OD and probable RBD (pRBD) in PD (Dual hit in PD, PD-DH) is associated with disease progression. Methods: We included 420 patients with de novo PD from the Parkinson's Progression Markers Initiative: 180 PD only (PD), 82 PD with OD (PD-OD), 94 PD with pRBD (PD-pRBD), and 64 PD with both OD and pRBD (PD-DH). Participants underwent motor and nonmotor evaluations, dopamine transporter imaging, and cerebrospinal fluid (CSF) assessment. Data were analyzed with generalized estimating equations and Cox proportional hazards analysis. Results: The PD-DH subtype was associated with higher scores and faster progression rates in Movement Disorder Society-Unified PD Rating Scale (MDS-UPDRS) Parts II and III. Also, patients in PD-DH group had faster deterioration in nonmotor symptoms, including MDS-UPDRS Part I score, Montreal Cognitive Assessment, Hopkins Verbal Learning Test-Revised, Wechsler Memory Scale-Third edition (WMS-III) Letter Number Sequencing score, Symbol Digit Modalities Test, and Scales for Outcomes in PD-Autonomic scores, with all P values <0.002. Moreover, the PD-DH subtype had a higher mild cognitive impairment risk (hazard ratio = 1.756, 95% confidence interval [CI] = 1.132-2.722; P = 0.012), faster decline in caudate standard uptake values (ß = -0.03, 95% CI = -0.06 to -0.008, P = 0.012), and CSF α-synuclein levels (ß = -77, 95% CI = -149 to -5, P = 0.034) than the PD group. Conclusion: Coexisting pRBD and OD in patients with PD may be associated with faster progressions in motor measurements and in cognitive and autonomic symptoms, indicating PD-DH as a more aggressive subtype for PD.

From inflammasome to Parkinson's disease: Does the NLRP3 inflammasome facilitate exosome secretion and exosomal alpha-synuclein transmission in Parkinson's disease?

A pivotal neuropathological manifestation of synucleinopathies, like Parkinson's disease (PD), is the aggregation of α-synuclein. In a recent cell-to-cell transmission model of α-synuclein, α-synuclein propagation was demonstrated to resemble that of prion proteins in the central nervous system. Furthermore, exosomes, as biomolecule carriers, have been shown to transmit α-synuclein from neuron to neuron. However, the mechanisms underlying exosomal α-synuclein transmission have not been well understood. The NLR family pyrin domain containing 3 protein (NLRP3) inflammasome activation in microglia, and the subsequent release of proinflammatory cytokines, are two crucial pathological events involved in neuroinflammation and PD progression. Research has revealed that the NLRP3 inflammasome may facilitate the secretion of extracellular vesicles, as well as exosomal transmission of proteins like aggregated α-synuclein. However, only a few reports have evaluated these pathogenic mechanisms. Herein we evaluate for the first time the current evidence for the involvement of the NLRP3 inflammasome in microvesicle generation by microglial cells, and the various mechanisms regarding the production, shedding, and content of exosomes in relation to α-synuclein transmission from neuron to neuron. Furthermore, we propose a model of microglial NLRP3 inflammasome-dependent exosome secretion and exosomal α-synuclein transmission in PD. This knowledge may lead to the identification of novel potential targets for drug development and stimulate further research in PD.

Parkinson's Disease in Teneurin Transmembrane Protein 4 (TENM4) Mutation Carriers.

INTRODUCTION: Mutations in the teneurin transmembrane protein 4 (TENM4) gene, known to be involved in neuropsychiatric disorders, have been identified in three pedigree of essential tremor (ET) from Spain. ET has overlapping clinical manifestations and epidemiological symptoms with Parkinson's disease (PD), suggesting these two disorders may reflect common genetic risk factors. In this study, we investigated clinical and genetic manifestations in four unrelated pedigrees with both ET and PD in which TENM4 variants were identified. METHODS: We subsequently explored whether TENM4 variants contributed to the risk of developing PD. The frequency of TENM4 variants was evaluated from four PD pedigrees and other 407 subjects. RESULTS: The results revealed 12 different novel heterozygous variants, all at low frequency. A clear general enrichment of TENM4 variants was detected in early onset PD patients (p < 0.001, OR = 5.264, 95% CI = 1.957-14.158). CONCLUSION: The results indicate that rare TENM4 variants may be associated with an increased risk of PD.

