Visual function in children with Joubert syndrome.

AIM: To describe visual function in children with Joubert syndrome and to investigate its possible association with diagnostic and developmental aspects. METHOD: This retrospective cross-sectional work included 59 patients (33 male; mean age 9 years 2 months, standard deviation 6 years 3 months, range 4 months to 23 years) diagnosed with Joubert syndrome from January 2002 to December 2020. Data about clinical (neurological, neuro-ophthalmological, developmental/cognitive) and diagnostic (e.g. genetic testing, neuroimaging, systemic involvement) evaluations were collected in a data set during a review of medical records. Clinical and diagnostic variables were described in terms of raw counts and percentages. A χ2 test was conducted to investigate their association with neuropsychological skills. RESULTS: Ocular motor apraxia was highly represented in our cohort (75%), with a high prevalence of refractive defects and retinal abnormalities. Developmental delay/intellectual disability was frequent (in 69.5% of the sample), associated with retinal dystrophy (p = 0.047) and reduced visual acuity both for near (p = 0.014) and for far distances (p = 0.017). INTERPRETATION: On the basis of the relevance of oculomotor and perceptual alterations and their impact on overall and cognitive impairment, we encourage early and multidisciplinary assessment and follow-up of visual function in children with Joubert syndrome. This would help in planning a personalized rehabilitation to sustain functional vision. Further studies will be important to explore the link between biological aspects and global functioning in children with Joubert syndrome. WHAT THIS PAPER ADDS: Perceptual deficits and oculomotor impairments frequently coexist in Joubert syndrome. Retinal dysfunction may be present despite the absence of funduscopic abnormalities. Both perceptual and oculomotor impairments negatively affect cognitive development in Joubert syndrome.

Ocular Manifestations Leading to a Diagnosis of Joubert Syndrome Related Disorder.

INTRODUCTION: Joubert syndrome is an inherited disorder of rare occurrence usually presenting as developmental delay, hypotonia, hyperpnea and ataxia. The diagnosis is confirmed by characteristic findings in neuroimaging. Involvement of ocular, renal and hepatic systems can be present. Joubert syndrome presenting first to an ophthalmologist is very uncommon. CASE: A twenty-one-year female, with history of delayed milestones, infantile hemiplegia with hearing and visual impairment was referred for visual assessment. On systemic examination, ataxic gait was present. CT head showed hypoplasia of postero-inferior portion of vermis with communication between 4th ventricle and cisterna magna with variable degree of cerebellar dysgenesis. The neurological, ophthalmological and radiological findings of this patient were consistent with Joubert syndrome related disorder. CONCLUSION: We hereby report a case of Joubert syndrome related disorder with ocular involvement which after correlation with neurological findings and neuroimaging led us to the diagnosis of this rare disorder. The renal and hepatic functions in these patients need to be monitored.

Congenital monocular elevation deficiency associated with a novel TUBB3 gene variant.

BACKGROUND: The genetic basis of monocular elevation deficiency (MED) is unclear. It has previously been considered to arise due to a supranuclear abnormality. METHODS: Two brothers with MED were referred to Leicester Royal Infirmary, UK from the local opticians. Their father had bilateral ptosis and was unable to elevate both eyes, consistent with the diagnosis of congenital fibrosis of extraocular muscles (CFEOM). Candidate sequencing was performed in all family members. RESULTS: Both affected siblings (aged 7 and 12 years) were unable to elevate the right eye. Their father had bilateral ptosis, left esotropia and bilateral limitation of elevation. Chin up head posture was present in the older sibling and the father. Bell's phenomenon and vertical rotational vestibulo-ocular reflex were absent in the right eye for both children. Mild bilateral facial nerve palsy was present in the older sibling and the father. Both siblings had slight difficulty with tandem gait. MRI revealed hypoplastic oculomotor nerve. Left anterior insular focal cortical dysplasia was seen in the older sibling. Sequencing of TUBB3 revealed a novel heterozygous variant (c.1263G>C, p.E421D) segregating with the phenotype. This residue is in the C-terminal H12 α-helix of ß-tubulin and is one of three putative kinesin binding sites. CONCLUSION: We show that familial MED can arise from a TUBB3 variant and could be considered a limited form of CFEOM. Neurological features such as mild facial palsy and cortical malformations can be present in patients with MED. Thus, in individuals with congenital MED, consideration may be made for TUBB3 mutation screening.

Changes in ocular motility in Kabuki syndrome. / Alteraciones de la motilidad ocular en el síndrome de Kabuki.

