Overlap of polymicrogyria, hydrocephalus, and Joubert syndrome in a family with novel truncating mutations in ADGRG1/GPR56 and KIAA0556.

Genetic mutations associated with brain malformations can lead to a spectrum of severity and it is often difficult to determine whether there are additional pathogenic variants contributing to the phenotype. Here, we present a family affected by a severe brain malformation including bilateral polymicrogyria, hydrocephalus, patchy white matter signal changes, and cerebellar and pontine hypoplasia with elongated cerebellar peduncles leading to the molar tooth sign. While the malformation is reminiscent of bilateral frontoparietal polymicrogyria (BFPP), the phenotype is more severe than previously reported and also includes features of Joubert syndrome (JBTS). Via exome sequencing, we identified homozygous truncating mutations in both ADGRG1/GPR56 and KIAA0556, which are known to cause BFPP and mild brain-specific JBTS, respectively. This study shows how two independent mutations can interact leading to complex brain malformations.

Treponema denticola Has the Potential to Cause Neurodegeneration in the Midbrain via the Periodontal Route of Infection-Narrative Review.

Alzheimer's disease (AD) is a neurodegenerative disease and the most common example of dementia. The neuropathological features of AD are the abnormal deposition of extracellular amyloid-ß (Aß) and intraneuronal neurofibrillary tangles with hyperphosphorylated tau protein. It is recognized that AD starts in the frontal cerebral cortex, and then it progresses to the entorhinal cortex, the hippocampus, and the rest of the brain. However, some studies on animals suggest that AD could also progress in the reverse order starting from the midbrain and then spreading to the frontal cortex. Spirochetes are neurotrophic: From a peripheral route of infection, they can reach the brain via the midbrain. Their direct and indirect effect via the interaction of their virulence factors and the microglia potentially leads to the host peripheral nerve, the midbrain (especially the locus coeruleus), and cortical damage. On this basis, this review aims to discuss the hypothesis of the ability of Treponema denticola to damage the peripheral axons in the periodontal ligament, to evade the complemental pathway and microglial immune response, to determine the cytoskeletal impairment and therefore causing the axonal transport disruption, an altered mitochondrial migration and the consequent neuronal apoptosis. Further insights about the central neurodegeneration mechanism and Treponema denticola's resistance to the immune response when aggregated in biofilm and its quorum sensing are suggested as a pathogenetic model for the advanced stages of AD.

Wernekink commissure syndrome: a rare midbrain syndrome.

Wernekink commissure syndrome is a rare midbrain syndrome, which selectively destroys the Wernekink commissure involving the decussation of superior cerebellar peduncle in midbrain. This syndrome may display a clinical picture: bilateral cerebellar ataxia, eye movement disorders, and palatal tremor. We present two cases of the Wernekink commissure syndrome with acute onset of bilateral cerebellar dysfunction confirmed by magnetic resonance imaging. One patient presented internuclear ophthalmoplegia, but neither showed palatal tremor. It is notable that the bilateral cerebellar dysfunction may be ascribed to midbrain lesion involving the Wernekink commissure, and it may be the sole manifestation of the midbrain lesion.

Malformations of the midbrain and hindbrain: a retrospective study and review of the literature.

We report the results of a retrospective analysis of radiological and clinical findings in 45 cases of midbrain-hindbrain anomalies and review recent advances in embryology and molecular neurogenetics. Among 45 patients with midbrain-hindbrain malformations, 16 cases of molar tooth malformation, 12 of cerebellar hypoplasia, ten of posterior fossa cyst and cerebellar vermian hypoplasia, three of rhombencephalosynapsis, two of Fukuyama congenital muscular dystrophy and two cases of isolated cerebellar dysplasia were identified. Twenty-six patients presented with motor-mental retardation, which was the most common clinical finding. Eleven patients were born to consanguineous parents. The correct diagnosis of cerebellar malformation is important for determining prognosis, the risk of recurrence and the need for genetic counselling. Integrated classification of malformations based on morphology, embryology and molecular neurogenetics may be useful.

Molar tooth sign in fetal brain magnetic resonance imaging leading to the prenatal diagnosis of Joubert syndrome and related disorders.

Joubert syndrome is a rare autosomal recessive disorder characterized by ataxia, developmental delay, and oculomotor and respiratory abnormalities in relation to cerebellar vermian and midbrain dysgenesis. The midbrain dysgenesis is responsible for the molar tooth sign on axial magnetic resonance imaging (MRI). This classic hallmark of Joubert syndrome has been identified in other disorders sharing overlapping clinical and radiologic features with Joubert syndrome. Recent identification of two different genes points to genetic heterogeneity in this group of disorders, now entitled Joubert syndrome and related disorders, making a genetic prenatal diagnosis not readily available. In addition, fetal ultrasonography lacks sensitivity in regard to posterior fossa malformation. Fetal MRI is now acknowledged as the method of choice to delineate posterior fossa malformation in a fetus. The identification of a molar tooth sign has, however, rarely been documented by a fetal brain MRI. We report a case of Joubert syndrome diagnosed prenatally using fetal MRI. We also discuss the etiology of Joubert syndrome in view of the recent genetic advances and murine models of cerebellar dysgenesis.