Genetic testing of FUS, HTRA2, and TENM4 genes in Chinese patients with essential tremor.

INTRODUCTION: Essential tremor (ET) is one of the most prevalent movement disorders. The genetic etiology of ET has not been well defined although a significant proportion (≥50%) are familial cases. Linkage analysis and genome-wide association studies (GWASs) have identified several risk variants. In recent years, whole-exome sequencing of ET has revealed several specific causal variants in FUS (p.Q290X), HTRA2 (p.G399S), and TENM4 (c.4324 G>A, c.4100C>A, and c.3412G>A) genes. OBJECTIVE: To investigate the genetic contribution of these three genes to ET, the protein-coding sequences of FUS, HTRA2, and TENM4 were analyzed in a total of 238 ET patients and 272 controls from eastern China using direct Sanger sequencing. RESULTS: We identified two synonymous coding single nucleotide polymorphisms (SNPs), rs741810 and rs1052352 in FUS, and three previously reported synonymous SNPs, rs11237621, rs689369, and rs2277277 in TENM4. No nonsynonymous exonic variants were identified in these subjects. We found that the frequency of the rs1052352C allele was significantly higher (P = .001) in the ET group than in the control group. CONCLUSION: Overall, our findings suggest that rs1052352 of FUS might contribute to ET risk in Chinese population.

MRI-visible perivascular spaces are associated with cerebrospinal fluid biomarkers in Parkinson's disease.

Perivascular spaces in the brain have been known to communicate with cerebrospinal fluid and contribute to waste clearance in animal models. In this study, we sought to determine the association between MRI-visible enlarged perivascular spaces (EPVS) and disease markers in Parkinson's disease (PD). We obtained longitudinal data from 245 patients with PD and 98 healthy controls from the Parkinson's Progression Marker Initiative. Two trained neurologists performed visual ratings on T2-weighted images to characterize EPVS in the centrum semiovale (CSO), the basal ganglia (BG) and the midbrain. We found that a greater proportion of patients with PD had low grade BG-EPVS relative to healthy controls. In patients with PD, lower grade of BG-EPVS and CSO-EPVS predicted lower CSF α-synuclein and t-tau. Lower grade of BG-EPVS were also associated with accelerated Hoehn &Yahr stage progression in patients with baseline stage 1. BG-EPVS might be a valuable predictor of disease progression.

Different Perivascular Space Burdens in Idiopathic Rapid Eye Movement Sleep Behavior Disorder and Parkinson's Disease.

BACKGROUND: Excessive aggregation of α-synuclein is the key pathophysiological feature of Parkinson's disease (PD). Rapid eye movement sleep behavior disorder (RBD) is also associated with synucleinopathies and considered as a powerful predictor of PD. Growing evidence suggests the diminished clearance of α-synuclein may be partly attributable to poor interstitial fluid drainage, which can be reflected by magnetic resonance imaging (MRI)-visible enlarged perivascular space (EPVS). However, the effect of MRI-visible EPVS on iRBD and PD, and their correlation with clinical characteristics remain unclear. OBJECTIVE: To evaluate the clinical and neuroimaging significance of MRI-visible EPVS in iRBD and PD patients. METHODS: We enrolled 33 iRBD patients, 82 PD (with and without RBD) patients, and 35 healthy controls (HCs), who underwent clinical evaluation and 3.0 Tesla MRI. Two neurologists assessed MRI-visible EPVS in centrum semiovale (CSO), basal ganglia (BG), substantia nigra (SN), and brainstem (BS). Independent risk factors for iRBD and PD were investigated using multivariable logistic regression analysis. Spearman analysis was used to test the correlation of MRI-visible EPVS with clinical characteristics of patients. RESULTS: iRBD patients had significantly higher EPVS burdens (CSO, BG, SN, and BS) than PD patients. Higher CSO-EPVS and BS-EPVS burdens were independent risk factors for iRBD. Furthermore, higher CSO-EPVS and SN-EPVS burdens were positively correlated with the severity of clinical symptom in iRBD patients, and higher BG-EPVS burden was positively correlated with the severity of cognitive impairment in PD patients. CONCLUSION: iRBD and PD patients have different MRI-visible EPVS burdens, which may be related with a compensatory mechanism in glymphatic system. Lower MRI-visible EPVS burden in PD patients may be a manifestation of severe brain waste drainage dysfunction. These findings shed light on the pathophysiologic relationship between iRBD and PD with respect to neuroimaging marker of PD.