Kabuki syndrome is a rare genetic disorder, caused by mutation in the KMT2D or KDM6A genes, which affects several organs in the majority of patients, among which are the eyes. The most typical clinical characteristics are mental retardation, postnatal growth retardation, skeletal anomalies, and characteristic facial features. As the eyes are affected in most of the cases, ophthalmological examination is recommended for the early detection of ocular anomalies, in order to prevent visual impairment. The most frequent ocular signs are strabismus, ptosis, and refractive anomalies. A series of cases of Kabuki syndrome is described in five children, four of whom exhibited strabismus with esotropia, over action of inferior oblique muscles, and under action of superior oblique muscles associated with a V pattern. Most published papers do not report or might underestimate the ocular problems. It may be appropriate to perform orbital magnetic resonances in order to detect changes in the muscle paths that are related to the pathology of the eye movements found.

Ophthalmic manifestations in patients with Leigh syndrome, French Canadian type.

BACKGROUND: Leigh syndrome, French Canadian type is a rare neurodegenerative disease. To our knowledge, there have been no studies based on ocular findings published for this disease. The purpose of this study is to describe ophthalmic findings in these patients. PATIENTS: Six patients genetically identified as having the syndrome were included in this study. METHODS: Four patients had an ophthalmic examination with an ophthalmologist including evaluation of visual acuity, extraocular motility and lid position, orthoptic workup, evaluation of stereopsis, refraction, evaluation of pupils, color vision, slit-lamp biomicroscopy, measurement of intraocular pressure, and fundoscopy. Two patients had a chart review. RESULTS: Visual acuity ranged from 0.00 logmar to 1.55 logmar. Extraocular motility abnormalities and ptosis were noted in half of the patients. Strabismus was present in the entire cohort, and stereopsis was absent in half of these patients. Amblyopia was noted in 83% of individuals and suppression in 33%. Only one patient had nystagmus. Refraction varied throughout patients. It included severe hyperopia, myopia, astigmatism, and significant anisometropia. Pupils, anterior segment, fundus, and color vision were normal in all patients. Intraocular pressure was slightly elevated in one patient. CONCLUSION: Patients with Leigh syndrome, French Canadian type display a variety of ophthalmic findings, and screening at a young age is recommended.

Joubert Syndrome: Ophthalmological Findings in Correlation with Genotype and Hepatorenal Disease in 99 Patients Prospectively Evaluated at a Single Center.

PURPOSE: Joubert syndrome (JS) is caused by mutations in >34 genes that encode proteins involved with primary (nonmotile) cilia and the cilium basal body. This study describes the varying ocular phenotypes in JS patients, with correlation to systemic findings and genotype. DESIGN: Patients were systematically and prospectively examined at the National Institutes of Health (NIH) Clinical Center in the setting of a dedicated natural history clinical trial. PARTICIPANTS: Ninety-nine patients with JS examined at a single center. METHODS: All patients underwent genotyping for JS, followed by complete age-appropriate ophthalmic examinations at the NIH Clinical Center, including visual acuity (VA), fixation behavior, lid position, motility assessment, slit-lamp biomicroscopy, dilated fundus examination with an indirect ophthalmoscope, and retinoscopy. Color and fundus autofluorescence imaging, Optos wide-field photography (Dunfermline, Scotland, UK), and electroretinography (ERG) were performed when possible. MAIN OUTCOME MEASURES: The VA (with longitudinal follow-up where possible), ptosis, extraocular muscle function, retinal and optic nerve status, and retinal function as measured by ERG. RESULTS: Among patients with JS with quantifiable VA (68/99), values ranged from 0 logarithm of the minimum angle of resolution (logMAR) (Snellen 20/20) to 1.5 logMAR (Snellen 20/632). Strabismus (71/98), nystagmus (66/99), oculomotor apraxia (60/77), ptosis (30/98), coloboma (28/99), retinal degeneration (20/83), and optic nerve atrophy (8/86) were identified. CONCLUSIONS: We recommend regular monitoring for ophthalmological manifestations of JS beginning soon after birth or diagnosis. We demonstrate delayed visual development and note that the amblyogenic time frame may last significantly longer in JS than is typical. In general, patients with coloboma were less likely to display retinal degeneration, and those with retinal degeneration did not have coloboma. Severe retinal degeneration that is early and aggressive is seen in disease caused by specific genes, such as CEP290- and AHI1-associated JS. Retinal degeneration in INPP5E-, MKS1-, and NPHP1-associated JS was generally milder. Finally, ptosis surgery can be helpful in a subset of patients with JS; decisions as to timing and benefit/risk ratio need to be made on an individual basis according to expert consultation.