Cheiro-oral-pedal syndrome due to brainstem hemorrhage.

Cheiro-oral-pedal syndrome is characterized by specific sensory disturbance around the corner of the mouth, in the hand and in the foot on the same side. Lesions responsible for causing this syndrome vary. We report two cases of cheiro-oral-pedal syndrome due to midbrain and pontine hemorrhage, respectively. Pontine hemorrhage producing cheiro-oral-pedal syndrome has been reported in three cases, but this is the first case that midbrain hematoma exhibits this syndrome. Damage in the sensory pathway can cause cheiro-oral-pedal syndrome. Difference in the threshold may explain the specific sensory pattern in this syndrome. Cheiro-oral-pedal syndrome is caused by lacunar infarction in majority of the cases. However, it should be kept in mind that hematomas can cause cheiro-oral-pedal syndrome.

Uncrossed epileptic seizures in Joubert syndrome.

Joubert syndrome and related disorders comprise a subgroup of ciliopathies defined by the presence of the 'molar tooth sign', a midbrain-hindbrain malformation identifiable by neuroimaging. Characteristically, the corticospinal tract and superior cerebellar peduncles do not decussate. Epileptic seizures are uncommon. We present a case of a 28-year-old man with a background of Leber's congenital amaurosis with nephronophthisis, requiring kidney transplantation, and mental retardation, who developed epileptic seizures consisting of a short muffled cry and involuntary shaking movements of the extremities beginning in the left upper limb; these episodes lasted several seconds and occurred in clusters. Simultaneous video-EEG recording showed an ictal pattern in the left frontal lobe. Brain MRI revealed the pathognomonic 'molar tooth sign'; diffusion tensor imaging (DTI)-tractography showed a lack of decussation of both corticospinal tracts. To the best of our knowledge, this is the first time that DTI-tractography has been used to uncover the anatomical substrate underlying the semiology of epileptic seizures.

Molar tooth sign in Joubert syndrome: clinical, radiologic, and pathologic significance.

Joubert syndrome is a rare autosomal-recessive condition characterized by early hyperpnea and apnea, developmental delay, and truncal ataxia. We previously described key ocular motor signs in Joubert syndrome and the molar tooth sign resulting from dysplasia of the isthmic segment of the brain stem, superior cerebellar peduncles, and vermis. In this study, we obtained clinical and developmental data in 61 cases, and radiologic data in 46 of these, to determine the prevalence of the molar tooth sign in a large sample, and to ensure that magnetic resonance images obtained for study were representative of the Joubert syndrome population at large. We studied the morphology of the isthmic segment of the pontomesencephalic junction, the segment of the brain stem derived from the primitive isthmus. Portions of the cerebellum analyzed included the superior cerebellar peduncles, the anterior and posterior lobes of the vermis, and the flocculonodular lobe. In one case, autopsy of the brain was performed. The average age at diagnosis was 33 months. All patients were hypotonic and developmentally delayed. The molar tooth sign was present in 85% of cases with 13% of these showing additional malformations. All patients without the molar tooth sign had other mimicking conditions such as neocerebellar dysgenesis, isolated vermian atrophy, cerebellar aplasia, and cystic dilation of the cisterna magna. Autopsy showed aplasia of the cerebellar vermis with dysplasia of the dentate nucleus, elongated locus coeruleus, and marked dysplasia of the caudal medulla. A better understanding of the clinical, radiologic, and pathologic features of Joubert syndrome should help uncover the genetic basis for the syndrome.

Quantitative assessment of brainstem development in Joubert syndrome and Dandy-Walker syndrome.