Factors Associated With Remote Diffusion-Weighted Imaging Lesions in Spontaneous Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: Remote diffusion-weighted imaging lesions (R-DWILs) have been detected in patients with spontaneous intracerebral hemorrhage (ICH) and may be correlated with clinical outcome. However, the mechanisms and characteristics of R-DWILs have not been fully elucidated. In this study, we sought to demonstrate the clinical characteristics of R-DWILs in spontaneous ICH. METHODS: We prospectively collected data with spontaneous ICH patients from November 2016 to December 2017. In these patients, cerebral magnetic resonance imaging was performed within 28 days after ICH onset. R-DWIL was defined as a hyperintensity signal in diffusion-weighted imaging with corresponding hypointensity in apparent diffusion coefficient, and at least 20 mm apart from the hematoma. We compared two groups of patients with or without R-DWIL with the demographic and clinical characteristics, laboratory parameters, and imaging characteristics, by using univariate and multivariate analysis. RESULTS: Of the 222 patients enrolled, a total of 75 R-DWILs were observed in 41 patients (18.5%). Among these lesions, the cortical and subcortical areas were the predominant locations with a proportion of 77.3%. The median diameter of R-DWILs was 7 mm (range 2-20 mm). Twelve patients were found having more than one lesion, with five among which showed R-DWILs in multiple cerebral arterial territories. In multivariate modeling, higher fasting glucose (OR 1.231; 95% CI 1.035-1.465; p = 0.019) and more severe white matter hyperintensity (WMH) (OR 6.589; 95% CI 2.975-14.592; p < 0.001) were independent factors related to the presence of R-DWILs. CONCLUSION: In our study, approximately one-fifth of ICH patients showed coexistence of R-DWIL. Higher fasting glucose and more severe WMH were associated with R-DWIL occurrence in spontaneous ICH.

[The clinical features and gene mutation analysis in a pedigree of spinocerebellar ataxia type 7].

We investigated the clinical features and gene mutation in a pedigree of spinocerebellar ataxia (SCA). A series of clinical tests was performed including visual examination, retinal angiography, visual evoked potential, electroretinogram and magnetic resonance imaging. Genomic DNA of the family members and normal controls was used for amplification of the (CAG)n repeats of SCA1, SCA2, SCA3, SCA6, SCA7, SCA17 and DRPLA genes by PCR. The number of (CAG)n was determined by 8% denaturing polyacrylamide gel electrophoresis and direct sequencing. The main features of 2 patients were ataxia, visual failure, retinal degeneration, cerebellar and pontine atrophy. A mutation in SCA7 gene was detected, while no mutations were found in SCA1, SCA2, SCA3, SCA6, SCA17 or DRPLA gene. Therefore, this is a pedigree of SCA7. Analysis of the CAG trinucleotide repeat expansion at the SCA7 locus can provide valuable insights into SCA7.

[Pathological features and gene mutation analysis in two pedigrees of diffuse palmoplantar keratoderma].

We report the clinical and pathological features of two pedigrees of palmoplantar keratoderma (PPK), the expression of keratin 9 (K9) in palm tissue and the mutation of the keratin 9 gene (KRT9). Histopathology and immunohistochemical assessment was performed to analyze the epidermis in the palm of the probands. Genomic DNA of 46 family individuals was used for amplification of exon 1 of KRT9. The mutations were determined by direct sequencing. Epidermal abnormalities in the palm of the two probands were characterized by vacuolar changes of suprabasal keratinocytes accompanied by thickening of the living epidermis and stratum corneum. K9 was also expressed in particular epithelial tissues. Direct sequencing of polymerase chain reaction products revealed heterozygous missense mutations in exon 1 of KRT9 (N160S and L167S) in the two families, respectively. N160S and L167S of KRT9 are disease-causing mutations in these two Chinese pedigrees with epidermolytic palmoplanter keratoderma (EPPK).

Clinical features and mutation spectrum in Chinese patients with CADASIL: A multicenter retrospective study.

