Severe Neurological Abnormalities Research Articles

Structural and Calorimetric Studies Demonstrate that Xeroderma Pigmentosum Type G (XPG) Can Be Imported to the Nucleus by a Classical Nuclear Import Pathway via a Monopartite NLS Sequence

Xeroderma pigmentosum type G (XPG) proteins are involved in DNA lesion recognition and promotion of nucleotide excision repair. Specific mutations in these proteins may lead to Cockayne syndrome, in which the patients may display severe developmental retardation and neurological abnormalities. No structural information is available for their spacer region or the C-terminal domain, which are important, respectively, for specific nucleotide excision repair activity and substrate specificity, as well as nuclear translocation. Immunofluorescence studies suggested two specific regions of the XPG C-terminus as potential bipartite nuclear localization sequences, which would be responsible for its translocation to the nucleus by the classical nuclear import pathway mediated by the importin‐α (Impα). Thus, in order to test these hypotheses and gain insight into the structural basis for the nuclear import process for the XPG protein, we solved the crystal structures of complexes formed by the Impα and peptides corresponding to both putative nuclear localization signal (NLS) sequences (XPG1 and XPG2) and performed isothermal titration calorimetry assays to determine their binding affinities. Structural experiments confirm the binding of both NLS peptides to Impα but, unexpectedly, they bind to the receptor as monopartite NLSs. The isothermal titration calorimetry assays demonstrated that XPG1 and XPG2 peptides bind to two separate binding sites, but with high affinity to the major NLS-binding site of the Impα, resembling classical monopartite SV40 TAg NLS. The results lead to insights about what distinguishes monopartite and bipartite NLSs, as well as the differential roles of XPG1 and XPG2 NLSs in the nuclear localization of XPG.

Prevalence and Phylogenetic Characterization of Enterovirus D68 in Pediatric Patients with Acute Respiratory Tract Infection in Thailand.

Enterovirus D68 (EV-D68) is associated with severe lower respiratory tract infection and neurological abnormalities including acute myelitis and cranial nerve dysfunction. To determine whether an increased incidence of EV-D68 occurs in Southeast Asia, we retrospectively tested specimens collected from Thai pediatric patients who were less than 5 years of age and presented with acute respiratory tract infections between 2012 and 2014. Reverse transcription-polymerase chain reaction and nucleotide sequencing of the 5'-UTR/VP2 region were used to identify EV-D68. We also examined the epidemiological pattern of EV-D68 since 2009, when it was first identified in Thailand, and compiled records of clinical manifestations in children with confirmed EV-D68 infection. From 837 samples, 5 samples (0.6%) tested positive for EV-D68. All patients presented with viral pneumonia and required hospitalization. Phylogenetic analysis of the VP4/VP2 regions revealed that EV-D68 strains circulating in Thailand between 2012 and 2014 were closely related to strains reported in Japan, United Kingdom, China, and France. Continued surveillance of probable EV-D68-associated severe respiratory tract infection and the development of a rapid diagnostic test for EV-D68 are essential in supporting awareness and facilitating disease prevention and control.

Three-decade neurological and neurocognitive follow-up of HIV-1-infected patients on best-available antiretroviral therapy in Finland

ObjectivesIs it possible to live without neurocognitive or neurological symptoms after being infected with HIV for a very long time? These study patients with decades-long HIV infection in Finland were...

A novel nine base deletion mutation in NADH-cytochrome b5 reductase gene in an Indian family with recessive congenital methemoglobinemia-type-II