Key features of Joubert syndrome include developmental delay, hypotonia, hyperpnea and apnea, oculomotor apraxia, and the presence of the molar tooth sign on axial imaging through the brainstem isthmus--the junction of the pons and mesencephalon. Interestingly, 1 in 10 patients with Joubert syndrome has abnormal cerebrospinal fluid collections misdiagnosed as Dandy-Walker variants. Because of important differences in patient management, genetic counseling, and prognosis between these conditions, we undertook a study to determine if the brainstem isthmus is normal in Dandy-Walker syndrome. Using standard landmarks, we evaluated development of the isthmus in normal subjects and in subjects with Joubert syndrome and Dandy-Walker syndrome. Four of five brainstem measures increased with age in normal subjects. In subjects with Joubert syndrome, the depth and length of the interpeduncular fossa were increased, and the width of the isthmus was decreased. In subjects with Dandy-Walker syndrome, the width of the brainstem isthmus was normal, and the molar tooth sign was absent. Although the pons can be hypoplastic in Dandy-Walker syndrome, we conclude that the pontomesencephalic junction is normal. Thus, the molar tooth sign can effectively distinguish between Joubert and Dandy-Walker syndromes. Genetic heterogeneity or epigenetic factors may account for abnormal cerebrospinal fluid collections in some cases of Joubert syndrome.

[Change in trigeminal mesencephalic neurons after teeth extraction in guinea pig].

Trigeminal mesencephalic (Mes V) neurons innervating the periodontal mechanoreceptor (PMR) are known to play an important role in controlling the bite force and jaw-movements during mastication. After teeth loss, the PMR disappears due to loss of the periodontal membrane. The present work is a study on whether cell death is induced in the Mes V neurons in association with teeth loss. The upper and lower incisors were extracted on the right side in 5 guinea pigs (extraction group) and the other 5 guinea pigs were kept intact (control group). In the extraction group, the animals were kept alive for 58-119 days after teeth extraction. Serial coronal sections (50 microns thick) were made of the midbrain and pons and stained with cresyl violet. The Mes V neurons were counted on every other section. In the caudal half of the Mes V nucleus, where the neurons innervating the PMR are reported to be located, the number of neurons was less on the right side than on the left side (P < 0.01) in the extraction group, while there was no difference between the right and left sides in the control group. We conclude that teeth extraction can induce cell death in the Mes V neurons innervating the PMR and produce a significant change in the brainstem mechanisms controlling mastication.

Description and validation of a magnetic resonance imaging-guided stereotactic brain biopsy device in the dog.

A stereotactic brain biopsy system that is magnetic resonance (MR) imaging-guided has not been validated in dogs. Our purpose was to determine the mean needle placement error in the caudate nucleus, thalamus, and midbrain of a canine cadaver brain using the modified Brainsight stereotactic system. Relocatable reference markers (fiducial markers) were attached to the cadaver head using a dental bite block. A T1-weighted gradient echo three-dimensional (3D) sequence was acquired using set parameters. Fiducial markers were used to register the head to the acquired MR images in reference to a 3D position sensor. This allowed the planning of trajectory path to brain targets in real time. Coordinates (X, Y, Z) were established for each target and 0.5 microl of diluted gadolinium was injected at each target using a 26-gauge needle to create a lesion. The center of the gadolinium deposition was identified on the postoperative MR images and coordinates (X', Y', Z') were established. The precision of this system in bringing the needle to target (needle placement error) was calculated. Seventeen sites were targeted in the brain. The mean needle placement error for all target sites was 1.79 +/- 0.87 mm. The upper bound of error for this stereotactic system was 3.31 mm. There was no statistically significant relationship between needle placement error and target depth (P = 0.23). The ease of use and precision of this stereotactic system support its development for clinical use in dogs with brain lesions > 3.31 mm.

Progressive supranuclear palsy with palatal myoclonus.

We present a case of progressive supranuclear palsy (PSP) with palatal myoclonus occurred in a 64-year-old man. The nucleus olivaris of the medulla oblongata showed high signal intensity on T2-weighted MR images, indicating brainstem tegmental atrophy, which were confirmed as hypertrophy of the nucleus inferior olivaris at autopsy. The characteristic neuropathological findings were marked grumose degeneration of the dentate nucleus, degeneration and gliosis of the superior cerebellar peduncle, and hypertrophy of the bilateral olivary nuclei. As far as we know, although a few cases of PSP with olivary hypertrophy have been described, only one case has presented with palatal myoclonus.

Permanent bruxism as a manifestation of the oculo-facial syndrome related to systemic Whipple's disease.

We report here a new case of oculomasticatory syndrome related to systemic Whipple's disease. The patient presented typical ophthalmoparesis associated with ocular myorhythmia consisting of 1 Hz convergent oscillations of both eyes. The masticatory involvement was remarkable and consisted of a permanent bruxism leading to severe tooth abrasions. Possible pathophysiology of such a disorder is discussed.

Equine herpesvirus 9 induced lethal encephalomyelitis in experimentally infected goats.

