Role of TRAK1 variants in epilepsy: genotype-phenotype analysis in a pediatric case of epilepsy with developmental disorder.

Purpose: The TRAK1 gene is mapped to chromosome 3p22.1 and encodes trafficking protein kinesin binding 1. The aim of this study was to investigate the genotype-phenotype of TRAK1-associated epilepsy. Methods: Trio-based whole-exome sequencing was performed on a cohort of 98 patients with epilepsy of unknown etiologies. Protein modeling and the VarCards database were used to predict the damaging effects of the variants. Detailed neurological phenotypes of all patients with epilepsy having TRAK1 variants were analyzed to assess the genotype-phenotype correlations. Results: A novel TRAK1 compound heterozygous variant comprising variant c.835C > T, p.Arg279Cys and variant c.2560A > C, p.Lys854Gln was identified in one pediatric patient. Protein modeling and VarCards database analyses revealed that the variants were damaging. The patient received a diagnosis of early infantile epileptic spasms with a developmental disorder; he became seizure-free through valproate and adrenocorticotropic hormone treatment. Further results for six variants in 12 patients with epilepsy indicated that biallelic TRAK1 variants (including homozygous or compound heterozygous variants) were associated with epilepsy with developmental disorders. Among these patients, eight (67%) had epileptic spasms and seven (58%) were intractable to anti-seizure medicines. Moreover, eight patients experienced refractory status epilepticus, of which seven (88%) died in early life. To our knowledge, this is the first reported case of epilepsy caused by TRAK1 compound heterozygous variants. Conclusion: Biallelic TRAK1 variants can cause epilepsy and developmental disorders. In these patients, seizures progress to status epilepticus, suggesting a high risk for poor outcomes and the requirement of early treatment.

Both epilepsy and anti-seizure medications affect bone metabolism in children with self-limited epilepsy with centrotemporal spikes.

OBJECTIVE: Bone metabolism can be influenced by a range of factors. We selected children with self-limited epilepsy with centrotemporal spikes (SeLECTS) and lifestyles similar to those of healthy children to control for the confounding factors that may influence bone metabolism. We aimed to identify the specific effects of epilepsy and/or anti-seizure medications (ASMs) on bone metabolism. METHODS: Patients with SeLECTS were divided into an untreated group and a monotherapy group, and the third group was a healthy control group. We determined the levels of various biochemical markers of bone metabolism, including procollagen type I nitrogenous propeptide (PINP), alkaline phosphatase (ALP), osteocalcin (OC), collagen type I cross-linked C-telopeptide (CTX), calcium, magnesium, phosphorus, parathyroid hormone (PTH), and vitamin D3 (VD3 ). RESULTS: A total of 1487 patients (from 19 centers) were diagnosed with SeLECTS; 1032 were analyzed, including 117 patients who did not receive any ASMs (untreated group), 643 patients who received only one ASM (monotherapy group), and 272 children in the healthy control group. Except for VD3 , other bone metabolism of the three groups were different (p < .001). Bone metabolism was significantly lower in the untreated group than the healthy control group (p < .05). There were significant differences between the monotherapy and healthy control group in the level of many markers. However, when comparing the monotherapy and untreated groups, the results were different; oxcarbazepine, levetiracetam, and topiramate had no significant effect on bone metabolism. Phosphorus and magnesium were significantly lower in the valproic acid group than the untreated group (adjusted p < .05, Cliff's delta .282-.768). CTX was significantly higher in the lamotrigine group than in the untreated group (adjusted p = .012, Cliff's delta = .316). SIGNIFICANCE: Epilepsy can affect many aspects of bone metabolism. After controlling epilepsy and other confounders that affect bone metabolism, we found that the effects of ASMs on bone metabolism differed. Oxcarbazepine, levetiracetam, and topiramate did not affect bone metabolism, and lamotrigine corrected some of the abnormal markers of bone metabolism in patients with epilepsy.

Investigation of FRMPD4 variants associated with X-linked epilepsy.

