Objective:To describe the clinical and pathological features of patients with myofasciitis.Methods:The clinical manifestations and auxiliary examination (laboratory, electromyogram, imaging and muscle biopsy) results of 52 patients with myofasciitis diagnosed by pathology at Peking University First Hospital from August 2002 to December 2024 were collected and analyzed.Results:Among the 52 patients (33 males and 19 females), the age of disease onset was (34.4±16.4) years (6.0-73.0 years) and the disease duration was 17.7 (0.3, 120.0) months; the main symptoms included myalgia in the distal limbs (28 cases, 53.8%), diffuse cutaneous or muscle sclerosis (21 cases, 40.4%), muscle weakness (22 cases, 42.3%) and limited joint activity (23 cases, 44.2%); 12 patients (23.1%) were combined with other diseases. All patients had no history of vaccination. Laboratory examinations showed that 80.8% (21/26) of patients had elevated C-reactive protein, 80.0% (20/25) had elevated erythrocyte sedimentation rate, and 26.5% (9/34) had elevated creatine kinase. Among 19 patients undergoing electromyography, 6 cases showed myogenic changes, 4 cases showed neurogenic changes, 1 case showed both myogenic and neurogenic changes, and 8 cases showed no obvious abnormality. Myofascial edema was observed in all 15 patients who underwent muscle magnetic resonance imaging, with partial involvement of adjacent muscles in some cases. According to myopathological changes, the 52 patients were divided into macrophagic myofasciitis in 41 cases (78.8%), lymphocytic myofasciitis in 7 cases (13.5%), and eosinophilic fasciitis in 4 cases (7.7%). Among the 52 patients, fibroblast proliferation in the myofascia was present in 39 cases (75.0%), subfascial muscle fiber atrophy in 28 cases (53.8%), and scattered muscle fiber necrosis and regeneration in 15 cases (28.8%). Major histocompatibility complex class Ⅰexpression on muscle fibers was positive in 89.5% (34/38) of patients, and membrane attack complex deposition on muscle fibers and/or capillary walls was present in 39.5% (15/38) of patients. Among 25 patients with follow-up, all received low-dose oral glucocorticoids, and 7 additionally received methotrexate, intravenous immunoglobulin, or hydroxychloroquine. During follow-up, 22 patients showed clinical improvement, 1 patient remained stable, and 2 patients died.Conclusions:Non-vaccine-associated macrophagic myofasciitis is the most common pathological subtype of myofasciitis. A few patients are concomitant with other diseases. Muscle magnetic resonance imaging is helpful in the diagnosis of the disease. Most patients respond to immunosuppressive treatment.

Objective To understand the changing composition and antibiotic resistance of bacterial species in the clinical isolates from outpatient and emergency department(hereinafter referred to as outpatients)and inpatient children over time in various hospitals,and to provide laboratory evidence for rational antibiotic use.Methods The data on clinically isolated pathogenic bacteria and antimicrobial susceptibility of isolates from outpatients and inpatient children in the CHINET program from 2015 to 2021 were collected and analyzed.Results A total of 278 471 isolates were isolated from pediatric patients in the CHINET program from 2015 to 2021.About 17.1％of the strains were isolated from outpatients,primarily group A β-hemolytic Streptococcus,Escherichia coli,and Staphylococcus aureus.Most of the strains(82.9％)were isolated from inpatients,mainly SS.aureus,E.coli,and H.influenzae.The prevalence of methicillin-resistant S.aureus(MRSA)in outpatients(24.5％)was lower than that in inpatient children(31.5％).The MRSA isolates from outpatients showed lower resistance rates to the antibiotics tested than the strains isolated from inpatient children.The prevalence of vancomycin-resistant Enterococcus faecalis or E.faecium and penicillin-resistant S.pneumoniae was low in either outpatients or inpatient children.S.pneumoniae,β-hemolytic Streptococcus and S.viridans showed high resistance rates to erythromycin.The prevalence of erythromycin-resistant group A β-hemolytic Streptococcus was higher in outpatients than that in inpatient children.The prevalence of β-lactamase-producing H.influenzae showed an overall upward trend in children,but lower in outpatients(45.1％)than in inpatient children(59.4％).The prevalence of carbapenem-resistant Klebsiella pneumoniae(CRKpn),carbapenem-resistant Pseudomonas aeruginosa(CRPae)and carbapenem-resistant Acinetobacter baumannii(CRAba)was 14％,11.7％,47.8％in outpatients,but 24.2％,20.6％,and 52.8％in inpatient children,respectively.The prevalence of multidrug-resistant E.coli,K.pneumoniae,Proteus mirabilis,P.aeruginosa and A.baumannii strains was lower in outpatients than in inpatient children.The prevalence of fluoroquinolone-resistant E.coli,ESBLs-producing K.pneumoniae,ESBLs-producing P.mirabilis,carbapenem-resistant E.coli(CREco),CRKpn,and CRPae was lower in children in outpatients than in inpatient children,but the prevalence of CRAba in 2021 was higher than in inpatient children.Conclusions The distribution of clinical isolates from children is different between outpatients and inpatients.The prevalence of MRSA,ESBL,and CRO was higher in inpatient children than in outpatients.Antibiotics should be used rationally in clinical practice based on etiological diagnosis and antimicrobial susceptibility test results.Ongoing antimicrobial resistance surveillance and prevention and control of hospital infections are crucial to curbing bacterial resistance.