The pathogenicity of a new neurotropic equine herpesvirus 9 (EHV-9) formerly designated gazelle herpesvirus 1 was evaluated using the goat as a representative of domesticated ruminants. Two goats inoculated intranasally with EHV-9 showed salivation, teeth grinding and other neurological disorders on day 8 post inoculation. One goat died 30 min after the onset of clinical signs and the other was sacrificed 3 h after the sudden onset of teeth grinding and foamy salivation. EHV-9 was recovered from peripheral white blood cells, the olfactory bulbs and brain, nasal swabs, concha, and lungs. Neuropathological lesions were located in the olfactory bulbs, cerebrum, midbrain and medulla oblongata with degeneration and necrosis of neurons, rarefaction, perivascular infiltration of mononuclear cells, and nodal glial reaction. EHV-9 antigen was detected in neurons in the lesions. These findings indicated that EHV-9 is highly pathogenic with high neurotropism for goats.

Markedly severe dystonia in Japanese encephalitis.

Encephalitis has been reported to be a rare cause of severe dystonia. We describe five patients with markedly severe dystonia from Japanese encephalitis. These patients with markedly severe dystonia were seen during the past 8 years as a subgroup of 50 patients with Japanese encephalitis. The diagnosis of markedly severe dystonia was based on increasingly frequent episodes of generalized dystonia with bulbar, respiratory, or metabolic derangement or leading to exhaustion or pain. The diagnosis of JE was based on clinicoradiologic features and a fourfold increase of hemagglutination-inhibiting antibody titers in paired serum. The outcome of the patients was defined as a good, partial, or poor recovery on the basis of 1-year clinical status. All the patients were males, and their ages ranged from 6 to 19 years. Movement disorders appeared 1 to 3 weeks after the illness as the level of consciousness started improving. During the next 1 to 4 weeks, patients began to experience markedly severe dystonia. It was associated with marked axial dystonia resulting in opisthotonus and retrocollis in five patients, jaw-opening dystonia in two patients, teeth clenching in one patient, and oculogyric crisis and neck deviation in another patient. The attacks of markedly severe dystonia lasted for 2 to 30 minutes and occurred as many as 20 to 30 times daily. Other developments included fixed limb dystonia in one patient, severe spasticity and rigidity in five patients, and focal muscle wasting in one patient. These patients had only a modest improvement after treatment. Markedly severe dystonia abated by 2 to 6 months in all the patients who were followed up. Cranial magnetic resonance imaging showed bilateral thalamic involvement in all patients, brainstem involvement in three patients, and basal ganglia involvement in two patients. At the 3-month follow-up, all patients had a poor outcome. At 1 year, one patient had a complete recovery; one had a partial recovery; and two were bedridden. It can be concluded that markedly severe dystonia is an important and serious sequela of Japanese encephalitis and may occur as the result of thalamus, midbrain, or basal ganglia involvement in various combinations.

Myorhythmia: a widespread movement disorder. Clinicopathological correlations.

The clinical manifestations of 24 cases and the autopsy findings of 6 cases of extremity myorhythmia are presented. Extremity myorhythmia is that form of myorhythmia in which rhythmic alternating movements predominantly involve the limbs. The main difference between the tremor of extremity myorhythmia and the tremor of parkinsonism is the slower tremor rate, 2 to 3 cycles/s in myorhythmia and 4 to 6 cycles/s in parkinsonism. The mechanograms, except for the slower frequencies in myorhythmia, can be very similar, including sinusoidal oscillation patterns in both conditions. Myorhythmia may be defined as a coarse, alternating tremor, present at rest and usually during movement, which occurs at rates varying from 50 to 240 oscillations/min but mostly at either 120 to 140 or 160 to 180 cycles/min. The alternating movements may be intermittent or continuous or both types may be present in different body parts. When multiple parts are involved, synchronous or asynchronous movements are about equally common. Movements are usually relatively rhythmic and regular but may vary over periods of time in rate, rhythm or amplitude and rarely so, even over the course of a few hours and are absent during sleep. Movements may involve single limbs, several limbs or a combination of limbs plus face, palate, head, jaw, neck, tongue, eyes or trunk. The frequency of the movements in the 24 cases varied from 120 to 180 oscillations/min with two exceptions the slowest being 60 and the fastest 240, with most tending to cluster near either 120 or 180 cycles/min. The most common aetiologies were brainstem vascular disease and cerebellar degeneration secondary to chronic alcoholism-nutritional deficiency. The best prognosis occurred in the latter group. Clinicopathological correlations in our autopsy series indicate that myorhythmia of the limbs may occur ipsilateral to the dentate nucleus or superior cerebellar peduncle lesions or contralateral to inferior olive involvement. Unilateral lesions of the dentate nucleus may result in bilateral limb movements and bilateral dentate lesions may be associated with unilateral limb movements. The frequent involvement of the cerebellum and the substantia nigra suggests possible roles for the cerebellum and substantia nigra in the myorhythmia process.