BACKGROUND: The etiology of unexplained epilepsy in most patients remains unclear. Variants of FRMPD4 are suggested to be associated with neurodevelopmental disorders. Therefore, we screened for disease-causing FRMPD4 variants in patients with epilepsy. METHODS: Trios-based whole-exome sequencing was conducted on a cohort of 85 patients with unexplained epilepsy, their parents, and extended family members. Additional cases with FRMPD4 variants were identified from the China Epilepsy Gene Matching Platform V.1.0. The frequency of variants was analyzed, and their subregional effects were predicted using in silico tools. The genotype-phenotype correlation of the newly defined causative genes and protein stability were analyzed using I-Mutant V.3.0 and Grantham scores. RESULTS: Two novel missense variants of FRMPD4 were identified in two families. Using the gene matching platform, we identified three additional novel missense variants. These variants presented at low or no allele frequencies in the gnomAD database. All the variants were located outside the three FRMPD4 main domains (WW, PDZ, and FERM). In silico analyses revealed that the variants were damaging and were predicted to be the least stable. All patients eventually became seizure-free. Eight of the 21 patients with FRMPD4 variants had epilepsy, of which five (63%) had missense variants located outside the domains, two had deletions involving exon 2, and one had a frameshift variant located outside the domains. Patients with epilepsy caused by missense variants were often free of intellectual disabilities (4/5), whereas patients with epilepsy caused by truncated variants had intellectual disabilities and structural brain abnormalities (3/3). CONCLUSIONS: The FRMPD4 gene is potentially associated with epilepsy. The genotype-phenotype correlation of FRMPD4 variants indicated that differences in variant types and locations of FRMPD4 may explain their phenotypic variation.

The increase of Nrf2 m6A modification induced by FTO downregulation promotes hippocampal neuron injury and aggravates the progression of epilepsy in a rat model.

Epilepsy is a common chronic neurological disorder characterized by widespread neuronal death. The purpose of this study was to investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) m6A methylation in epilepsy. To create epileptic models, the rats were given Lithium chloride and pilocarpine, and isolated primary rat hippocampal neurons were cultured in an Mg2+ -free medium. The frequency of seizures was recorded in the epilepsy group of rats. The functional tests included TUNEL, MTT, and flow cytometry. Mechanistically, RNA degradation assay, RNA immunoprecipitation, and methylated RNA immunoprecipitation were performed. In epileptic models, Nrf2 and fat mass and obesity-associated (FTO) levels were downregulated, whereas YT521-B homology (YTH) domain family protein 2 (YTHDF2) was upregulated. Additionally, in epileptic models, there was a rise in the m6A methylation level of Nrf2 mRNA. Overexpressing FTO increased cell viability and reduced apoptosis, but Nrf2 interference reversed these effects. Meanwhile, FTO overexpression decreased the m6A methylation of Nrf2 mRNA. Moreover, YTHDF2 bound to Nrf2 mRNA and decreased its stability. Furthermore, FTO overexpression reduced seizure frequency in rats and inhibited hippocampal neuron apoptosis via lowering the m6A methylation level of Nrf2 mRNA. Overexpressing FTO reduced m6A methylation of Nrf2 mRNA, increased cell viability, suppressed apoptosis, and slowed the progression of epileptic diseases, which is linked to YTHDF2 binding to m6A-modified Nrf2 and promoting its degradation, as well as downregulating Nrf2 expression in hippocampal neurons.

Phenotypic expansion of KCNH1-associated disorders to include isolated epilepsy and its associations with genotypes and molecular sub-regional locations.

PURPOSE: Genotype-phenotypic correlation of KCNH1 variant remains elusive. This study aimed to expand the phenotypic spectrum of KCNH1 and explore the correlations between epilepsy and molecular sub-regional locations. METHODS: We performed whole-exome sequencing in a cohort of 98 patients with familiar febrile seizure (FS) or epilepsy with unexplained etiologies. The damaging effects of variants were predicted by protein modeling and multiple in silico tools. All reported patients with KCNH1 pathogenic variants with detailed neurological phenotypes were analyzed to evaluate the genotype-phenotype correlation. RESULTS: Two novel KCNH1 variants were identified in three cases, including two patients with FS with inherited variant (p.Ile113Thr) and one boy with epilepsy with de novo variant (p.Arg357Trp). Variant Ile113Thr was located within the eag domain, and variant p.Arg357Trp was located in transmembrane domain 4 of KCNH1, respectively. Two patients experienced refractory status epilepticus (SE), of which one patient died of acute encephalopathy induced by SE. Further analysis of 30 variants in 51 patients demonstrated that de novo variants were associated with epileptic encephalopathy, while mosaic/somatic or germline variants cause isolated epilepsy/FS. All hotspot variants associated with epileptic encephalopathy clustered in transmembrane domain (S4 and S6), while those with isolated epilepsy/seizures or TBS/ZLS without epilepsy were scattered in the KCNH1. CONCLUSIONS: We found two novel missense variants of KCNH1 in three individuals with isolated FS/epilepsy. Variants in the KCNH1 cause a spectrum of epileptic disorders ranging from a benign form of genetic isolated epilepsy/FS to intractable form of epileptic encephalopathy. The genotypes and variant locations help explaining the phenotypic variation of patients with KCNH1 variant.