Objective To investigate the changing antibiotic resistance profiles of E.coli isolated from patients in the 52 hospitals participating in the CHINET program from 2015 to 2021.Methods Antimicrobial susceptibility was tested for clinical isolates of E.coli according to the unified protocol of CHINET program.WHONET 5.6 and SPSS 20.0 software were used for data analysis.Results Atotal of 289 760 nonduplicate clinical strains ofE.coli were isolated from 2015 to 2021,mainly from urine samples(44.7±3.2)％.The proportion of E.coli strains isolated from urine samples was higher in females than in males(59.0％vs 29.5％).The proportion of E.coli strains isolated from respiratory tract and cerebrospinal fluid samples was significantly higher in children than in adults(16.7％vs 7.8％,0.8％vs 0.1％,both P＜0.05).The isolates from internal medicine department accounted for the largest proportion(28.9±2.8)％with an increasing trend over years.Overall,the prevalence of ESBLs-producing E.coli and carbapenem resistant E.coli(CREco)was 55.9％and 1.8％,respectively during the 7-year period.The prevalence of ESBLs-producing E.coli was the highest in tertiary hospitals each year from 2015 to 2021 compared to secondary hospitals.The prevalence of CREco was higher in children's hospitals compared to secondary and tertiary hospitals each year from 2015 to 2021.The prevalence of ESBLs-producing E.coli in tertiary hospitals and children's hospitals and the prevalence of CREco in children's hospitals showed a decreasing trend over the 7-year period.The prevalence of CREco in secondary and tertiary hospitals increased slowly.Antibiotic resistance rates changed slowly from 2015 to 2021.Carbapenem drugs(imipenem,meropenem)were the most active drugs amongβ-lactams against E.coli(resistance rate≤2.1％).The resistance rates of E.coli to β-lactam/β-lactam inhibitor combinations(piperacillin-tazobactam,cefoperazone-sulbactam),aminoglycosides(amikacin),nitrofurantoin and fosfomycin(for urinary isolates only)were all less than 10％.The resistance rate of E.coli strains to antibiotics varied with the level of hospitals and the departments where the strains were isolated,especially for cefazolin and ciprofloxacin,to which the resistance rate of E.coli strains from children in non-ICU departments was significantly lower than that of the strains isolated from other departments(P＜0.05).The E.coli isolates from ICU showed higher resistance rate to most antimicrobial agents tested(excluding tigecycline)than the strains isolated from other departments.The E.coli strains isolated from tertiary hospitals showed higher resistance rates to the antimicrobial agents tested(excluding tigecycline,polymyxin B,cefepime and carbapenems)than the strains from secondary hospitals and children's hospitals.Conclusions E.coli is an important pathogen causing clinical infection.More than half of the clinical isolates produced ESBL.The prevalence of CREco is increasing in secondary and tertiary hospitals over the 7-year period even though the overall prevalence is still low.This is an issue of concern.

