Objective To investigate the expression and role of T cell immunoglobulin and mucin domain-containing protein 3(Tim-3)in the pathogenesis of experimental autoimmune uveitis(EAU).Methods A total of 12 male C57BL/6J mice,aged 4 to 5 weeks,were selected and divided into the control group(n=3)and the experimental group(n=9)using a random number table.The control group(modeling time point:0 days after modeling)received no treatment,while the experimental group was induced to establish an EAU model(divided into three subgroups according to the modeling time points:7 days,14 days,and 21 days after modeling,with 3 mice in each subgroup).Firstly,the interphotoreceptor retinoid-binding protein 651-670 and complete Freund's adjuvant were fully mixed and emulsified.Then,the emulsion was subcutaneously injected into the two thighs,tail base,and neck of mice in the experimental group(each mouse received 200 μL of immune emulsion containing 500 pg of interphotoreceptor retinoid-binding protein 651-670).Subsequently,each mouse in the experimental group was also intraperitoneally injected with 1 μg of pertussis toxin.The anterior segment and fundus of mice in each group were observed and photographed under a slit-lamp microscope.The clinical and histopatho-logical scoring of these mice was conducted according to the Caspi grading scale based on the severity of inflammation.The serum levels of IFN-γ and IL-17 were measured using the enzyme-linked immunosorbent assay(ELISA),while the mRNA expression of Tim-3 in the spleen and ocular tissues was detected using the real-time quantitative polymerase chain reaction(RT-qPCR).Western blot was employed to detect the protein expression of Tim-3,and immunohistochemistry was used to examine the protein expression of Tim-3 in the spleen tissue.Statistical analysis was performed using GraphPad Prism 9.0.Results The clinical scores of the anterior segment,fundus,and histopathology of the mice increased over time after modeling,with statistically significant differences among these groups(P＜0.05).The serum levels of IFN-γ and IL-17 in the mice also increased over time after modeling,with statistically significant differences among these groups(P＜0.05).The relative mRNA expression of Tim-3 in the spleen and ocular tissues of the mice decreased over time after modeling,with statistically significant differences among these groups(P＜0.05).The protein expression of Tim-3 in the ocular and spleen tissues showed the same pattern as its mRNA expression.Conclusion The expression of Tim-3 decreases with the exacerbation of inflammation in the progression of EAU,suggesting that Tim-3 may play a negative immunoregulatory role in the development of uveitis.

Objective To investigate the expression and mechanistic role of the M2-type pyruvate kinase(PKM2)/signal transducer and activator of transcription 3(STAT3)signaling pathway in the development of experimental autoim-mune uveitis(EAU).Methods Eighteen 4-to 5-week-old C57BL/6J mice were selected and randomly divided into a control group(normal breeding,set as the 0-day state post-modeling),Experimental Group A,and Experimental Group B(both established as stable EAU mouse models using the interphotoreceptor retinoid-binding protein peptide 651-670,com-plete Freund's adjuvant,and pertussis toxin,designated as the 14-day and 21-day states post-modeling,respectively),with 6 mice in each group.The anterior segment of the mice was observed using a slit-lamp microscope,fundus findings were collected using a fundus camera,and clinical and histopathological scores were evaluated after hematoxylin-eosin stai-ning.The protein expression level of serum interleukin(IL)-17A was detected by ELISA.The expression level of PKM2 protein in retinal tissue was detected by immunohistochemistry.The protein expression levels of PKM2,phosphorylated STAT3(p-STAT3),and STAT3 in mouse retinal tissue were detected by Western blot.Results The clinical scores of the anterior segment and fundus,as well as the retinal histopathological scores in Experimental Group A and Experimental Group B,were all significantly higher than those in the control group(all P＜0.05).The serum IL-17A protein expression levels in the control group,Experimental Group A,and Experimental Group B were(69.05±0.45)ng·L-1,(75.06±0.46)ng·L-1,and(72.04±0.82)ng·L-1,respectively.The optical density values of PKM2 protein expression in retinal tissue were(18.51±2.59)％,(37.35±4.67)％,and(29.75±2.17)％,respectively.The expression levels of serum IL-17A protein,retinal PKM2 protein,and retinal STAT3 and p-STAT3 proteins in Experimental Group A and Experimental Group B were all significantly higher than those in the control group(all P＜0.05).Conclusion The expression levels of key factors in the PKM2/STAT3 signaling pathway are positively correlated with the severity of EAU,indicating that this sig-naling pathway,as a positive regulator of the immune response,is involved in the pathological process of EAU.