Weakness in both lower limbs for 1 week and blepharoptosis for 3 days in a boy aged 1 year and 7 months. / ç”·æ€§å¹¼å„¿åŒä¸‹è‚¢æ— åŠ›1周伴眼睑下垂3 d.

A boy, aged 1 year and 7 months, was hospitalized due to weakness in both lower limbs and blepharoptosis, which showed progressive aggravation and developed into irregular breathing. Neurological examinations showed lethargy, blepharoptosis, grade 4 muscle strength of both upper limbs, grade 3 muscle strength of both lower limbs, and disappearance of tendon reflex. Laboratory tests revealed albuminocytological dissociation in cerebrospinal fluid, disappearance of H reflex, and positive serum anti-GD1b IgG. The boy was finally diagnosed with Guillain-Barré syndrome (GBS) overlapping with Miller-Fisher syndrome and Bickerstaff brainstem encephalitis. He recovered and was discharged after treatment including immunoglobulin, plasma exchange, and respiratory support. The GBS overlap syndromes in children have strong clinical heterogeneity due to the injury of both peripheral nerve and brainstem, among which anti-GD1b antibody-related GBS overlap syndromes have special clinical manifestations and complex neuroelectrophysiological changes and are thus difficult to diagnose. Nerve conduction velocity tests, especially H reflex test, should be performed for children with weakness in both lower limbs and blepharoptosis.

[Progressive psychomotor regression for 2.5 years in a boy aged 5 years]. / 5岁男童进行性智力运动功能倒退2.5年.

A boy, aged 5 years, attended the hospital due to progressive psychomotor regression for 2.5 years. Motor function regression was the main manifestation in the early stage, and brain MRI and whole-exome sequencing (WES) of the family showed no abnormalities. After the age of 4 years and 9 months, the boy developed cognitive function regression, and brain MRI showed cerebellar atrophy. The reanalysis of WES results revealed a compound heterozygous mutation, [NM_000520, c.784C>T(p.His262Tyr]), c.1412C>T(p.Pro471Leu)], in the HEXA gene. The enzyme activity detection showed a significant reduction in the level of ß-hexosaminidase encoded by this gene. The boy was diagnosed with juvenile Tay-Sachs disease (TSD). TSD has strong clinical heterogeneity, and cerebellar atrophy may be an important clue for the diagnosis of juvenile TSD. The reanalysis of genetic data when appropriate based on disease evolution may improve the positive rate of WES.

[Fever for 2 months and disturbance of consciousness for 1 week in a preschool-aged girl].

Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation syndrome (ROHHADS) is a rare multi-system disease, and delayed diagnosis and treatment may lead to catastrophic cardiopulmonary complications. As far as we know, no patient with ROHHADS has been reported in China, and this article reports a child with ROHHADS to improve the awareness of this disease among clinicians. A girl, aged 3 years, had the clinical manifestations of rapid weight gain, fever, disturbance of consciousness, and convulsion. The physical examination showed a body weight of 20 kg, somnolence, irregular breathing, and stiff neck. She had increased blood levels of prolactin and follicle-stimulating hormone and hyponatremia. The lumbar puncture showed an increased intracranial pressure. The brain MRI and magnetic resonance venography showed symmetrical lesions in the periventricular region and venous thrombosis in the right transverse sinus and the superior sagittal sinus. The sleep monitoring showed hypopnea. The girl was finally diagnosed with ROHHADS and intracranial venous thrombosis. She recovered after symptomatic treatment including decreasing intracranial pressure, anticoagulation, and respiratory support. The possibility of ROHHADS should be considered for patients with unexplained obesity, fever, and hypoventilation, with or without central nervous system symptoms. Early diagnosis and standardized follow-up can improve the prognosis of children with ROHHADS.

[Hypertension and intermittent convulsions for one month in a school-age child].