AIM: To characterize clinical features and mutation spectrum in Chinese patients with CADASIL. METHODS: We collected 261 clinically suspected Chinese CADASIL patients from three hospitals located in different regions of China. Sanger sequencing is performed to screen the exons 2 to 24 of NOTCH3 gene. Clinical and genetic data were retrospectively studied. Haplotype analyses were performed in patients carrying p.Arg544Cys and p.Arg607Cys, respectively. RESULTS: A total of 214 patients were finally genetically diagnosed as CADASIL, with 45 known NOTCH3 mutations and a novel c.1817G>T mutation. We found that patients carrying p.Arg607Cys or p.Arg544Cys mutation located in exon 11 occupied nearly 35% in our mutation spectrum. In retrospectively study of clinical data, we found a higher number of patients having cognitive impairment and a lower number of patients having migraine with aura. Furthermore, we identified that patients carrying mutations in exon 11 seemed to experience a later disease onset (p=6.8×10-5 ). Additionally, a common haplotype was found in patients from eastern China carrying p.Arg607Cys, and the patients from Fujian carrying p.Arg544Cys shared the same haplotype with patients from Taiwan carrying p.Arg544Cys. CONCLUSIONS: These findings broaden the mutational and clinical spectrum of CADASIL and provide additional evidences for the existence of founder effect in CADASIL patients.

[IT15 gene analysis in two pedigrees of Huntington's disease].

To investigate the relationship between the clinical features and (CAG)n trinucleotide repeats in two pedigrees of Chinese Huntington's disease (HD). Clinical and neuroimaging features, the age of disease onset and pattern of transmission of the patients were studied in the two pedigrees of HD. Genomic DNA of 42 family members was used for amplification of the (CAG)n repeats of IT15 gene by PCR. The numbers of (CAG)n were determined by electrophoresis through a 6% polyacrylamide gel and direct sequence analysis. Results showed that patients in pedigree 1 were absent of the typical triad of HD symptoms or caudate atrophy. A total of 9 (5 patients and 4 asymptomatic) out of 18 family members had 40-50 (CAG)n repeats in the IT15 gene. In pedigree 2, all the patients were characterized by a triad of symptoms, including motor disturbance, cognitive impairment and psychiatric features. Three patients and two asymptomatic relatives had more than 50 (CAG)n repeats in the IT15 gene. In conclusion, the clinical symptoms are partly determined by (CAG)n repeats in the IT15 gene. The age of onset was correlated with (CAG)n repeats over 50, and the phenomenon called "anticipation" was found to have played a role.

[Hotspot of the mutations of keratin 9 gene in a diffuse palmoplantar keratoderma family].

OBJECTIVE: To identify the gene causing diffuse palmoplantar keratoderma in a Chinese pedigree. METHODS: Four normal individuals and 3 patients in a diffuse palmoplantar keratoderma family and 10 unrelated control samples were recruited. The hotspot of the mutations of keratin 9 gene was analyzed by polymerase chain reaction and direct sequencing. RESULTS: We found a G485A transition in ke ratin 9 gene, resulting in the substitution of glutamine for arginine at codon 162 in this diffuse palmoplantar keratoderma family. The mutation was not found in the 10 unrelated control samples and 4 normal individuals. CONCLUSION: The mutation G485A found in keratin 9 gene is the disease-causing mutation in the diffuse palmoplantar keratoderma family.

[Mutation analysis of keratin 9 gene in a pedigree with epidermolytic palmoplantar keratoderma].

OBJECTIVE: To identify mutations of keratin 9 (KRT9) gene in a big Chinese family with epidermolytic palmoplantar keratoderma(EPPK) combined with knuckle-pad-like lesions and nail lesions. METHODS: Genomic DNA from peripheral blood of all available members in this family and 50 unrelated healthy individuals was used for amplification of the whole coding sequence and the intron-exon boundaries of KRT9 gene by PCR; The mutation was detected by direct sequence analysis and identified by restriction endonuclease Dde I. RESULTS: A mutation of AAT>AGT at codon 160 (N160S) was found in all patients but not in unaffected family members and 50 controls. CONCLUSION: The mutation of AAT>AGT at codon 160 (N160S) is the disease-causing mutation in this Chinese pedigree with EPPK.