Objective To investigate the expression and role of T cell immunoglobulin and mucin domain-containing protein 3(Tim-3)in the pathogenesis of experimental autoimmune uveitis(EAU).Methods A total of 12 male C57BL/6J mice,aged 4 to 5 weeks,were selected and divided into the control group(n=3)and the experimental group(n=9)using a random number table.The control group(modeling time point:0 days after modeling)received no treatment,while the experimental group was induced to establish an EAU model(divided into three subgroups according to the modeling time points:7 days,14 days,and 21 days after modeling,with 3 mice in each subgroup).Firstly,the interphotoreceptor retinoid-binding protein 651-670 and complete Freund's adjuvant were fully mixed and emulsified.Then,the emulsion was subcutaneously injected into the two thighs,tail base,and neck of mice in the experimental group(each mouse received 200 μL of immune emulsion containing 500 pg of interphotoreceptor retinoid-binding protein 651-670).Subsequently,each mouse in the experimental group was also intraperitoneally injected with 1 μg of pertussis toxin.The anterior segment and fundus of mice in each group were observed and photographed under a slit-lamp microscope.The clinical and histopatho-logical scoring of these mice was conducted according to the Caspi grading scale based on the severity of inflammation.The serum levels of IFN-γ and IL-17 were measured using the enzyme-linked immunosorbent assay(ELISA),while the mRNA expression of Tim-3 in the spleen and ocular tissues was detected using the real-time quantitative polymerase chain reaction(RT-qPCR).Western blot was employed to detect the protein expression of Tim-3,and immunohistochemistry was used to examine the protein expression of Tim-3 in the spleen tissue.Statistical analysis was performed using GraphPad Prism 9.0.Results The clinical scores of the anterior segment,fundus,and histopathology of the mice increased over time after modeling,with statistically significant differences among these groups(P＜0.05).The serum levels of IFN-γ and IL-17 in the mice also increased over time after modeling,with statistically significant differences among these groups(P＜0.05).The relative mRNA expression of Tim-3 in the spleen and ocular tissues of the mice decreased over time after modeling,with statistically significant differences among these groups(P＜0.05).The protein expression of Tim-3 in the ocular and spleen tissues showed the same pattern as its mRNA expression.Conclusion The expression of Tim-3 decreases with the exacerbation of inflammation in the progression of EAU,suggesting that Tim-3 may play a negative immunoregulatory role in the development of uveitis.

