Patterns and severity of neuromuscular transmission failure in seronegative myasthenia gravis

OBJECTIVES

To compare the clinical and electrophysiological features of myasthenia gravis (MG) patients with (seropositive) or without (seronegative) antibodies to acetylcholine receptor. To investigate whether antibodies to muscle specific kinase (MuSK) and ryanodine receptor (RyR) are associated with particular features.

METHODS

Clinical profiles and single fibre electromyography (SFEMG) in the extensor digitorum communis (EDC) were reviewed in consecutive 57 seropositive and 13 seronegative patients. Antibodies to MuSK and RyR were measured by immunoassays.

RESULTS

Of the 13 seronegative patients, four (31%) were positive for MuSK antibodies and seven (54%) were positive for RyR antibodies, including all four MuSK positive patients. Clinical features were similar at presentation for seropositive and seronegative patients, but MuSK positive patients frequently developed myasthenic crises. Despite the similar clinical severities at the time of examination, the proportion with positive jitter (93% of seropositive patients, 50% of MuSK positive patients, and 44% of MuSK negative patients) and the extent of jitter (mean consecutive difference: 76 micros in seropositive patients, 36 micros in MuSK positive patients, and 30 micros in MuSK negative patients) were less in seronegative MG patients compared with seropositive MG patients.

CONCLUSIONS

Seronegative MG is heterogeneous with respect to the presence of antibodies to MuSK. Impairment of neuromuscular synaptic transmission in EDC is less marked in seronegative than seropositive MG despite the similar clinical severity. This discrepancy may partly reflect the distribution of affected muscles in seronegative patients, but it is possible that other factors, such as impaired excitation-contraction coupling resulting from RyR antibodies, contribute to the clinical phenotype.

Association between neuroleptic drug-induced extrapyramidal symptoms and dopamine D2-receptor polymorphisms in Japanese schizophrenic patients

The aim of the present study is to examine the relationship between dopamine D2-receptor gene (DRD2) polymorphisms (Taq1A, Taq1B, -141C Ins/Del) and the risk of extrapyramidal adverse effects (EPS), assessed according to the Drug-Induced Extra-Pyramidal Symptoms Scale (DIEPSS), or the maintenance dose of antipsychotics in schizophrenic patients. The DIEPSS score was significantly higher in patients bearing the -141C Del allele than in those without it. Taq1A and Taq1B restriction fragment length polymorphisms (RFLPs) did not significantly affect the DIEPSS score. On the other hand, maintenance doses of neuroleptics and antiparkinsonian drugs were significantly higher in patients with the B1 allele of Taq1B RFLP than in those without it, while the Taq1A RFLP and -141C Ins/Del polymorphisms were not significantly related to the maintenance doses. In conclusion, the risk of EPS may be increased in patients with the -141C Del allele of the DRD2 gene. In these patients, antipsychotics should be administered with caution.

Anti-ryanodine receptor antibodies and FK506 in myasthenia gravis

Anti-ryanodine receptor (RyR) antibodies were measured in sera from 33 myasthenia gravis (MG) patients using three peptides from the human RyR1 sequence, two C-terminal peptides included in the functional calcium release channel, and an N-terminal peptide implicated in ion-conduction. Antibodies were more frequently positive against the two C-terminal peptides, particularly in thymoma-associated MG. In a preliminary open trial with FK506, immunosuppressant and enhancer of RyR-related sarcoplasmic calcium release, the authors observed the sustained benefits in anti-RyR-positive MG patients.

Primary Sjogren's syndrome presenting with generalized autonomic failure

A 64 year-old woman developed Raynaud's phenomenon and dry eyes/mouth. Laboratory examination revealed positive Schirmer's test, rheumatoid factor and anti-nuclear antibody, and lymphocytic sialoadenitis on salivary gland biopsy. These features strongly suggested the diagnosis of primary Sjogren's syndrome. Three years later, she gradually developed generalized autonomic failure without apparent sensory neuropathy on nerve conduction study. She had systolic pressure fall of 51 mmHg on head-up tilt test, cardiovascular supersensitivity to diluted norepinephrine infusion, cardiac denervation in [123I]-MIBG scintigraphy, impaired R-R variability, decreased sweating and prolonged colonic transit time. Autoimmune autonomic ganglionopathy was mostly responsible for her autonomic failure.