Recessive hereditary methemoglobinemia (RCM) associated with severe neurological abnormalities is a very rare disorder caused by NADH- cytochrome b5 reductase (cb5r) deficiency (Type II). We report a case of 11month old male child who had severe mental retardation, microcephaly and gross global developmental delay with methemoglobin level of 61.1%. The diagnosis of NADH-CYB5R3 deficiency was made by the demonstration of significantly reduced NADH-CYB5R3 activity in the patient and intermediate enzyme activity in both the parents. Mutation analysis of the CYB5R gene revealed a novel nine nucleotide deletion in exon 6 leading to the elimination of 3 amino acid residues (Lys173, Ser174 and Val 175). To confirm that this mutation was not an artifact, we performed PCR-RFLP analysis using the restriction enzyme Drd I. As the normal sequence has a restriction recognition site for Drd I which was eliminated by the deletion, a single band of 603-bp was seen in the presence of the homozygous mutation. Molecular modeling analysis showed a significant effect of these 3 amino acids deletion on the protein structure and stability leading to a severe clinical presentation. A novel homozygous 9 nucleotide deletion (p.K173–p.V175del3) is shown to be segregated with the disease in this family. Knowing the profile of mutations would allow us to offer prenatal diagnosis in families with severe neurological disorders associated with RCM — Type II.

Role of Trifunctional Enzyme MTHFD1 in Maintenance of DNA Stability

MTHFD1 is a trifunctional enzyme possessing methyleneTHF dehydrogenase (D), methenylTHF cyclohydrolase (C) and formylTHF synthetase (S) activities. We have recently demonstrated that MTHFD1 translocates to the nucleus in S phase where it plays a key enzymatic role providing one‐carbon units for dTMP synthesis. An inborn error of metabolism associated with mutations in the human methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) gene has been recently identified. The proband presented with severe combined immune deficiency (SCID), megaloblastic anemia and neurologic abnormalities. In this study, we examined the impact of MTHFD1 loss‐of‐function on DNA stability. Patient fibroblasts exhibited increased DNA damage relative to control fibroblasts. γH2AX levels, a marker of double‐strand breaks in DNA, were markedly increased in MTHFD1‐deficient patient fibroblasts relative to both control lines as well as the adenosine deaminase deficient fibroblast lines. γH2AX staining increased in patient fibroblasts when cultured in folate‐deficient medium as compared to fibroblasts cultured in folate‐replete medium, indicating that the MTHFD1‐deficient fibroblasts are sensitized to folate deficiency‐induced DNA damage.

Consequences of impaired purine recycling on the proteome in a cellular model of Lesch-Nyhan disease.

The importance of specific pathways of purine metabolism for normal brain function is highlighted by several inherited disorders, such as Lesch-Nyhan disease (LND). In this disorder, deficiency of the purine recycling enzyme, hypoxanthine-guanine phosphoribosyltransferase (HGprt), causes severe neurological and behavioral abnormalities. Despite many years of research, the mechanisms linking the defect in purine recycling to the neurobehavioral abnormalities remain unclear. In the current studies, an unbiased approach to the identification of potential mechanisms was undertaken by examining changes in protein expression in a model of HGprt deficiency based on the dopaminergic rat PC6-3 line, before and after differentiation with nerve growth factor (NGF). Protein expression profiles of 5 mutant sublines carrying different mutations affecting HGprt enzyme activity were compared to the HGprt-competent parent line using the method of stable isotopic labeling by amino acids in cell culture (SILAC) followed by denaturing gel electrophoresis with liquid chromatography and tandem mass spectrometry (LC-MS/MS) of tryptic digests, and subsequent identification of affected biochemical pathways using the Database for Annotation, Visualization and Integrated Discovery (DAVID) functional annotation chart analysis. The results demonstrate that HGprt deficiency causes broad changes in protein expression that depend on whether the cells are differentiated or not. Several of the pathways identified reflect predictable consequences of defective purine recycling. Other pathways were not anticipated, disclosing previously unknown connections with purine metabolism and novel insights into the pathogenesis of LND.