Childhood polyarteritis nodosa (PAN) is a rare systemic vasculitis and the delayed diagnosis and treatment will cause high incidence of sequelae and high mortality. This article reports a girl with childhood PAN due to posterior reversible encephalopathy syndrome (PRES). The girl aged ten years was admitted to the hospital due to hypertension and convulsions for one month. She had complaints of headache, vomiting, and blurred vision before convulsions. At six months before admission, a mass was observed in the neck. The physical examination showed that she had hypertension and no abnormal findings in the central nervous system. The brain magnetic resonance imaging manifested long T1 and T2 signals, high signal intensities on fluid-attenuated inversion recovery (FLAIR) images, and iso-signal intensity on diffusion-weighted imaging in the white matter of the left occipital lobe. Therefore, the cause of convulsions was considered as PRES. Mass biopsy suggested PAN and no findings supported tuberculosis. The right kidney atrophy was observed by ultrasound examination. Emission computed tomography of the kidney showed multiple vascular stenosis and no blood perfusion in the right kidney, so PAN was confirmed. These findings suggest that PAN should be considered in patients with vasculitis who had involvements of multiple systems after excluding common vasculitis, such as Kawasaki disease and Henoch-Schönlein purpura. Biopsy and angiography should be performed as early as possible for timely diagnosis and treatment.

Clinical features of benign epilepsy of childhood with centrotemporal spikes in chinese children.

This multicenter clinical trial was conducted to examine current practice of benign epilepsy with centrotemporal spikes and especially address the question that in what circumstances 1 antiepileptic drug (AED) should be preferred.Twenty-five medical centers participate in this clinical trial. The general information, clinical information, and treatment status were collected under the guidance of clinicians and then analyzed. Difference between different treatment groups was compared, and usefulness of the most commonly used AEDs was evaluated.A total of 1817 subjects were collected. The average age of the subject was 8.81 years. The average age of onset is 6.85 years (1-14 years). Male-to-female ratio is 1.13:1. A total of 62.9% of the patients are receiving monotherapies, and 10.6% are receiving multidrug therapy. Both age and course of disease of treated rolandic epilepsy (RE) patients are significantly different from those of untreated patients. Bilateral findings on electroencephalography (EEG) are less seen in patients with monotherapy compared with patients with multidrug therapy. Except for 25.4% patients not taking any AEDs, oxcarbazepine (OXC), sodium valproate (VPA), and levetiracetam (LEV) are the most commonly used 3 AEDs. VPA and LEV are commonly used in add-on therapy. OXC and LEV are more effective as monotherapy than VPA.Age of onset of Chinese RE patients is 6.85 years. Bilateral findings on EEG could be a risk factor to require multidrug therapy. In Chinese patients, OXC, VPA, and LEV are most commonly used AEDs as monotherapy and OXC and LEV are more effective than VPA.

X-Linked Hereditary Motor Sensory Neuropathy Type 1 (CMTX1) in a Three-Generation Gelao Chinese Family.

In this report, we describe a three-generation family (the Gelao nationality, a minority ethnic group from Guizhou Province in the southwest China) with one affected member with Charcot-Marie-Tooth neuropathy X type 1 (CMTX1) in each generation. The three affected members carrying the R164W mutation in the Cx32 gene had different clinical symptoms. The proband, a 13-year-old boy presented recurrent episodes of transient central nervous system symptoms and concomitant transient diffuse white matter lesions on magnetic resonance imaging. His grandfather had the peripheral neurological presentations with later onset in the fourth decade, characterized by slowly progressive weakness of the distal muscles, atrophy, and foot deformities. But no sensory loss was observed. The proband's 38-year-old mother denied any neurological symptoms. The examination was normal except for pes cavus and diminished deep tendon reflexes in her lower limbs bilaterally. Genetic sequencing revealed the proband and his grandfather had a hemizygous mutation (p.164R > W) of CJB1 gene, and his mother had R164W heterozygous mutation. Our three cases denied symptoms of sensory disturbances, the sensory examination including touch, pin prick, and temperature sensation showed no obvious abnormalities. Thus, further investigation is needed to improve our understanding of the Cx32 protein function in the nervous system.

The characterization of childhood occipital epilepsy of Gastaut: a study of seven patients.