Cell Simulation for Circadian Rhythm Based on Michaelis-MentenModel

We report here the development of a cell biological simulation systembased on ordinary differential equations and the results on the simulationof the heat pulses' effects on the circadian rhythm in Drosophila.The simulator implements intra-cellular processes: transcription,translation, transport, modification (association, disassociation),degradation. It simulates the temporal behavior of concentrations ofproteins and mRNA involved in various biological phenomena. Moreover, thesystem is able to determine the exact type of reaction for a givenregulatory pathway. In order to prove the usefulness of the simulator weconstruct a model of the circadian rhythm in Drosophilaand wesimulate the effect of the heat pulses applied in early afternoon on thecircadian clock proteins PER and TIM. Our simulation results show therobustness of the genetic network as well as the important role playedby dClk mRNA in the mechanism of phase-shift responses.

Differential expression of endophilin 1 and 2 dimers at central nervous system synapses

Endophilin 1 is proposed to participate in synaptic vesicle biogenesis through SH3 domain-mediated interactions with the polyphosphoinositide phosphatase synaptojanin and the GTPase dynamin. Endophilin family members have also been identified as binding partners for a number of diverse cellular proteins. We define here the endophilin 1-binding site within synaptojanin 1 and show that this sequence independently and selectively purifies from brain extracts endophilin 1 and a closely related protein, endophilin 2. Endophilin 2, like endophilin 1, is highly expressed in brain, concentrated in nerve terminals, and found in complexes with synaptojanin and dynamin. Although a fraction of endophilins 1 and 2 coexist in the same complex, the distribution of these endophilin isoforms among central synapses only partially overlaps. Endophilins 1 and 2 are found predominantly as stable dimers through a predicted coiled-coil domain in their conserved NH2-terminal moiety. Dimerization may allow endophilins to link a number of different cellular targets to the endocytic machinery.

Identification and characterization of a synaptojanin 2 splice isoform predominantly expressed in nerve terminals

We have previously identified synaptojanin 1, a phosphoinositide phosphatase predominantly expressed in the nervous system, and synaptojanin 2, a broadly expressed isoform. Synaptojanin 1 is concentrated in nerve terminals, where it has been implicated in synaptic vesicle recycling and actin function. Synaptojanin 2A is targeted to mitochondria via a PDZ domain-mediated interaction. We have now characterized an alternatively spliced form of synaptojanin 2 that shares several properties with synaptojanin 1. This isoform, synaptojanin 2B, undergoes further alternative splicing to generate synaptojanin 2B1 and 2B2. Both amphiphysin and endophilin, two partners synaptojanin 1, bind synaptojanin 2B2, whereas only amphiphysin binds synaptojanin 2B1. Sequence similar to the endophilin-binding site in synaptojanin 1 is present only in synaptojanin 2B2, and this sequence was capable of affinity purifying endophilin from rat brain. The Sac1 domain of synaptojanin 2 exhibited phosphoinositide phosphatase activity very similar to that of the Sac1 domain of synaptojanin 1. Site-directed mutagenesis further illustrated its functional similarity to the catalytic domain of Sac1 proteins. Antibodies raised against the synaptojanin 2B-specific carboxyl-terminal region identified a 160-kDa protein in brain and testis. Immunofluorescence showed that synaptojanin 2B is localized at nerve terminals in brain and at the spermatid manchette in testis. Active Rac1 GTPase affects the intracellular localization of synaptojanin 2, but not of synaptojanin 1. These results suggest that synaptojanin 2B has a partially overlapping function with synaptojanin 1 in nerve terminals, with additional roles in neurons and other cells including spermatids.

Insulin mimetic effect of a tungstate cluster. Effect of oral administration of homo-polyoxotungstates and vanadium-substituted polyoxotungstates on blood glucose level of STZ mice