Fact or Fiction? Examining a Role for N-Methyl-D-Aspartate Receptor Autoantibodies in Psychiatric Illness

Fact or Fiction? Examining a Role for N-Methyl-D-Aspartate Receptor Autoantibodies in Psychiatric Illness

De Novo Mutations in NALCN Cause a Syndrome Characterized by Congenital Contractures of the Limbs and Face, Hypotonia, and Developmental Delay

Freeman-Sheldon syndrome, or distal arthrogryposis type 2A (DA2A), is an autosomal-dominant condition caused by mutations in MYH3 and characterized by multiple congenital contractures of the face and limbs and normal cognitive development. We identified a subset of five individuals who had been putatively diagnosed with "DA2A with severe neurological abnormalities" and for whom congenital contractures of the limbs and face, hypotonia, and global developmental delay had resulted in early death in three cases; this is a unique condition that we now refer to as CLIFAHDD syndrome. Exome sequencing identified missense mutations in the sodium leak channel, non-selective (NALCN) in four families affected by CLIFAHDD syndrome. We used molecular-inversion probes to screen for NALCN in a cohort of 202 distal arthrogryposis (DA)-affected individuals as well as concurrent exome sequencing of six other DA-affected individuals, thus revealing NALCN mutations in ten additional families with "atypical" forms of DA. All 14 mutations were missense variants predicted to alter amino acid residues in or near the S5 and S6 pore-forming segments of NALCN, highlighting the functional importance of these segments. In vitro functional studies demonstrated that NALCN alterations nearly abolished the expression of wild-type NALCN, suggesting that alterations that cause CLIFAHDD syndrome have a dominant-negative effect. In contrast, homozygosity for mutations in other regions of NALCN has been reported in three families affected by an autosomal-recessive condition characterized mainly by hypotonia and severe intellectual disability. Accordingly, mutations in NALCN can cause either a recessive or dominant condition characterized by varied though overlapping phenotypic features, perhaps based on the type of mutation and affected protein domain(s).

A Challenging Form of Non-autoimmune Insulin-Dependent Diabetes in a Wolfram Syndrome Patient with a Novel Sequence Variant.

Wolfram syndrome type 1 is a rare, autosomal recessive, neurodegenerative disorder that is diagnosed when insulin-dependent diabetes of non-auto-immune origin and optic atrophy are concomitantly present. Wolfram syndrome is also designated by DIDMOAD that stands for its most frequent manifestations: diabetes insipidus, diabetes mellitus, optic atrophy and deafness. With disease progression, patients also commonly develop severe neurological and genito-urinary tract abnormalities. When compared to the general type 1 diabetic population, patients with Wolfram Syndrome have been reported to have a form of diabetes that is more easily controlled and with less microvascular complications, such as diabetic retinopathy.We report a case of Wolfram syndrome in a 16-year-old male patient who presented with progressive optic atrophy and severe diabetes with very challenging glycemic control despite intensive therapy since diagnosis at the age of 6. Despite inadequate metabolic control he did not develop any diabetic microvascular complications during the 10-year follow-up period. To further investigate potential causes for this metabolic idiosyncrasy, we performed genetic analyses that revealed a novel combination of homozygous sequence variants that are likely the cause of the syndrome in this family. The identified genotype included a novel sequence variant in the Wolfram syndrome type 1 gene along with a previously described one, which had initially been associated with isolated low frequency sensorineural hearing loss (LFSNHL). Interestingly, our patient did not show any abnormal findings with audiometry testing.

Asymptomatic maternal 3-methylcrotonylglycinuria detected by her unaffected baby's neonatal screening test.

3-methylcrotonyl-coenzyme A carboxylase (3MCC) deficiency is an autosomal recessive disorder in which leucine catabolism is hampered, leading to increased urinary excretion of 3-methylcrotonylglycine. In addition, 3-hydroxyisovalerylcarnitine levels increase in the blood, and the elevated levels form the basis of neonatal screening. 3MCC deficiency symptoms are variable, ranging from neonatal onset with severe neurological abnormality to a normal, asymptomatic phenotype. Although 3MCC deficiency was previously considered to be rare, it has been found to be one of the most common metabolic disorders in newborns after the neonatal screening test using tandem mass spectrometry was introduced. Additionally, asymptomatic 3MCC deficient mothers have been identified due to abnormal results of unaffected baby's neonatal screening test. Some of the 3MCC-deficient mothers show symptoms such as fatigue, myopathy, or metabolic crisis with febrile illnesses. In the current study, we identified an asymptomatic 3MCC deficient mother when she showed abnormal results during a neonatal screening test of a healthy infant.