Objective To investigate the expression and mechanistic role of the M2-type pyruvate kinase(PKM2)/signal transducer and activator of transcription 3(STAT3)signaling pathway in the development of experimental autoim-mune uveitis(EAU).Methods Eighteen 4-to 5-week-old C57BL/6J mice were selected and randomly divided into a control group(normal breeding,set as the 0-day state post-modeling),Experimental Group A,and Experimental Group B(both established as stable EAU mouse models using the interphotoreceptor retinoid-binding protein peptide 651-670,com-plete Freund's adjuvant,and pertussis toxin,designated as the 14-day and 21-day states post-modeling,respectively),with 6 mice in each group.The anterior segment of the mice was observed using a slit-lamp microscope,fundus findings were collected using a fundus camera,and clinical and histopathological scores were evaluated after hematoxylin-eosin stai-ning.The protein expression level of serum interleukin(IL)-17A was detected by ELISA.The expression level of PKM2 protein in retinal tissue was detected by immunohistochemistry.The protein expression levels of PKM2,phosphorylated STAT3(p-STAT3),and STAT3 in mouse retinal tissue were detected by Western blot.Results The clinical scores of the anterior segment and fundus,as well as the retinal histopathological scores in Experimental Group A and Experimental Group B,were all significantly higher than those in the control group(all P＜0.05).The serum IL-17A protein expression levels in the control group,Experimental Group A,and Experimental Group B were(69.05±0.45)ng·L-1,(75.06±0.46)ng·L-1,and(72.04±0.82)ng·L-1,respectively.The optical density values of PKM2 protein expression in retinal tissue were(18.51±2.59)％,(37.35±4.67)％,and(29.75±2.17)％,respectively.The expression levels of serum IL-17A protein,retinal PKM2 protein,and retinal STAT3 and p-STAT3 proteins in Experimental Group A and Experimental Group B were all significantly higher than those in the control group(all P＜0.05).Conclusion The expression levels of key factors in the PKM2/STAT3 signaling pathway are positively correlated with the severity of EAU,indicating that this sig-naling pathway,as a positive regulator of the immune response,is involved in the pathological process of EAU.

Objective:To explore the diagnosis and treatment of adolescence-onset methylenetetrahydrofolate reductase (MTHFR) deficiency.Methods:This was a retrospective case study. Nine patients with adolescence-onset MTHFR deficiency were diagnosed at Peking University First Hospital from January 2016 to December 2022, and followed up for more than 1 year. Their general information, clinical manifestations, laboratory tests, cranial images, MTHFR gene variants, diagnosis, treatment, and outcome were analyzed retrospectively.Results:The 9 patients came from 8 families. They had symptoms at age of 8.0 years to 17.0 years and diagnosed at 9.0 years to 17.5 years. Eight were male and 1 was female. Two patients were brothers, the elder brother developed abnormal gait at 17.0 years; and the younger brother was then diagnosed at 15.0 years of age and treated at the asymptomatic stage, who was 18.0 years old with normal condition during this study. The main manifestations of the 8 symptomatic patients included progressive dyskinesia and spastic paralysis of the lower limbs, with or without intellectual decline, cognitive impairment and behavioral abnormalities. Totally, 15 variants of MTHFR gene were identified in the 9 patients, including 8 novel variants. Five patients had brain image abnormalities. Increased plasma total homocysteine level (65-221 μmol/L) was found in all patients, and decreased to 20-70 μmol/L after treatment with betaine and calcium folinate. Besides, the 8 symptomatic patients had their behavior and cognitive problems significantly improved, with a legacy of lower limb motor disorders.Conclusions:Late-onset MTHFR deficiency can occur in adolescence. The diagnosis is usually delayed because of non-specific clinical symptoms. The test of blood total homocysteine could be used as a selective screening test. Eight novel varients of MTHFR gene were identified. Timely treatment can improve clinical condition significantly, and pre-symptomatic treatment may prevent brain damage.