Aqueous vanadate and aqueous tungstate have been known to mimic all or most of the actions of insulin in intact cell systems with respect to normalization of the blood glucose level. By carrying out oral administration in vivo experiments on the blood glucose level of streptozotocin (STZ)-induced diabetes (STZ mice), the insulin-mimetic (IM) effects of metal-oxide clusters of all-inorganic composition were examined using many types of polyoxometalates (POM) with and without vanadium substitution. Several homo-POM and vanadium-substituted POM showed hypoglycemic effects. The observed hypoglycemic effects indicated that POM with the Dawson structure [[alpha-P(2)W(18)O(62)](6-) (W-2), [alpha-P(2)W(17)V(V)O(62)](7-) (V-19) and [alpha-1,2,3-P(2)W(15)V(V)(3)O(62)](9-) (V-04)] are more effective than those with the Keggin structure [[alpha-PW(12)O(40)](3-) (W-1), [alpha-PW(11)V(V)O(40)](4-) (V-01), [alpha-1,2-PW(10)V(V)(2)O(40)](5-) (V-02), [alpha-1,2,3-PW(9)V(V)(3)O(40)](6-) (V-03) and [alpha-1,4,9-PW(9)V(V)(3)O(40)](6-) (V-13)]. The vanadate cluster [V(10)O(28)](6-) (V-15) also showed a hypoglycemic effect. (31)P and (51)V NMR measurements showed that the Dawson POM (W-2, V-04 and V-19) are stable in aqueous solution under the conditions used. The effect of all POM on the body weight of STZ mice was also examined. The decrease in body weight after administration of W-2 was much less than for V-19, V-04 and V-15. This suggests that not only monomeric tungstate and vanadate, but also the structure factors of tungstate and vanadate clusters, can play a significant role in their biological action.

Facial nerve anatomy in eyelids and periorbit

PURPOSE

To clarify anatomically the facial nerve branches in the eyelids and periorbit.

METHODS

The facial nerve branches of the left periorbits from 31 Japanese cadavers were dissected under a surgical microscope.

RESULTS

The temporal, zygomatic, and deep buccal branches assembled posterior to the orbicularis oculi from its temporal or inferior side, and formed a dense plexus. The superficial buccal branches coursed, unlike the others, around the inferior nasal margin of the orbicularis oculi with some variations. The branches always passed across the "triangular window" that was outlined by the orbicularis oculi, the zygomaticus minor, and the levator labii superioris alaeque nasi. Then the branches crossed over the medial palpebral ligament, reaching both the procerus and corrugator supercilii in 94% of the specimens. The branches ramified the lower part of the orbicularis oculi in 65% and the upper part in 42% of the specimens.

CONCLUSIONS

The superficial buccal branches are the main supplier to the muscles in the nasal periorbit. This anatomical finding may be important information for accurate procedures in facial nerve surgery.

[Bilateral progressive supra-fixing eyes with congenital misinsertion of inferior rectus muscles--a case report]

BACKGROUND

We report on a rare case with misinsertion of the inferior rectus muscles, that showed bilateral progressive supra-fixing eyes.

CASE

A 68-year-old woman showed bilateral progressive supra-fixing eyes with low vision that was caused by microcorneas and retionochoroidal atrophy. Passive infraduction was restricted bilaterally, but the right inferior rectus muscle was innervated normally. Magnytic resonance imaging(MRI) demonstrated nasal misposition of bilateral inferior rectus muscles. The patient's eye position was improved after combined transposition of the inferior rectus muscles that were misinserted nasally to the inferior poles of the eyes and superior rectus muscle recession, without any complications.

CONCLUSION

A dysfunction of bilateral depressor muscles and low vision may cause this condition. Accurate diagnosis with MRI and correction of the affected muscles to the normal anatomical position produces satisfying results in such cases.

Outcome of surgery for congenital fibrosis of the inferior rectus muscle

PURPOSE

To report clinical findings and surgical outcome in a large series of patients with fibrosis of the inferior rectus muscle.

MATERIALS AND METHODS

Subject Cases: A total of 17 cases were diagnosed with unilateral fibrosis of the inferior rectus muscle during the past 27 years at our institution. They were aged from 5 months to 17 years, with 15 cases under 10 years of age. No differences were present regarding the laterality or gender.

FINDINGS

All the cases showed hypotropia with restricted eye elevation. Forced duction test showed resistance to upward eye movement. A horizontal deviation in primary eye position was also present in 10 cases (59%). The affected eye was amblyopic in the majority of cases. Binocular vision was absent in 15 of the 17 cases.

RESULTS

Surgical Outcome: All the cases received either recession or free tenotomy of the inferior rectus muscle. Resection of the ipsilateral superior rectus muscle was additionally performed to correct residual hypotropia. Fibrosis of the inferior rectus was present as intraoperative finding in all the 17 cases. Hypotropia disappeared in 10 cases and decreased in 7 cases. Restoration of satisfactory binocular alignment was obtained in all the 17 cases.

CONCLUSION

Recession of the inferior rectus muscle was effective treatment for fibrosis of the inferior rectus. Additional resection of the ipsilateral superior rectus muscle was useful to correct residual hypotropia. Free tenotomy is not recommended.

