Fetal neuroaxonal dystrophy: a further etiology of fetal akinesia

Neuroaxonal Dystrophies (NAD) are neurodegenerative diseases characterized by axonal "spheroids" occurring in different age groups. The identification of mutations delineated new molecular entities in these disorders. We report neuropathological data of a new form of NAD, characterized by a precocious prenatal onset, different from classical and conatal Infantile Neuroaxonal Dystrophy (INAD).We studied 5 fetuses examined after pregnancy termination and 2 term neonates deceased just after birth, 4/7 born from consanguineous parents. All subjects presented severe fetal akinesia sequence with microcephaly. In 4/7 cases, a molecular study was performed. In all cases, "spheroids" with typical immunohistochemical features were identified, with variable spreading in the central and peripheral nervous system. Basal ganglia, brainstem, cerebellum, and spinal cord involvement was constant. Associated CNS malformations, unusual in INAD, were associated including hydrocephalus (2), callosal agenesis/hypoplasia (2), olfactory agenesis (1), cortical (3) and retinal (1) anomalies. None of the cases demonstrated mutations in PLA2G6, found in INAD. The clinical and neuropathological features of these fetal cases are different from those of "classical" INAD. The absence of mutations in PLA2G6, in addition, suggests that the fetal NAD is a new entity, distinct from INAD, with different molecular basis. Associated malformations suggest a wide phenotypic spectrum and probable genetic heterogeneity. Finally, fetal NAD is an additional etiology of fetal akinesia.LEARNING OBJECTIVESThis presentation will enable the learner to:Diagnose this rare form of neuroaxonal dystrophy (NAD) occurring precociously, in the fetal life, as soon as the second trimester, different from the infantile form of NAD. 1.Describe the phenotypic spectrum of this fetal NAD; fetal akinesia sequence, microcephaly and various brain malformations, different from the "classical" and conatal forms of infantile neuroaxonal dystrophy.2.Consider this etiology in the diagnosis of fetal akinesia sequence

Defective migration of neuroendocrine GnRH cells in human arrhinencephalic conditions

Patients with Kallmann syndrome (KS) have hypogonadotropic hypogonadism caused by a deficiency of gonadotropin-releasing hormone (GnRH) and a defective sense of smell related to olfactory bulb aplasia. Based on the findings in a fetus affected by the X chromosome–linked form of the disease, it has been suggested that hypogonadism in KS results from the failed embryonic migration of neuroendocrine GnRH1 cells from the nasal epithelium to the forebrain. We asked whether this singular observation might extend to other developmental disorders that also include arrhinencephaly. We therefore studied the location of GnRH1 cells in fetuses affected by different arrhinencephalic disorders, specifically X-linked KS, CHARGE syndrome, trisomy 13, and trisomy 18, using immunohistochemistry. Few or no neuroendocrine GnRH1 cells were detected in the preoptic and hypothalamic regions of all arrhinencephalic fetuses, whereas large numbers of these cells were present in control fetuses. In all arrhinencephalic fetuses, many GnRH1 cells were present in the frontonasal region, the first part of their migratory path, as were interrupted olfactory nerve fibers that formed bilateral neuromas. Our findings define a pathological sequence whereby a lack of migration of neuroendocrine GnRH cells stems from the primary embryonic failure of peripheral olfactory structures. This can occur either alone, as in isolated KS, or as part of a pleiotropic disease, such as CHARGE syndrome, trisomy 13, and trisomy 18

Loss of VGLUT1 and VGLUT2 in the prefrontal cortex is correlated with cognitive decline in Alzheimer disease.