Objective:To investigate the clinical features and outcomes of adolescence-onset methylmalonic acidemia (MMA) and explore preventive strategies.Methods:This was a retrospective case analysis of the phenotypes, genotypes and prognoses of adolescence-onset MMA patients. There were 55 patients diagnosed in Peking University First Hospital from January 2002 to June 2023, the data of symptoms, signs, laboratory results, gene variations, and outcomes was collected. The follow-ups were done through WeChat, telephone, or clinic visits every 3 to 6 months.Results:Among the 55 patients, 31 were males and 24 were females. The age of onset was 12 years old (range 10-18 years old). They visited clinics at Tanner stages 2 to 5 with typical secondary sexual characteristics. Nine cases (16%) were trigged by infection and 5 cases (9%) were triggered by insidious exercises. The period from onset to diagnosis was between 2 months and 6 years. Forty-five cases (82%) had neuropsychiatric symptoms as the main symptoms, followed by cardiovascular symptoms in 12 cases (22%), kidney damage in 7 cases (13%), and eye disease in 12 cases (22%). Fifty-four cases (98%) had the biochemical characteristics of methylmalonic acidemia combined with homocysteinemia, and 1 case (2%) had the isolated methylmalonic acidemia. Genetic diagnosis was obtained in 54 cases, with 20 variants identified in MMACHC gene and 2 in MMUT gene. In 53 children with MMACHC gene mutation,1 case had dual gene variants of PRDX1 and MMACHC, with 105 alleles. The top 5 frequent variants in MMACHC were c.482G>A in 39 alleles (37%), c.609G>A in 17 alleles (16%), c.658_660delAAG in 11 alleles (10%), c.80A>G in 10 alleles (10%), c.567dupT and c.394C>T both are 4 alleles (4%). All patients recovered using cobalamin, L-carnitine, betaine, and symptomatic therapy, and 54 patients (98%) returned to school or work.Conclusions:Patients with adolescence-onset MMA may triggered by fatigue or infection. The diagnosis is often delayed due to non-specific symptoms. Metabolic and genetic tests are crucial for a definite diagnosis. Treatment with cobalamin, L-carnitine, and betaine can effectively reverse the prognosis of MMA in adolescence-onset patients.

Objective:To investigate the factors affecting phenotypes in the patients of methylmalonic acidemia combined with homocysteinemia cblC type with MMACHC c. 609G>A homologous variant. Methods:A retrospective study on the clinical manifestations, complications, treatment, and outcome in 164patients of cblC type with MMACHC c. 609G>A homologous variant was conducted.The patients were diagnosed by biochemical and genetic analysisfrom January 1998 to December 2020. Results:Among the 164 patients, 2 cases were prenatally diagnosed and began treatment after birth. They are 3 and 12 years old with normal physical and mental development. Twenty-one cases were diagnosed by newborn screening. Among them, 15 cases had with normal development. They were treated fromthe age of two weeks at the asymptomatic period. Six cases began treatment aged 1 to 3 months after onset. Their development was delayed. One hundred and forty-one cases were clinically diagnosed. Their onset age ranges from a few minutes after birth to 6 years old. 110 cases had early-onset (78.0%). 31 cases had late-onset (22.0%). Five of them died. 24 patients lost to follow-up. Of the 141 clinically diagnosed patients, 130 (92.2%) with psychomotor retardation, 69 (48.9%) with epilepsy, 39 (27.7%) with anemia, 30 (21.3%) had visual impairment, 27 (19.1%) had hydrocephalus, 26 (18.4%) had feeding difficulties, 7 (5.0%) with liver damage, and 5 (3.5%) with metabolic syndrome. The frequency of hydrocephalus and seizures was significantly higher in the early-onset group. The urinary methylmalonic acid increased significantly in the patients with epilepsy. During the long-term follow-up, the level of plasma total homocysteine in the seizure-uncontrolled group was significantly higher than that in the seizure-controlled group, the difference had a statistical significance ( P<0.05). Conclusion:Most of the patients with MMACHC c. 609G>A homozygous variant had early-onset disease, with a high mortality and disability rate. If not treated in time, it will lead to neurological damage, resulting in epilepsy, mental retardation, hydrocephalus, and multiple organ damage. Pre-symptomatic diagnosis and treatment are crucial to prevent irreversible neurological damage. Neonatal screening and prenatal diagnosis are important to improve the outcome of the patients.