Objective:To summarize the clinical and genetic characteristics of late-onset facioscapulohumeral muscular dystrophy type 1 (FSHD1) patients, and to compare the differences between late-onset and classic-onset FSHD1 patients.Methods:A retrospective analysis was conducted on the clinical and genetic data of genetically confirmed late-onset FSHD1 patients (age at onset30 years) between January 2007 and June 2024 from the Department of Neurology of Peking University First Hospital and the First Affiliated Hospital of Fujian Medical University. Classic-onset FSHD1 patients (10 yearsage at onset≤30 years) were matched 1∶1 according to sex and disease duration for comparison. The demographic information, the number of D4Z4 repeat units, the distal D4Z4 methylation levels, FSHD Clinical Score (CS), Clinical Severity Score (CSS), and Age-Corrected Clinical Severity Score (ACSS) of these patients were collected. Survival analysis was performed to compare the outcome of lower extremity involvement between late-onset and classic-onset FSHD1 patients. The correlation of the number of D4Z4 repeat units and D4Z4 methylation level with CS and ACSS was analyzed in late-onset FSHD1 patients.Results:A total of 61 patients with late-onset FSHD1 were enrolled, 33 (54.1%) of whom are female, with an age of 54.0 (46.0, 62.0) years and a disease duration of 14.0 (5.5, 22.5) years. Compared to classic-onset FSHD1 patients, late-onset patients exhibited significantly lower CS [7.0 (5.6, 8.4) vs 6.0 (4.4, 7.7), U=1 416.000, P=0.013], CSS [3.0 (2.8, 3.3) vs 3.0 (2.0, 4.0), U=2 352.000, P=0.010], and ACSS [189.2 (137.1, 241.3) vs 96.8 (61.3, 132.2), U=3 225.500, P0.001], and higher proportion of patients with limb girdle involvement but no facial muscle involvement [18.0% (11/61) vs 6.6% (4/61), χ2=3.725, P=0.054]. Kaplan-Meier survival analysis showed that the onset age of lower extremity involvement in late-onset patients (45 years, 95% CI 42-48 years) was significantly higher than that in classic-onset patients (24 years, 95% CI 21-27 years, χ2=61.012, P0.001). The duration from symptom onset to lower extremity involvement in late-onset patients (15 years, 95% CI 10-20 years) was significantly longer than that in classic-onset patients (8 years, 95% CI 3-13 years, χ2=9.105, P=0.003). Late-onset FSHD1 patients carried higher average distal D4Z4 methylation levels compared to those with classic-onset FSHD1 [46.68% (40.79%,52.57%) vs 41.02% (34.03%,48.00%), U=1 378.500, P=0.014]. Among late-onset FSHD1 patients, cytosine-phosphate-guanine 6 (CpG6) methylation levels were significantly negatively correlated with ACSS ( r=-0.278, P=0.025); the number of D4Z4 repeat units were significantly negatively correlated with ACSS ( r=-0.272, P=0.034);CpG6 methylation levels were significantly negatively correlated with CS ( r=-0.441, P=0.003), while no correlation was found between number of D4Z4 repeat units and CS ( r=-0.161, P=0.310). Conclusions:Compared with classic-onset FSHD1 patients, late-onset FSHD1 patients are associated with a higher degree of distal D4Z4 methylation, along with a milder muscle weakness phenotype, slower disease progression and a higher proportion of cases without facial muscle involvement. The age at onset can be used as a marker of the severity and prognosis in FSHD1.

Objective To understand the changing composition and antibiotic resistance of bacterial species in the clinical isolates from outpatient and emergency department(hereinafter referred to as outpatients)and inpatient children over time in various hospitals,and to provide laboratory evidence for rational antibiotic use.Methods The data on clinically isolated pathogenic bacteria and antimicrobial susceptibility of isolates from outpatients and inpatient children in the CHINET program from 2015 to 2021 were collected and analyzed.Results A total of 278 471 isolates were isolated from pediatric patients in the CHINET program from 2015 to 2021.About 17.1％of the strains were isolated from outpatients,primarily group A β-hemolytic Streptococcus,Escherichia coli,and Staphylococcus aureus.Most of the strains(82.9％)were isolated from inpatients,mainly SS.aureus,E.coli,and H.influenzae.The prevalence of methicillin-resistant S.aureus(MRSA)in outpatients(24.5％)was lower than that in inpatient children(31.5％).The MRSA isolates from outpatients showed lower resistance rates to the antibiotics tested than the strains isolated from inpatient children.The prevalence of vancomycin-resistant Enterococcus faecalis or E.faecium and penicillin-resistant S.pneumoniae was low in either outpatients or inpatient children.S.pneumoniae,β-hemolytic