International audienceSeveral lines of evidence suggest that the glutamatergic system is severely impaired in Alzheimer disease (AD). Here, we assessed the status of glutamatergic terminals in AD using the first available specific markers, the vesicular glutamate transporters VGLUT1 and VGLUT2. We quantified VGLUT1 and VGLUT2 in the prefrontal dorsolateral cortex (Brodmann area 9) of controls and AD patients using specific antiserums. A dramatic decrease in VGLUT1 and VGLUT2 was observed in AD using Western blot. Similar decreases were observed in an independent group of subjects using immunoautoradiography. The VGLUT1 reduction was highly correlated with the degree of cognitive impairment, assessed with the clinical dementia rating (CDR) score. A significant albeit weaker correlation was also observed with VGLUT2. These findings provide evidence indicating that glutamatergic systems are severely impaired in the A9 region of AD patients and that this impairment is strongly correlated with the progression of cognitive decline. Our results suggest that VGLUT1 expression in the prefrontal cortex could be used as a valuable neurochemical marker of dementia in AD

Paclitaxel resistance by random mutagenesis of α‐tubulin

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102075/1/cm21154-sup-0001-suppfig1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102075/2/cm21154-sup-0002-suppfig2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102075/3/cm21154.pd

Role of cytoskeletal abnormalities in the neuropathology and pathophysiology of type I lissencephaly

Type I lissencephaly or agyria-pachygyria is a rare developmental disorder which results from a defect of neuronal migration. It is characterized by the absence of gyri and a thickening of the cerebral cortex and can be associated with other brain and visceral anomalies. Since the discovery of the first genetic cause (deletion of chromosome 17p13.3), six additional genes have been found to be responsible for agyria–pachygyria. In this review, we summarize the current knowledge concerning these genetic disorders including clinical, neuropathological and molecular results. Genetic alterations of LIS1, DCX, ARX, TUBA1A, VLDLR, RELN and more recently WDR62 genes cause migrational abnormalities along with more complex and subtle anomalies affecting cell proliferation and differentiation, i.e., neurite outgrowth, axonal pathfinding, axonal transport, connectivity and even myelination. The number and heterogeneity of clinical, neuropathological and radiological defects suggest that type I lissencephaly now includes several forms of cerebral malformations. In vitro experiments and mutant animal studies, along with neuropathological abnormalities in humans are of invaluable interest for the understanding of pathophysiological mechanisms, highlighting the central role of cytoskeletal dynamics required for a proper achievement of cell proliferation, neuronal migration and differentiation

Early microglial colonization of the human forebrain and possible involvement in periventricular white-matter injury of preterm infants

Amoeboid microglial subpopulations visualized by antibodies against ionized calcium-binding adapter molecule 1, CD68, and CD45 enter the forebrain starting at 4.5 postovulatory or gestational weeks (gw). They penetrate the telencephalon and diencephalon via the meninges, choroid plexus, and ventricular zone. Early colonization by amoeboid microglia-macrophages is first restricted to the white matter, where these cells migrate and accumulate in patches at the junctions of white-matter pathways, such as the three junctions that the internal capsule makes with the thalamocortical projection, external capsule and cerebral peduncle, respectively. In the cerebral cortex anlage, migration is mainly radial and tangential towards the immature white matter, subplate layer, and cortical plate, whereas pial cells populate the prospective layer I. A second wave of microglial cells penetrates the brain via the vascular route at about 12-13 gw and remains confined to the white matter. Two main findings deserve emphasis. First, microglia accumulate at 10-12 gw at the cortical plate-subplate junction, where the first synapses are detected. Second, microglia accumulate in restricted laminar bands, most notably around 19-30 gw, at the axonal crossroads in the white matter (semiovale centre) rostrally, extending caudally in the immature white matter to the visual radiations. This accumulation of proliferating microglia is located at the site of white-matter injury in premature neonates. The spatiotemporal organization of microglia in the immature white and grey matter suggests that these cells may play active roles in developmental processes such as axonal guidance, synaptogenesis, and neurodevelopmental apoptosis as well as in injuries to the developing brain, in particular in the periventricular white-matter injury of preterm infants. © 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.SCOPUS: ar.jFLWINinfo:eu-repo/semantics/publishe