Objective:To analyze the clinical features, genetic characteristics, treatment and follow-up results of patients with hydrocephalus caused by methylmalonic acidemia combined with homocysteinuria, and to discuss the optimal strategies for assessing and treating such patients.Methods:From January 1998 to December 2020, 76 patients with hydrocephalus due to methylmalonic acidemia combined with homocysteinuria in the Department of Pediatrics in 11 hospitals including Peking University First Hospital were diagnosed by biochemical, genetic analysis and brain imaging examination. The patients were divided into operation-group and non-operation-group according to whether they underwent ventriculoperitoneal shunt. The clinical features, laboratory examinations, genotype, and follow-up data were retrospectively analyzed. Data were compared between the two groups using rank sum test, and categorical data were compared using χ 2 test. Results:Among the 76 patients (51 male, 25 female), 5 were detected by newborn screening, while 71 were diagnosed after clinical onset, 68 cases (96%) had early-onset, 3 cases (4%) had late-onset. The most common clinical manifestations of 74 cases with complete data were psychomotor retardation in 74 cases (100%), visual impairment in 74 cases (100%), epilepsy in 44 cases (59%), anemia in 31 cases (42%), hypotonia or hypertonia in 21 cases (28%), feeding difficulties in 19 cases (26%) and disturbance of consciousness in 17 cases (23%). Genetic analysis was performed in 76 cases, all of whom had MMACHC gene variations, including 30 homozygous variations of MMACHC c.609G>A. The most common variations were c.609G>A (94, 62.7%), followed by c.658_660del (18, 12.0%), c.567dupT (9, 6.0%) and c.217C>T (8, 5.3%). Therapy including cobalamin intramuscular injection, L-carnitine and betaine were initiated immediately after diagnosis. A ventriculoperitoneal shunt operation was performed in 41 cases (operation group), and 31 patients improved after metabolic intervention (non-operation group). There was no significant difference in the age of onset, the age of diagnosis, the blood total homocysteine, methionine, and urinary methylmalonic acid concentration between the two groups (all P>0.05). The symptoms of psychomotor development, epilepsy, and visual impairments improved gradually after a long-term follow-up in the operation group. Conclusions:Hydrocephalus is a severe complication of methylmalonic acidemia combined with homocysteinuria. The most common clinical manifestations are psychomotor retardation, visual impairment, and epilepsy. It usually occurs in early-onset patients. Early diagnosis and etiological treatment are very important. Hydrocephalus may improve after metabolic intervention in some patients. For patients with severe ventricular dilatation, prompt surgical intervention can improve the prognosis.

Objectives:To summarize the clinical and genetic characteristics of the patients with isolated methylmalonic acidemia and investigate the strategies for the diagnosis, treatment and prevention.Methods:Three hundred and fourteen patients (180 males, 134 females) with isolated methylmalonic acidemia were ascertained from 26 provinces or cities across the mainland of China during January 1998 to March 2020. Genetic analysis was performed by Sanger sequencing, gene panel sequencing, whole exome sequencing, multiplex ligation-dependent probe amplification or quantitative PCR. According to the age of onset, the patients were divided to early-onset group (≤12 months of age) and the late-onset group (>12 months of age). They were treated by cobalamin, L-carnitine and (or) special diet and symptomatic treatment. Statistical analysis was done using Chi-square test.Results:Fifty-eight of 314 (18.5%) patients were detected by Newborn screening using liquid chromatography tandem mass spectrometry. Five cases (1.6%) had a postmortem diagnosis. Two hundred and fifty-one patients (79.9%) were clinically diagnosed with an age of onset ranged from 3 hours after birth to 18 years. One hundred and fifty-nine patients (71.0%) belonged to early-onset groups, 65 patients (29.0%) belonged to the late-onset group. The most common symptoms were metabolic crises, psychomotor retardation, epilepsy, anemia and multiple organ damage. Metabolic acidosis and anemia were more common in early-onset patients than that in late-onset patients (20.8%(33/159) vs. 