Amyloid clearance defect in ApoE4 astrocytes is reversed by epigenetic correction of endosomal pH.

Endosomes have emerged as a central hub and pathogenic driver of Alzheimer's disease (AD). The earliest brain cytopathology in neurodegeneration, occurring decades before amyloid plaques and cognitive decline, is an expansion in the size and number of endosomal compartments. The strongest genetic risk factor for sporadic AD is the ε4 allele of Apolipoprotein E (ApoE4). Previous studies have shown that ApoE4 potentiates presymptomatic endosomal dysfunction and defective endocytic clearance of amyloid beta (Aß), although how these two pathways are linked at a cellular and mechanistic level has been unclear. Here, we show that aberrant endosomal acidification in ApoE4 astrocytes traps the low-density lipoprotein receptor-related protein (LRP1) within intracellular compartments, leading to loss of surface expression and Aß clearance. Pathological endosome acidification is caused by ε4 risk allele-selective down-regulation of the Na+/H+ exchanger isoform NHE6, which functions as a critical leak pathway for endosomal protons. In vivo, the NHE6 knockout (NHE6KO) mouse model showed elevated Aß in the brain, consistent with a causal effect. Increased nuclear translocation of histone deacetylase 4 (HDAC4) in ApoE4 astrocytes, compared with the nonpathogenic ApoE3 allele, suggested a mechanistic basis for transcriptional down-regulation of NHE6. HDAC inhibitors that restored NHE6 expression normalized ApoE4-specific defects in endosomal pH, LRP1 trafficking, and amyloid clearance. Thus, NHE6 is a downstream effector of ApoE4 and emerges as a promising therapeutic target in AD. These observations have prognostic implications for patients who have Christianson syndrome with loss of function mutations in NHE6 and exhibit prominent glial pathology and progressive hallmarks of neurodegeneration.

EXPANDED PHENOTYPE OF TMEM67 GENE MUTATION (CASE REPORT).

Human ciliopathies are a class of multi-organ genetic disorders caused by defects of proteins expressed at the primary cilium, an organelle present on the cell surface of almost all cell types. Thus far, dozens of causative genes for ciliopathies have been identified and many of them are known to cause allelic disease. Of particular interest is the TMEM67 gene, encoding the transmembrane protein meckelin. The involvement of the mutant TMEM67 gene is known to be associated with a broad range of clinical presentations, namely Joubert syndrome 6 (JBTS6), nephronophthisis 11 (NPHP11), Bardet-Biedel syndrome (BBS), COACH syndrome, and lethal Meckel syndrome type 3 (MKS3). Here we present a case of a 3-year-old boy with compound heterozygous missense mutations in the TMEM67 gene manifesting features of both JBTS and NPHP syndromes, with neonatal onset of end-stage renal disease (ESRD) and associated microcephaly. Such a phenotype has not been reported to date, thus highlighting the diversity of ciliopathies and expanding the phenotype of the TMEM67 gene.

An exome sequencing study of Moebius syndrome including atypical cases reveals an individual with CFEOM3A and a TUBB3 mutation.

Moebius syndrome is characterized by congenital unilateral or bilateral facial and abducens nerve palsies (sixth and seventh cranial nerves) causing facial weakness, feeding difficulties, and restricted ocular movements. Abnormalities of the chest wall such as Poland anomaly and variable limb defects are frequently associated with this syndrome. Most cases are isolated; however, rare families with autosomal dominant transmission with incomplete penetrance and variable expressivity have been described. The genetic basis of this condition remains unknown. In a cohort study of nine individuals suspected to have Moebius syndrome (six typical, three atypical), we performed whole-exome sequencing to try to identify a commonly mutated gene. Although no such gene was identified and we did not find mutations in PLXND1 and REV3L, we found a de novo heterozygous mutation, p.E410K, in the gene encoding tubulin beta 3 class III (TUBB3), in an individual with atypical Moebius syndrome. This individual was diagnosed with near-complete ophthalmoplegia, agenesis of the corpus callosum, and absence of the septum pellucidum. No substantial limb abnormalities were noted. Mutations in TUBB3 have been associated with complex cortical dysplasia and other brain malformations and congenital fibrosis of extraocular muscles type 3A (CFEOM3A). Our report highlights the overlap of genetic etiology and clinical differences between CFEOM and Moebius syndrome and describes our approach to identifying candidate genes for typical and atypical Moebius syndrome.