Streptococcus and S.viridans showed high resistance rates to erythromycin.The prevalence of erythromycin-resistant group A β-hemolytic Streptococcus was higher in outpatients than that in inpatient children.The prevalence of β-lactamase-producing H.influenzae showed an overall upward trend in children,but lower in outpatients(45.1％)than in inpatient children(59.4％).The prevalence of carbapenem-resistant Klebsiella pneumoniae(CRKpn),carbapenem-resistant Pseudomonas aeruginosa(CRPae)and carbapenem-resistant Acinetobacter baumannii(CRAba)was 14％,11.7％,47.8％in outpatients,but 24.2％,20.6％,and 52.8％in inpatient children,respectively.The prevalence of multidrug-resistant E.coli,K.pneumoniae,Proteus mirabilis,P.aeruginosa and A.baumannii strains was lower in outpatients than in inpatient children.The prevalence of fluoroquinolone-resistant E.coli,ESBLs-producing K.pneumoniae,ESBLs-producing P.mirabilis,carbapenem-resistant E.coli(CREco),CRKpn,and CRPae was lower in children in outpatients than in inpatient children,but the prevalence of CRAba in 2021 was higher than in inpatient children.Conclusions The distribution of clinical isolates from children is different between outpatients and inpatients.The prevalence of MRSA,ESBL,and CRO was higher in inpatient children than in outpatients.Antibiotics should be used rationally in clinical practice based on etiological diagnosis and antimicrobial susceptibility test results.Ongoing antimicrobial resistance surveillance and prevention and control of hospital infections are crucial to curbing bacterial resistance.

Objective To investigate the changing antibiotic resistance profiles of E.coli isolated from patients in the 52 hospitals participating in the CHINET program from 2015 to 2021.Methods Antimicrobial susceptibility was tested for clinical isolates of E.coli according to the unified protocol of CHINET program.WHONET 5.6 and SPSS 20.0 software were used for data analysis.Results Atotal of 289 760 nonduplicate clinical strains ofE.coli were isolated from 2015 to 2021,mainly from urine samples(44.7±3.2)％.The proportion of E.coli strains isolated from urine samples was higher in females than in males(59.0％vs 29.5％).The proportion of E.coli strains isolated from respiratory tract and cerebrospinal fluid samples was significantly higher in children than in adults(16.7％vs 7.8％,0.8％vs 0.1％,both P＜0.05).The isolates from internal medicine department accounted for the largest proportion(28.9±2.8)％with an increasing trend over years.Overall,the prevalence of ESBLs-producing E.coli and carbapenem resistant E.coli(CREco)was 55.9％and 1.8％,respectively during the 7-year period.The prevalence of ESBLs-producing E.coli was the highest in tertiary hospitals each year from 2015 to 2021 compared to secondary hospitals.The prevalence of CREco was higher in children's hospitals compared to secondary and tertiary hospitals each year from 2015 to 2021.The prevalence of ESBLs-producing E.coli in tertiary hospitals and children's hospitals and the prevalence of CREco in children's hospitals showed a decreasing trend over the 7-year period.The prevalence of CREco in secondary and tertiary hospitals increased slowly.Antibiotic resistance rates changed slowly from 2015 to 2021.Carbapenem drugs(imipenem,meropenem)were the most active drugs amongβ-lactams against E.coli(resistance rate≤2.1％).The resistance rates of E.coli to β-lactam/β-lactam inhibitor combinations(piperacillin-tazobactam,cefoperazone-sulbactam),aminoglycosides(amikacin),nitrofurantoin and fosfomycin(for urinary isolates only)were all less than 10％.The resistance rate of E.coli strains to antibiotics varied with the level of hospitals and the departments where the strains were isolated,especially for cefazolin and ciprofloxacin,to which the resistance rate of E.coli strains from children in non-ICU departments was significantly lower than that of the strains isolated from other departments(P＜0.05).The E.coli isolates from ICU showed higher resistance rate to most antimicrobial agents tested(excluding tigecycline)than the strains isolated from other departments.The E.coli strains isolated from tertiary hospitals showed higher resistance rates to the antimicrobial agents tested(excluding tigecycline,polymyxin B,cefepime and carbapenems)than the strains from secondary hospitals and children's hospitals.Conclusions E.coli is an important pathogen causing clinical infection.More than half of the clinical isolates produced ESBL.The prevalence of CREco is increasing in secondary and tertiary hospitals over the 7-year period even though the overall prevalence is still low.This is an issue of concern.