Detection of human herpesvirus 6 and JC virus in progressive multifocal leukoencephalopathy complicating follicular lymphoma

Progressive multifocal leukoencephalopathy (PML), a demyelinating infectious disease caused by JC virus (JCV), occurs almost exclusively in immunocompromised patients usually with malignant diseases. We report here a Japanese female with follicular lymphoma who subsequently developed PML. In addition to JCV, human herpesvirus 6 (HHV-6) was detected in the affected brain lesions of the patient by polymerase chain reaction and by in situ hybridization. HHV-6, recognized as a neurotropic virus, is known to be reactivated during immunosuppression and can cause fatal complications such as encephalitis/encephalopathy. It is likely that impaired immunity associated with lymphoma and the additional immunosuppression following cytopenia-inducing chemotherapies predisposed the patient to reactivated HHV-6 infection. Although it remains to be clarified whether HHV-6 plays an important role as a co-agent with JCV in causing demyelination of the brain, our observation alerts physicians to the possible association of HHV-6 with the pathogenesis of PML.

[A clear cell type meningioma in the upper eyelid ascertained by immunohistochemical examination]

BACKGROUND

We encountered a rare case of clear cell meningioma in the upper eyelid.

CASE

A 66-year-old man presented with a slow by progressive, well-defined, soft globelar tumor in the left upper eyelid. The tumor showed homogeneous isodensity and was contrasty in a computed tomograph. Histologically, oval-shaped cells with clear cytoplasm had both streamed and whorl configurations, but showed neither psammomas nor calcification. Immunohistochemically, vimentin, epithelial membrane antigen, and protein S-100 were expressed by the tumor cells.

CONCLUSIONS

Eyelid meningioma may originate from embryonal remains of the arachnoid in the sheath around the trigeminal nerve, and may vary histologically. Immunohistochemical examination helps to define cases of uncommon subtypes of meningioma.

The "botryoid sign": a characteristic feature of rhabdomyosarcomas in the head and neck

We investigated nine patients with rhabdomyosarcoma in the head and neck (6-53 years of age), using CT and MRI. The tumours originated in the paranasal sinuses (3), cheek (2), soft palate (1), orbit (1), sternocostoclavicular muscle (1) and parapharyngeal space (1). The histological subtype was embryonal in five, alveolar in three and pleomorphic in one case. The tumours enhanced markedly and heterogeneous on CT and MRI. The masses were isointense or gave slightly higher signal than surrounding muscles on T1- and heterogeneously high signal on T2-weighted images. In four tumours, multiple ring enhancement resembling bunches of grapes. This appears to be characteristic of rhabdomyosarcoma and probably reflects a component of botryoid-type rhabdomyosarcoma in which mucoid-rich stroma is covered with a thin layer of tumour cells. We have named this imaging feature the "botryoid sign".

Lactate dehydrogenase production and release in a newly established human myeloma cell line

Aggressive multiple myeloma with high serum lactate dehydrogenase (LDH) often has unusual clinical features and is considered to be a distinct clinical entity of multiple myeloma. A myeloma cell line, designated Maska-98, was established from the bone marrow of a patient with aggressive myeloma with extremely high serum LDH that was resistant to conventional chemotherapy. Maska-98 cells had morphological features of immature plasma cells, and immunophenotypic analysis showed that the cells expressed the plasma cell-associated surface antigens including CD38, 49d, and 56, but no T- or B-cell antigens, such as CD2, 3, 4, 8, 19, and 20. Maska-98 cells contained cytoplasmic immunoglobulin (IgG lambda). By utilizing this cell line we demonstrated that the myeloma cells produce and release a large amount of LDH, since (i) abundant LDH was found in the culture supernatant of Maska-98, (ii) immunocytochemical analysis showed that cytoplasm of the cells was strongly stained with anti-LDH monoclonal antibody, and (iii) Maska-98 cells expressed a greater amount of LDH mRNA than the T-cell line TALL-1, as shown by reverse transcription-polymerase chain reaction. As far as we know, there is no report of a myeloma cell line producing excess LDH. Therefore, Maska-98 would provide a novel source for further studies of the pathogenesis of aggressive multiple myeloma with high serum LDH.