Glucose Phosphate Isomerase Deficiency In 2 Patients With Novel Mutations Presenting As Severe Neurologic Abnormalities and Transfusion Dependent Hemolytic Anemia

▪ IntroductionGlucose phosphate isomerase (GPI) deficiency is the third most common red cell enzymopathy. GPI is an enzyme that reversibly catalyzes the conversion of glucose-6-phosphate into fructose 6-phosphate in the second step of glycolysis. Patients afflicted by GPI deficiency have chronic hemolysis and may also suffer from acute hemolytic crises. There are 184 known mutations of the GPI gene and to date, a neurological deficit is found in only five patients and only two of these have been characterized at a molecular level. We report 2 patients with previously unknown mutations of the GPI gene associated with, severe neurologic abnormalities and hemolytic anemia. Case 1He was born at 38 weeks gestation; marked pallor and hepatosplenomegaly were noted at birth. The bilirubin was elevated at birth (indirect 7.5 mg/dl and direct 2.2mg/dl) requiring phototherapy. He has transfusion dependent anemia since birth. Enzymes studied were performed which showed GPI levels of 2.02 EU/gm hb ( normal range 16.3-24.7 ) and elevated glucose 6 phosphate dehydrogenase , pyruvate kinase and hexokinase. The pyrimidine 5'-nucleotidase screen was normal. In his subsequent course, he started to have seizures at 6 months of age, refractory to anticonvulsant therapy. He has severe hypotonia and global developmental delay. Magnetic resonance imaging of the brain showed generalized cerebral atrophy with no evidence of kernicterus. Case 2He was noted to have anemia and marked hepatosplenomegaly at birth. He required exchange transfusions and phototherapy in the neonatal period. He has subsequently suffered from lifelong transfusion-dependent hemolytic anemia. He also suffers from developmental delay, ataxia, spasticity, and seizures. Of note, MRI did not exhibit evidence of kernicterus.Table. Mutations of the GPI gene in both the patientsMutation : Change in amino acid and locationLocation of amino acid in GPI crystal structureCarrier parentCASE 1Histidine to arginine at codon 191 (H191R)located in alpha helix tenFatherGlycine to tryptophan at codon 381 (G381W)located in beta sheet fourMotherCASE 2Arginine to glutamine at codon 104 (R104Q)boundary of alpha helix sevenMotherLeucine to phenylalanine at codon 297 (L297F).located in alpha helix fifteenFatherThe mutations were predicted to be pathogenic (probably damaging) by PolyPhen. Both these mutations were in a highly conserved residue. Genetic probe for preimplantation diagnosis is being used for selection of an embryo which is does not have GPI deficiency and is also a potential HLA match with the hope of undergoing hematopoietic stem cell transplantation to avoid the complications of chronic transfusions and iron overload. DiscussionGPI has many functions. In dimeric form, it exhibits its catalytic function. In monomeric form, it acts as a neurotrophic growth factor, neuroleukin, which in vitro promotes survival of neurons. Abnormalities in neuroleukin have been found in motor neuron disease and in patients with central nervous system abnormalities in patients with acquired immunodeficiency disease. These effects of GPI/neuroleukin and relative deficiency in brain and neurons of this protein may explain the neurologic presentation. Decreased phosphatide phosphatase 1 activity, a lipogeneic enzyme due to mTOR activation by accumulated glucose-6-phosphate has been suggested to contribute to the neurologic symptoms. Why some of these mutation are associated with neurologic deficits while most others are not is not known. It has been speculated that the mutations which affect the folding may cause altered structure and function causing neurologic symptoms as well as hemolytic anemia while mutations affecting the catalytic site presents only as hemolytic anemia without neurologic symptoms. Disclosures:No relevant conflicts of interest to declare.