Objective:This study aims to explore whether there are specific behavioral deficits of response inhibition and emotional processing in patients with checking obsessive-compulsive disorder (OCD) and those with washing OCD.Methods:A cross-sectional study was conducted from January 2020 to December 2022, collecting clinical data from 75 OCD patients at the outpatient psychological consultation clinic of Xiangya Second Hospital and the clinical psychology department of Hunan Brain Hospital. The sample included 40 OCD patients with checking type (checking group, 24 males, 16 females, aged 14-34 years, mean age 22.1±5.0 years) and 35 OCD patients with washing type (washing group, 12 males, 23 females, aged 14-41 years, mean age 22.6±6.7 years). An age-matched healthy control group (control group) of 80 individuals (HCs, 37 males and 43 females, aged 14-25 years, mean age 20.8±1.9 years) was also recruited. All participants completed the Go/No-go task and Hariri task with behavioral data recorded. The Dimensional Yale-Brown Obsessive-Compulsive Scale was used to assess the severity of OCD symptoms. The Center for Epidemiologic Studies Depression Scale (CES-D) and State Anxiety Inventory (STAI) were used to assess the severity of depression and anxiety. A 3 (group: checking OCD, washing OCD and HC)×2 (task type: Go vs. No-go/Shape vs. Face) repeated-measures ANOVA was conducted to compare the behavioral performance across tasks.Results:Compared with HC group, both checking OCD group and washing OCD group had significantly higher scores in depression and anxiety ( F=85.43, 32.33,both P<0.05). When performing Go/No-go task, a significant group×task interaction effect was observed ( F3(2, 152)=3.23, P3=0.042, partialη32=0.04). In the checking OCD group, No-go accuracy was significantly lower than Go accuracy (accuracy=0.821 vs. 0.893, P<0.001); the checking OCD had significantly lower accuracy than HC in the No-go task (accuracy=0.821 vs. 0.876, P=0.005); there were no significant group differences between the washing OCD and HC in the No-go task ( P>0.05). When performing Hariri task, a significant group×task interaction effect was found ( F3(2, 152)=4.91, P3=0.009, partial η32=0.06). The washing OCD group showed significantly lower accuracy in matching emotional faces than the control group (0.879 vs. 0.936, P=0.001), whereas the checking OCD group showed no significant difference from the HC ( P>0.05); there were no significant group differences in shape matching task ( P>0.05). The accuracy of shape matching task was significantly higher than face matching task in the three groups (shape: checking OCD=0.936,washing OCD=0.929,HC=0.943; face:checking OCD=0.877,washing OCD=0.844,HC=0.917;all P>0.05). Conclusions:Checking OCD and washing OCD exhibit distinct behavioral impairment patterns in response inhibition and emotional processing. Checking-type OCD is primarily characterized by impaired response inhibition, whereas washing-type OCD is mainly associated with deficits in emotion processing.

Objective:To describe the clinical and pathological features of patients with myofasciitis.Methods:The clinical manifestations and auxiliary examination (laboratory, electromyogram, imaging and muscle biopsy) results of 52 patients with myofasciitis diagnosed by pathology at Peking University First Hospital from August 2002 to December 2024 were collected and analyzed.Results:Among the 52 patients (33 males and 19 females), the age of disease onset was (34.4±16.4) years (6.0-73.0 years) and the disease duration was 17.7 (0.3, 120.0) months; the main symptoms included myalgia in the distal limbs (28 cases, 53.8%), diffuse cutaneous or muscle sclerosis (21 cases, 40.4%), muscle weakness (22 cases, 42.3%) and limited joint activity (23 cases, 44.2%); 12 patients (23.1%) were combined with other diseases. All patients had no history of vaccination. Laboratory examinations showed that 80.8% (21/26) of patients had elevated C-reactive protein, 80.0% (20/25) had elevated erythrocyte sedimentation rate, and 26.5% (9/34) had elevated creatine kinase. Among 19 patients undergoing electromyography, 6 cases showed myogenic changes, 4 cases showed neurogenic changes, 1 case showed both myogenic and neurogenic changes, and 8 cases showed no obvious abnormality. Myofascial edema was observed in all 15 patients who underwent muscle magnetic resonance imaging, with partial involvement of adjacent muscles in some cases. According to myopathological changes, the 52 patients were divided into macrophagic myofasciitis in 41 cases (78.8%), lymphocytic myofasciitis in 7 cases (13.5%), and eosinophilic fasciitis in 4 cases (7.7%). Among the 52 patients, fibroblast proliferation in the myofascia was present in 39 cases (75.0%), subfascial muscle fiber atrophy in 28 cases (53.8%), and scattered muscle fiber necrosis and regeneration in 15 cases (28.8%). Major histocompatibility complex class Ⅰexpression on muscle fibers was positive in 89.5% (34/38) of patients, and membrane attack complex deposition on muscle fibers and/or capillary walls was present in 39.5% (15/38) of patients. Among 25 patients with follow-up, all received low-dose oral glucocorticoids, and 7 additionally received methotrexate, intravenous immunoglobulin, or hydroxychloroquine. During follow-up, 22 patients showed clinical improvement, 1 patient remained stable, and 2 patients died.Conclusions:Non-vaccine-associated macrophagic myofasciitis is the most common pathological subtype of myofasciitis. A few patients are concomitant with other diseases. Muscle magnetic resonance imaging is helpful in the diagnosis of the disease. Most patients respond to immunosuppressive treatment.