Characterization of the electroclinical features and evolution of childhood occipital epilepsy of Gastaut (COE-G). Seven children were retrospectively identified as having COE-G and were followed-up clinically using EEGs. Visual manifestations were the most common ictal event. Eye-associated ictal deviation was associated with ipsilateral turning of the head and migraine-like symptoms were frequent. Hemiconvulsions occurred in two children, and only one child had secondary generalized tonic-clonic seizures. In all patients, seizures occurred while awake, while two patients also had seizures while sleeping. EEG showed five patients with occipital spike-wave discharges when their eyes were closed which disappeared once their eyes were opened. Two cases continued having frequent seizures despite antiepileptic drug treatment. These patients also displayed learning difficulties and behavioral impairments after seizure onset. COE-G is a distinctive epileptic syndrome; however, the long-term prognosis for patients with the condition is unclear.

[Clinical and electroencephalographic features in children with benign occipital epilepsy].

OBJECTIVE: To study and compare the clinical and electroencephalography (EEG) features in children with benign occipital epilepsy (BOE) of Gastaut and Panayiotopoulos types. METHODS: The clinical data of 23 children with BOE (16 Gastaut type and 7 Panayiotopoulos type) were retrospectively studied. RESULTS: The mean age of onset in the Panayiotopoulos and Gastaut groups were 4.5 and 9.1 years, respectively. The children in the Panayiotopoulos group were characterized by ictal vomiting, frequent deviation of eyes and head, frequent nocturnal seizures, and secondary generalized seizures with longer duration but less frequency. By comparison, the children in the Gastaut group were characterized by visual symptoms as ictal events, higher seizure frequency, shorter seizure duration and more frequent diurnal seizures. The EEG showed that the majority of both groups had occipital spike-wave discharges when the eyes were opened. Eleven children in the Panayiotopoulos group and all of 7 children in the Gastaut group received antiepileptic mono-drug therapy. All of the 11 children in the Panayiotopoulos group responded to the therapy, but 2 cases in the Gastaut group did not respond and 2 cases had subtle cognitive deficits. CONCLUSIONS: There are differences in the age of onset, clinical symptoms, seizure frequency and duration, and therapeutic responses between children with Panayiotopoulos and Gastaut type BOE.

[A comparative study of conventional dose and low dose adrenocorticotrophic hormone therapy for West syndrome].

OBJECTIVE: The efficacy and adverse effects of conventional dose and low dose adrenocorticotrophic hormone (ACTH) therapy for West syndrome (WS) were compared in order to identify a low effective dose with few adverse effects. METHODS: A prospective randomized controlled study was conducted. Thirty children with cryptogenic (n=8) or symptomatic (n=22) WS were enrolled. They were randomly assigned to receive either conventional dose or low dose ACTH therapy. For the conventional dose group, ACTH 50 IU per day was administered for 2 weeks and tapered to zero over the subsequent 2 weeks. For the low dose group, 0.4 IU/kg per day was injected for 2 weeks. After seizures were fully controlled, ACTH was tapered to zero over the subsequent 2 weeks. If there was an absence of an effective response in the low dose group, the dosage was increased to 1 IU/kg per day for the next 2 weeks and then tapered to zero over 2 weeks. Both effectiveness and adverse effects were compared between the two groups. RESULTS: There were no significant differences in the good initial responses between the conventional and the low dose groups, which were 53% and 60%, respectively (P> 0.05). EEG findings after ACTH therapy, the rate of relapse of spasms, and the interval to relapse were not different between the two groups (P> 0.05). The long-term outcomes were assessed in the initial 8 responders, and there were no significant differences between the two groups (follow-up duration>12 months). The rates of good efficacy and disappearance of the hypsarrhythmia were significantly higher in the cryptogenic WS group than in the symptomatic WS group (P<0.05). The incidence of ACTH therapy related-adverse effects in the conventional dose group (93%) was significantly higher than in the low dose group (20%) (P<0.01). The mild brain shrinkage was observed in one patient from the conventional dose group. CONCLUSIONS: The short-term and long-term therapeutic effects of ACTH between 50 IU/d and 0.4 IU/kg/d doses are similar. ACTH therapy is more effective for cryptogenic WS than symptomatic WS. To reduce adverse effects, ACTH therapy should start with a low dose (0.4 IU/ kg each day).

Carbohydrate mimicry of Campylobacter jejuni lipooligosaccharide is critical for the induction of anti-GM1 antibody and neuropathy.