A Christianson syndrome-linked deletion mutation (∆(287)ES(288)) in SLC9A6 disrupts recycling endosomal function and elicits neurodegeneration and cell death.

BACKGROUND: Christianson Syndrome, a recently identified X-linked neurodevelopmental disorder, is caused by mutations in the human gene SLC9A6 encoding the recycling endosomal alkali cation/proton exchanger NHE6. The patients have pronounced limitations in cognitive ability, motor skills and adaptive behaviour. However, the mechanistic basis for this disorder is poorly understood as few of the more than 20 mutations identified thus far have been studied in detail. METHODS: Here, we examined the molecular and cellular consequences of a 6 base-pair deletion of amino acids Glu(287) and Ser(288) (∆ES) in the predicted seventh transmembrane helix of human NHE6 expressed in established cell lines (CHO/AP-1, HeLa and neuroblastoma SH-SY5Y) and primary cultures of mouse hippocampal neurons by measuring levels of protein expression, stability, membrane trafficking, endosomal function and cell viability. RESULTS: In the cell lines, immunoblot analyses showed that the nascent mutant protein was properly synthesized and assembled as a homodimer, but its oligosaccharide maturation and half-life were markedly reduced compared to wild-type (WT) and correlated with enhanced ubiquitination leading to both proteasomal and lysosomal degradation. Despite this instability, a measurable fraction of the transporter was correctly sorted to the plasma membrane. However, the rates of clathrin-mediated endocytosis of the ∆ES mutant as well as uptake of companion vesicular cargo, such as the ligand-bound transferrin receptor, were significantly reduced and correlated with excessive endosomal acidification. Notably, ectopic expression of ∆ES but not WT induced apoptosis when examined in AP-1 cells. Similarly, in transfected primary cultures of mouse hippocampal neurons, membrane trafficking of the ∆ES mutant was impaired and elicited marked reductions in total dendritic length, area and arborization, and triggered apoptotic cell death. CONCLUSIONS: These results suggest that loss-of-function mutations in NHE6 disrupt recycling endosomal function and trafficking of cargo which ultimately leads to neuronal degeneration and cell death in Christianson Syndrome.

Recessive Mutation in a Nuclear-Encoded Mitochondrial tRNA Synthetase Associated With Infantile Cataract, Congenital Neurotrophic Keratitis, and Orbital Myopathy.

PURPOSE: To report the ocular findings of a rare case of mutation in the nuclear-encoded mitochondrial aminoacyl-tRNA synthetase IARS2. METHODS: A 33-year-old woman known for infantile cataracts, growth hormone deficiency, sensory neuropathy, sensorineural hearing loss, and skeletal dysplasia was referred to us for multiple failed corneal grafts and severe eye dryness. RESULTS: The patient was found to have neurotrophic keratitis and corneal opacification. CONCLUSIONS: Patients with this very rare mutation present with a myriad of ocular findings, including infantile cataract, neurotrophic keratitis, corneal opacification, and orbital myopathy.

[Alternating hemiplegia of childhood: ATP1A3 gene analysis in 16 patients]. / Hemiplejía alternante de la infancia: estudio del gen ATP1A3 en 16 pacientes.

BACKGROUND AND OBJECTIVE: Alternating hemiplegia in childhood (AHC) is a disease characterized by recurrent episodes of hemiplegia, tonic or dystonic crisis and abnormal ocular movements. Recently, mutations in the ATP1A3 gene have been identified as the causal mechanism of AHC. The objective is to describe a series of 16 patients with clinical and genetic diagnosis of AHC. PATIENTS AND METHOD: It is a descriptive, retrospective, multicenter study of 16 patients with clinical diagnosis of AHC in whom mutations in ATP1A3 were identified. RESULTS: Six heterozygous, de novo mutations were found in the ATP1A3 gene. The most frequent mutation was G2401A in 8 patients (50%) followed by G2443A in 3 patients (18.75%), G2893A in 2 patients (12.50%) and C2781G, G2893C and C2411T in one patient, respectively (6.25% each). CONCLUSIONS: In the studied population with AHC, de novo mutations were detected in 100% of patients. The most frequent mutations were D801N y la E815K, as reported in other series.

Ataxia, intellectual disability, and ocular apraxia with cerebellar cysts: a new disease?