Objective:To summarize the clinical and genetic characteristics of late-onset facioscapulohumeral muscular dystrophy type 1 (FSHD1) patients, and to compare the differences between late-onset and classic-onset FSHD1 patients.Methods:A retrospective analysis was conducted on the clinical and genetic data of genetically confirmed late-onset FSHD1 patients (age at onset30 years) between January 2007 and June 2024 from the Department of Neurology of Peking University First Hospital and the First Affiliated Hospital of Fujian Medical University. Classic-onset FSHD1 patients (10 yearsage at onset≤30 years) were matched 1∶1 according to sex and disease duration for comparison. The demographic information, the number of D4Z4 repeat units, the distal D4Z4 methylation levels, FSHD Clinical Score (CS), Clinical Severity Score (CSS), and Age-Corrected Clinical Severity Score (ACSS) of these patients were collected. Survival analysis was performed to compare the outcome of lower extremity involvement between late-onset and classic-onset FSHD1 patients. The correlation of the number of D4Z4 repeat units and D4Z4 methylation level with CS and ACSS was analyzed in late-onset FSHD1 patients.Results:A total of 61 patients with late-onset FSHD1 were enrolled, 33 (54.1%) of whom are female, with an age of 54.0 (46.0, 62.0) years and a disease duration of 14.0 (5.5, 22.5) years. Compared to classic-onset FSHD1 patients, late-onset patients exhibited significantly lower CS [7.0 (5.6, 8.4) vs 6.0 (4.4, 7.7), U=1 416.000, P=0.013], CSS [3.0 (2.8, 3.3) vs 3.0 (2.0, 4.0), U=2 352.000, P=0.010], and ACSS [189.2 (137.1, 241.3) vs 96.8 (61.3, 132.2), U=3 225.500, P0.001], and higher proportion of patients with limb girdle involvement but no facial muscle involvement [18.0% (11/61) vs 6.6% (4/61), χ2=3.725, P=0.054]. Kaplan-Meier survival analysis showed that the onset age of lower extremity involvement in late-onset patients (45 years, 95% CI 42-48 years) was significantly higher than that in classic-onset patients (24 years, 95% CI 21-27 years, χ2=61.012, P0.001). The duration from symptom onset to lower extremity involvement in late-onset patients (15 years, 95% CI 10-20 years) was significantly longer than that in classic-onset patients (8 years, 95% CI 3-13 years, χ2=9.105, P=0.003). Late-onset FSHD1 patients carried higher average distal D4Z4 methylation levels compared to those with classic-onset FSHD1 [46.68% (40.79%,52.57%) vs 41.02% (34.03%,48.00%), U=1 378.500, P=0.014]. Among late-onset FSHD1 patients, cytosine-phosphate-guanine 6 (CpG6) methylation levels were significantly negatively correlated with ACSS ( r=-0.278, P=0.025); the number of D4Z4 repeat units were significantly negatively correlated with ACSS ( r=-0.272, P=0.034);CpG6 methylation levels were significantly negatively correlated with CS ( r=-0.441, P=0.003), while no correlation was found between number of D4Z4 repeat units and CS ( r=-0.161, P=0.310). Conclusions:Compared with classic-onset FSHD1 patients, late-onset FSHD1 patients are associated with a higher degree of distal D4Z4 methylation, along with a milder muscle weakness phenotype, slower disease progression and a higher proportion of cases without facial muscle involvement. The age at onset can be used as a marker of the severity and prognosis in FSHD1.