The expression of ganglioside-mimicking structures of Campylobacter jejuni lipooligosaccharides (LOS) is considered essential for the induction of antiganglioside antibodies that lead to Guillain-Barré syndrome (GBS). The galE gene in C. jejuni is involved in the biosynthesis of the LOS outer-core oligosaccharide structures. We have demonstrated that the C. jejuni HB9313 (HS:19) parental strain expresses a LOS structure containing GM1-like epitopes, and the C. jejuni knockout mutant of the galE gene expresses a truncated LOS structure without GM1-like epitopes. To clarify whether the ganglioside-like structures in Campylobacteri LOS are crucial for induction of antiganglioside antibody responses and neuropathy, we performed immunization experiments in guinea pig models using the parental strain HB9313 and its galE mutant derivative. The anti-GM1 IgG antibody responses in immunized animals were measured by enzyme-linked immunosorbent assay. Sciatic nerve specimens were evaluated pathologically. High levels of the anti-GM1 IgG antibody were induced in guinea pigs immunized with HB9313, but not in those immunized with the galE mutant. The mean percentage of abnormality of sciatic-nerve teased fibers from animals sensitized with C. jejuni HB9313 was significantly higher than from animals immunized with the galE mutant. Furthermore, significant changes were found in semithin sections of the sciatic nerve from animals inoculated with C. jejuni HB9313. The major pathological finding was axonal degeneration; no significant morphological findings, except for occasional demyelination, were observed in animals immunized with the galE mutant. These results indicate that ganglioside-mimicry structures in C. jejuni LOS are necessary for induction of antiganglioside antibody response and neuropathy.

[Comparative study on the role of parent Campylobacter jejuni and galE mutant in inducing experimental peripheral nerve damage].

OBJECTIVE: A comparative study on the role of Campylobacter jejuni (CJ) HB9313 and galE mutant in inducing experimental sciatic nerve damage was conducted in guinea pigs in order to explore whether CJ lipo-oligosaccharide (LOS) is critical component associated with peripheral nerve lesions and find experimental evidence for the presumption of molecular mimicry on the pathogenesis of Guillain-Barre syndromes (GBS) with CJ antecedent infection. METHODS: A total of 32 guinea pigs were randomly divided into four groups: parental strain group (n = 10), galE mutant group (n = 10), control group (n = 6) and PBS group (n = 6), and immunized with the whole cell antigens of CJ HB9313 with Freund's adjuvant (FA), the whole cell antigens of galE mutant (without ganglioside-like structure) with FA, PBS with FA, and PBS alone, respectively. Enzyme-linked immunosorbent assay (ELISA) was employed to detect anti-LOS and anti-ganglioside GM1 antibodies in sera of these animals, and comparative morphologic studies of pathologic changes were carried out on the sciatic nerves, including examination of teasing fibers, examination of semithin sections made from epon-embedded tissue blocks under light microscope and transmission electron microscope. RESULTS: ELISA results indicated that after immunization, the levels of anti-LOS IgG antibody were significantly elevated in animals from parental strain group and galE mutant group as compared with those before immunization (P < 0.01). No statistically significant difference was found between the two groups. However, the mean optical densities (ODs) of IgG antibody against GM1 at 14 and 28 day after immunization, in parental strain group, were 0.661 +/- 0.290 and 0.984 +/- 0.025, respectively, significantly higher than those of galE mutant group, which were 0.193 +/- 0.078 and 0.180 +/- 0.063 (P < 0.01). The results of morphologic examination on sciatic nerves showed that for teased-fiber study, incidence of pathologic abnormalities of teased fibers from animals of galE mutant group was 4.9% (98/2000), significantly lower than that from parental strain group, which was 16% (320/2000), characterized by predominantly axonal degeneration. The difference between them was highly significant statistically (P < 0.01). Examination of semithin sections of sciatic nerves also revealed that obvious pathological changes occurred in the animals from parental strain group, while only minimal abnormalities could be seen from galE mutant group, there was a significant differences between them (P < 0.01). In parental strains group, the predominant pathologicanl change was axonal degeneration with considerable variation in severity. These morphologic changes were confirmed by electron microscopy. CONCLUSION: Compared with parental strain, galE mutant without ganglioside-like structure no longer could induce anti-GM1 antibodies, nor induce obvious immune damage of peripheral nerves in experimental guinea pigs. The results of this study provide a strong support to the hypothesis of molecular mimicry as a pathogenesis in patients with GBS following CJ antecedent infection.