Syringomyelia associated with adhesive spinal arachnoiditis: MRI

We reviewed the MRI of seven patients with syringomyelia associated with surgically proven adhesive spinal arachnoiditis to describe clinical and MRI findings in this condition. Using 0.5, 1.0 or 1.5 tesla units, we obtained sagittal T1- and T2-weighted spin-echo and axial T1-weighted images. Additional sagittal T2-weighted images were obtained without using motion-artefact suppression. Contrast medium was given intravenously to five patients. The syrinx cavities were thoracic in five cases, cervicothoracic in one, and extended from C4 to L1 in one. No Chiari malformation or craniovertebral junction anomaly was demonstrated. Meningeal thickening was seen on T2-weighted sagittal images only in one case. Cord deformity due to adhesion or displacement due to an associated arachnoid cyst was seen in all cases best demonstrated on axial images. Focal blurring of the syrinx wall on axial images was seen in six patients. Flow voids were seen in the syrinx fluid in all cases on T2-weighted images obtained without motion-artefact suppression. No abnormal contrast enhancement was demonstrated.

[A case of orbital MALT lymphoma in which 67Ga scintigraphy was useful for evaluating the radiation therapy response]

A 67-year-old man was hospitalized at our institution complaining with epiphora and exophthalmos on the left side. Magnetic resonance imaging (MRI) showed an ill demarcated retrobulbar mass in the left orbit. 67Ga scintigraphy revealed avid uptake in the left orbital region. The patient was treated with radiation therapy. One month after the radiation therapy, the size of the mass decreased remarkably on MRI. 67Ga planar imaging after treatment showed no uptake, but 67Ga SPECT showed slightly increased uptake in the left orbital region. One year after the radiation therapy, MRI showed residual mass in the left orbital region. Both 67Ga planar imaging and SPECT showed no uptake in the left orbital region. 1.8 years after the radiation therapy, MRI showed the residual mass with no interval change in size. Both 67Ga planar imaging and SPECT showed no uptake in the left orbital region. The patient remains well with no evidence of local recurrence. 67Ga scintigraphy is useful in assessing the response to radiation therapy of MALT lymphoma in this case.

Three-Quark Potential in SU(3) Lattice QCD

The static three-quark ( 3Q) potential is studied in SU(3) lattice QCD with 12(3)x24 and beta = 5.7 at the quenched level. From the 3Q Wilson loop, 3Q ground-state potential V(3Q) is extracted using the smearing technique for ground-state enhancement. With accuracy better than a few percent, V(3Q) is well described by a sum of a constant, the two-body Coulomb term, and the three-body linear confinement term sigma(3Q)L(min), with L(min) the minimal value of total length of color flux tubes linking the three quarks. Comparing with the Q-&Qmacr; potential, we find a universal feature of the string tension, sigma(3Q) approximately sigma(Q&Qmacr;), and the OGE result for Coulomb coefficients, A(3Q) approximately 1 / 2A(Q&Qmacr;).

Functional characterization of a mammalian Sac1 and mutants exhibiting substrate-specific defects in phosphoinositide phosphatase activity

The Saccharomyces cerevisiae SAC1 gene was identified via independent analyses of mutations that modulate yeast actin function and alleviate the essential requirement for phosphatidylinositol transfer protein (Sec14p) activity in Golgi secretory function. The SAC1 gene product (Sac1p) is an integral membrane protein of the endoplasmic reticulum and the Golgi complex. Sac1p shares primary sequence homology with a subfamily of cytosolic/peripheral membrane phosphoinositide phosphatases, the synaptojanins, and these Sac1 domains define novel phosphoinositide phosphatase modules. We now report the characterization of a rat counterpart of Sac1p. Rat Sac1 is a ubiquitously expressed 65-kDa integral membrane protein of the endoplasmic reticulum that is found at particularly high levels in cerebellar Purkinje cells. Like Sac1p, rat Sac1 exhibits intrinsic phosphoinositide phosphatase activity directed toward phosphatidylinositol 3-phosphate, phosphatidylinositol 4-phosphate, and phosphatidylinositol 3,5-bisphosphate substrates, and we identify mutant rat sac1 alleles that evoke substrate-specific defects in this enzymatic activity. Finally, rat Sac1 expression in Deltasac1 yeast strains complements a wide phenotypes associated with Sac1p insufficiency. Biochemical and in vivo data indicate that rat Sac1 phosphatidylinositol-4-phosphate phosphatase activity, but not its phosphatidylinositol-3-phosphate or phosphatidylinositol-3, 5-bisphosphate phosphatase activities, is essential for the heterologous complementation of Sac1p defects in vivo. Thus, yeast Sac1p and rat Sac1 are integral membrane lipid phosphatases that play evolutionary conserved roles in eukaryotic cell physiology.