Cerebellar cysts are rare findings in pediatric neuroimaging and rather characteristic for dystroglycanopathies and GPR56-related encephalopathy. We aim to report on seven children with cerebellar cysts showing absence of weakness and ruling out mutations within eight dystroglycanopathy genes and GPR56. Data about neurological and ophthalmological features, outcome, and creatine kinase values were collected from clinical histories and follow-up examinations. All MR images were qualitatively evaluated for infra- and supratentorial abnormalities. A SNP 6.0-Array was performed in three children. The POMT1, POMT2, POMGnT1, FKRP, FKTN, LARGE, ISPD, B3GALNT2, and GPR56 genes were screened in all patients by Sanger sequencing. Seven children from five families were studied. Ataxia, intellectual disability, and language impairment were found in all patients, ocular motor apraxia in five, and severe myopia in three. None of the patients had weakness, only three a minimally increased creatine kinase value. Qualitative neuroimaging evaluation showed cerebellar cysts and dysplasia in the cerebellar hemispheres and vermis in all children. Additional findings were an enlarged fourth ventricle in all children, vermian hypoplasia and brain stem morphological abnormalities in five. The SNP array showed no pathogenetic imbalances in all children evaluated. In all patients, no mutations were found in POMT1, POMT2, POMGnT1, FKRP, FKTN, LARGE, ISPD, B3GALNT2, and GPR56. The peculiar combination of the same clinical and neuroimaging findings in our patients highly suggests that this phenotype may represent a novel entity, possibly falling within the spectrum of dystroglycanopathies.

Diffusion tensor imaging and fiber tractography in brain malformations.

Diffusion tensor imaging (DTI) is an advanced MR technique that provides qualitative and quantitative information about the micro-architecture of white matter. DTI and its post-processing tool fiber tractography (FT) have been increasingly used in the last decade to investigate the microstructural neuroarchitecture of brain malformations. This article aims to review the use of DTI and FT in the evaluation of a variety of common, well-described brain malformations, in particular by pointing out the additional information that DTI and FT renders compared with conventional MR sequences. In addition, the relevant existing literature is summarized.

Partial chromosome 7 duplication with a phenotype mimicking the HOXA1 spectrum disorder.

PURPOSE: To evaluate possible monogenic and chromosomal anomalies in a patient with bilateral Duane retraction syndrome and hearing impairment resulting in a phenotype resembling the HOXA1 spectrum disorder. METHODS: Sequencing HOXA1 and performing high resolution array comparative genomic hybridization (arrayCGH). RESULTS: The proband had bilateral Duane retraction syndrome (DRS) with severe hearing loss bilaterally and an absent right vertebral artery, mimicking the major features of the Bosley-Salih-Alorainy variant of the HOXA1 spectrum. However, he also had developmental delay, mild mental retardation, and seizures. His parents were not related, but his father had milder sensorineural hearing loss bilaterally, and two paternal uncles and a paternal cousin had seizures. Neuroimaging revealed moderate maldevelopment of inner ear bony anatomy bilaterally. HOXA1 sequencing was normal, but arrayCGH revealed a small partial duplication of chromosome 7 encompassing only the PTPRN2 gene (protein tyrosine phosphatase, receptor type, N polypeptide 2) that was not present in his parents, an unaffected brother, or 53 normal ethnically-matched individuals. CONCLUSIONS: PTPRN2 is not yet linked to a genetic syndrome, although its expression has been identified in the adult human brain, in certain tumors, and in association with type 1 diabetes mellitus. The phenotype of this patient is strikingly similar to, but not identical to, that of the HOXA1 spectrum disorder. The findings in this patient raise the possibility that PTPRN2 may be active during early development of the human brainstem and that its overexpression may cause bilateral DRS with hearing loss as occurs in patients with homozygous HOXA1 mutations.

Congenital myopathy with focal loss of cross-striations revisited.

In 1977 Wijngaarden et al. reported a Dutch family with a congenital myopathy characterized by external ophthalmoplegia and a remarkable histological feature, focal loss of cross-striations. A small number of other families with similar clinical and pathological features led to the consideration of this congenital myopathy as a distinct entity. Here we present more than 30years of follow-up from the Dutch family and report recently identified compound heterozygous mutations in the skeletal muscle ryanodine receptor (RYR1) gene, c.10627-2A>G and p.Arg3539His (c.10616G>A). Focal loss of cross-striations on muscle biopsy is another histopathological feature that should raise the possibility of RYR1 involvement.