9.2% (6/65), 34.6% (55/159) vs. 16.9% (11/165), χ 2=4.261, 6.930, P=0.039, 0.008). Genetic tests were performed for 236 patients (75.2%), 96.2%(227/236) had molecular confirmation. One hundred and twenty-seven variants were identified in seven genes (MMUT, MMAA, MMAB, MMADHC, SUCLG1, SUCLA2, and MCEE), of which 49 were novel. The mut type, caused by the deficiency of methylmalonyl-CoA mutase, was the most common ( n=211, 93%) cause of this condition. c.729_730insTT, c.1106G>A and c.914T>C were the three most frequent mutations in MMUT gene. The frequency of c.914T>C in early-onset patients was significantly higher than that in late-onset patients (8.3% (18/216) vs. 1.6% (1/64), χ 2=3.859, P=0.037). Metabolic crisis was more frequent in mut type than the other types (72.6% (114/157) vs. 3/13, χ 2=13.729, P=0.001),developmental delay and hypotonia were less frequent in mut type (38.2% (60/157) vs. 9/13, 25.5% (40/157) vs. 8/13, χ 2=4.789, 7.705, P=0.030, 0.006). Of the 58 patients identified by newborn screening, 44 patients (75.9%) who were treated from asymptomatic phase developed normally whereas 14 patients (24.1%) who received treatment after developing symptoms exhibited varying degrees of psychomotor retardation. Conclusions:The characteristics of phenotypes and genotypes among Chinese patients with isolated methylmalonic acidemia were analyzed. Expanded the mutation spectrum of the associated genes. Because of the complex clinical manifestations and severe early onset of isolated methylmalonic acidemia, Newborn screening is crucial for early diagnosis and improvement of prognosis. MMUT gene is recommended for carrier screening as an effort to move the test earlier as a part of the primary prevention of birth defects.

Objective: To analyz the current situation of the diagnosis, treatment and prevention of methylmalonic acidemia, the phenotypes, biochemical features and genotypes of the patients in the mainland of China, were investigated. Methods: Tottally 1 003 patients of methylmalonic acidemia from 26 provinces and municipalities of the mainland of China were enrolled. The clinical data, biochemical features and gene mutations were studied. Blood aminoacids and acylcarnitines, urine organic acids, and plasma total homocysteine were determined for the biochemical diagnosis. Gene analyses were performed for the genetic study of 661 patients. The patients were treated with individual intervention and long-term follow up. Prenatal diagnoses were carried out for 165 fetuses of the families. Results: Among 1 003 patients (580 boys and 423 girls), 296 cases (29.5%) had isolated methylmalonic acidemia; 707 cases (70.5%) had combined homocysteinemia; 59 patients (5.9%) were detected by newborn screening; 944 patients (94.1%) had the onset at the ages from several minutes after birth to 25 years and diagnosed at 3 days to 25 years of age. The main clinical presentations were psychomotor retardation and metabolic crisis. Multi-organ damage, including hematological abnormalities, pulmonary hypertension, kidney damage, were found. MMACHC, MUT, MMAA, MMAB, HCFC1, SUCLG1, SUCLA2 mutations were found in 631 patients (96.6%) out of 661 patients who accepted gene analysis. MMACHC mutations were detected in 460 patients (94.7%) out of 486 cases of methylmalonic acidemia combined with homocysteinemia. MUT mutations were found in 158 (90.3%) out of 169 cases of isolated methylmalonic acidemia. The development of 59 patients detected by newborn screening were normal; 918 cases (97.2%) were diagnosed after onset accepted the treatment. Forty-five of them completely recovered with normal development. Twenty-six patients (2.7%) died; 873 (92.5%) patients had mild to severe psychomotor retardation. Methylmalonic acidemia were found in 35 out of 165 fetuses by metabolites assay of amniotic fluid and amniocytes gene analysis. Conclusion Combined methylmalonic acidemia and homocysteinemia is the common type of methylmalonic acidemia in the mainland of China. CblC defect due to MMACHC mutations is the most common type of methylmalonic acidemia combined with homocysteinemia. MUT gene mutations are frequent in the patients with isolated methylmalonic acidemia. Newborn screening is key for the early diagnosis and the better outcome. Combined diagnosis of biochemical assays and gene analysis are reliable for the prenatal diagnosis of methylmalonic acidemia.