Specific expression of glucose-6-phosphate dehydrogenase (G6PDH) gene by salt stress in wheat (Triticum aestivum L.)

We isolated three kinds of full-length cDNA clones for glucose-6-phosphate dehydrogenase (G6PDH) from wheat. They showed over 80% sequence homology with potato and alfalfa at the amino acid level, suggesting that the genes are highly conserved in angiosperms. The lack of a plastidic signal sequence, as well as a higher transcript accumulation level in roots than leaves, suggested that the wheat cDNA sequences encode the cytosolic isoform of the enzyme. Genomic Southern analysis revealed that the isoform is encoded by a few copies of the gene in the wheat genome. Southern analysis of nullisomic-tetrasomic lines suggested that at least one gene is located on chromosome 2B. The G6PDH transcript started to accumulate in the roots after 2 h of 0.15 M NaCl treatment, reaching its maximal level after 12 h of exposure. The G6PDH gene did not respond to either mannitol or abscisic acid (ABA) treatment. The NaCl-specific early response of the G6PDH gene is discussed in relation to the putative role of the enzyme in the salt stress response in plants.

Differentiation induction in non-lymphocytic leukemia cells upon treatment with mycophenolate mofetil

Inosine 5'-monophosphate (IMP) dehydrogenase catalyzes the rate-limiting reaction of guanine nucleotide biosynthesis and has been implicated in the reaction of cell growth and differentiation. We investigated the ability of mycophenolate mofetil, a prodrug of mycophenolic acid, to induce differentiation in HL-60 and U937 leukemic cells as well as in fresh leukemia cells from patients with non-lymphocytic leukemia. Treatment with mycophenolate mofetil reduced the intracellular guanosine 5'-triphosphate (GTP) levels and induced morphologic and functional differentiation in HL-60 and U937 cells dose-dependently. HL-60 and U937 cells developed macrophage-like cytoplasm as well as the expression of CD11b and CD14 antigens and the ability to oxidize nitroblue tetrazorium (NBT). These changes became evident when the intracellular GTP levels decreased to approximately 20-30% of the untreated control level and were abrogated by the addition of guanosine. In the fresh leukemic cells, differentiation induction was shown in the cells derived from seven of 13 patients. The fresh leukemia cells responding to mycophenolate mofetil revealed significant higher positivity to CD11b, CD14, and NBT before treatment and significantly reduced intracellular GTP levels after treatment compared to the non-responding cells. These findings suggest that mycophenolate mofetil induces differentiation in HL-60 and U937 cells and some fresh leukemia cells with moderate tendency to maturation, by causing a decrease in the intracellular GTP levels. Mycophenolate mofetil could be a promising differentiation inducer in vivo.

Superselective neurectomy with periorbital primary reconstruction for blepharospasm. Case report

A 66-year old man with blepharospasm and ptosis of the brow was treated with a combined procedure in which the branches of the facial nerve were excised at the margin of the orbicularis, and the periorbital area was reconstructed simultaneously. The condition improved after the treatment with no occurrence of either oral complications or facial anaesthesia.

[Progressive paralysis of divergence in an adult with midbrain angioma]

A 37-year-old woman was admitted to the hospital with the complaint of progressive horizontal diplopia of six years' duration when viewing distant objects. On admission she had a slight left convergent strabismus. Homonymous diplopia was present beyond 50 cm and increased on distance fixation. Both eyes were fully mobile in the horizontal plane with a mild decrease in the velocity of horizontal eye movement to the left, and slight impairment of upward eye movement. The left eye did not fully adduct during convergence. The right pupil was slightly larger than the left. Prism cover test showed 6 delta esophoria at 30 cm and 14 delta esophoria at 5 m. The Hess chart showed a convergent deviation. MRI revealed a small right-side paramedian lesion of the midbrain tegmentum lying ventral to the aqueduct of Sylvius, at the level between the superior colliculi and the intercollicular area. A venous angioma with arteriovenous shunts in the right midbrain was diagnosed by angiography. We suggest that lesions that damage the divergence neurons in the tegmentum of the midbrain and also interrupt the supranuclear fibers having an inhibitory effect on the convergence neurons may produce homonymous diplopia on distant fixation combined with the esotropia.