[A family of congenital fibrosis of extraocular muscles associated with naso-sinusitis].

OBJECTIVE: To clinically characterize a collected family of congenital fibrosis of extraocular muscles associated with naso-sinusitis, then determine the genetic location of the disease gene by linkage analysis to approach the etiopathogenesis of CFEOM on gene. METHODS: A CFEOM family (fifteen cases suffering from congenital general fibrosis syndrome in four generations of 41 members) was collected. All the suffers were correlated with clinical ophthalmic and thin-sectioned magnetic resonance imaging across the orbit and the brain-stem level to determine its clinical classification and genetic characteristics. The family was tested for linkage analysis to two known autosomal dominant CFEOM loci on chromosome 12p11. 2-q12 (FEOM1 ) and 16q24 (FEOM3). RESULTS: All the suffers had congenital unilateral or bilateral blepharoptosis, head tilt, chin lift, primary gaze fixed in a hypo-and exotropic position, forced duction testing positive. But vertical and horizontal positions of the eye and restriction of eye movement were different among affected individuals. Furthermore, MRI examinations showed that all the incidence of those families associated with naso-sinusitis and hypertrophic inferior turbinate, and the juveniles with hypertrophic adenoid. Pedigree shows that the family were in line with the characteristics of autosomal dominant inheritance. According to the genetic characteristics and clinical manifestations, the genetic family should be referred as CFEOM3. The lod scores for D12S331, D12S59 and D12S1668 were between 1 and 3, and the maximum lod score was 2. 19 for D12S1048, but the lod scores for D16S520, D16S498 and D16S2621 were both < 1.0. CONCLUSION: This family is best classified as CFEOM3 and linkage with D12S331, D12S59 and D12S1668.

Genetic association analysis of ERBB4 polymorphisms with the risk of schizophrenia and SPEM abnormality in a Korean population.

The human receptor tyrosine-protein kinase erbB-4 (ERBB4) gene mediates neuregulin 1 (NRG1) signaling, and is involved in neuronal migration and differentiation. Despite the potential significance of ERBB4 in the development of schizophrenia, relatively few genetic studies for the association of ERBB4 with schizophrenia were performed in the populations including Ashkenazi Jews, Americans including Caucasians and African Americans, and Han Chinese. In this study, differences in ERBB4 variations were investigated to determine association with schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. Seven polymorphisms in ERBB4 gene were genotyped in 435 schizophrenia cases and 390 unrelated healthy controls. In order to investigate the relationship between ERBB4 and the risk of schizophrenia and SPEM abnormality, differences in SNP and haplotype distribution were analyzed using logistic and multiple regression analyses. However, we failed to replicate the associations reported by previous studies in other populations. Although statistically not significant, the tendency towards associations between ERBB4 polymorphisms and the risk of schizophrenia and SPEM abnormality in this study from a Korean population would be helpful for further genetic etiology studies in schizophrenia.

Different molecular expression in thymoma with ocular or generalized myasthenia gravis.

BACKGROUND: Increasing evidence supports a link between expressions of CD4, CD25, Foxp3, and CXCL13 in thymic hyperplasia with myasthenia gravis (MG) patients. Herein, we investigated the expressions of these molecules in thymoma patients with ocular MG (OMG) or generalized MG (GMG). METHODS: A total of 58 thymoma patients with MG (23 GMG and 35 OMG) and 73 thymoma patients without MG were analyzed using immunohistochemistry for CD4, CD25, Foxp3 and CXCL13. RESULTS: OMG was more frequent than GMG in late-onset thymoma males (P=0.037), but no difference was observed in females (P=0.128). There was no significant difference of Foxp3 expression among all types of thymoma from patients with OMG and Non-MG. Compared to patients with OMG, a decreased Foxp3 expression was seen in types AB, B1 and B2 thymoma with GMG, with the decrease in the former two types reaching significance (P=0.001, 0.043, respectively). However, a significantly increased expression of CXCL13 was observed in types B1 and B2 thymoma patients with GMG (P=0.027, 0.048, respectively, compared to those with OMG). Furthermore, the CXCL13 expression in type AB thymoma patients with GMG was higher than those with Non-MG (P=0.003).There were no differences among expressions of CD4, CD25, Foxp3, and CXCL13 in type A and B3 thymoma patients, regardless of with OMG, GMG or Non-MG. CONCLUSION: Differential expressions of Foxp3 and CXCL13 in various types of thymoma patients with OMG or GMG might suggest the differential immunological processes underlying the two subtype of MG.