Mutational spectrum of Xeroderma pigmentosum group A in Egyptian patients

Xeroderma pigmentosum (XP) is a rare autosomal recessive hereditary disease characterized by hyperphotosensitivity, DNA repair defects and a predisposition to skin cancers. The most frequently occurring type worldwide is the XP group A (XPA). There is a close relationship between the clinical features that ranged from severe to mild form and the mutational site in XPA gene. The aim of this study is to carry out the mutational analysis in Egyptian patients with XP-A. This study was carried out on four unrelated Egyptian XP-A families. Clinical features were examined and direct sequencing of the coding region of XPA gene was performed in patients and their parents. Direct sequencing of the whole coding region of the XPA gene revealed the identification of two homozygous nonsense mutations: (c.553C>T; p.(Gln185*)) and (c.331G>T; p.(Glu111*)), which create premature, stop codon and a homodeletion (c.374delC: p.Thr125Ilefs*15) that leads to frameshift and premature translation termination. We report the identification of one novel XPA gene mutation and two known mutations in four unrelated Egyptian families with Xermoderma pigmentosum. All explored patients presented severe neurological abnormalities and have mutations located in the DNA binding domain. This report gives insight on the mutation spectrum of XP-A in Egypt. This would provide a valuable tool for early diagnosis of this severe disease.

Clinical Spectrum of LIG 4 Deficiency Is Broadened with Severe Dysmaturity, Primordial Dwarfism, and Neurological Abnormalities

DNA double-strand break repair via non-homologous end joining (NHEJ) is involved in recombination of immunoglobulin and T-cell receptor genes. Mutations in NHEJ components result in syndromes that are characterized by microcephaly and immunodeficiency. We present a patient with lymphopenia, extreme radiosensitivity, severe dysmaturity, corpus callosum agenesis, polysyndactily, dysmorphic appearance, and erythema, which are suggestive of a new type of NHEJ deficiency. We identified two heterozygous mutations in LIG4. The p.S205LfsX29 mutation results in lack of the nuclear localization signal and appears to be a null mutation. The second mutation p.K635RfsX10 lacks the C-terminal region responsible for XRCC4 binding and LIG4 stability and activity, and therefore this mutant might be a null mutation as well or have very low residual activity. This is remarkable since Lig4 knockout mice are embryonic lethal and so far in humans no complete LIG4 deficiencies have been described. This case broadens the clinical spectrum of LIG4 deficiencies.

Uncommon Leber “Plus” Disease Associated With Mitochondrial Mutation m.11778G>A in a Premature Child

Leber hereditary optic neuropathy is a well-known mitochondrial disorder that leads to bilateral subacute visual failure. Although visual impairment is often the sole clinical feature, additional and severe neurologic abnormalities also have been documented for this disease. We report on a 13-year-old boy who has presented with severe visual failure since early childhood in a context of prematurity. In the first years of his life, clinical features included delayed psychomotor development and ataxia. The clinical presentation, which was initially attributed to prematurity, worsened thereafter, and the child developed acute neurologic degradation with the typical radiological findings of Leigh syndrome. The mitochondrial DNA point mutation 11778G>A was identified in the ND4 gene. The probable influence of environmental background on clinical expression of Leber optic neuropathy, particularly those of prematurity and oxygen therapy, is discussed in our manuscript.

Prenatal Diagnosis and Management of a Huge Infratentorial/Supratentorial Multiloculated Arachnoid Cystic Malformation in an Infant

A 23-year-old woman had a normal fetal ultrasound at 16 weeks’ gestation. A second ultrasound at 25 weeks revealed a cystic brain malformation in the fetus. A fetal magnetic resonance image (MRI) at 28 weeks showed the presence of a huge infratentorial/supratentorial multiloculated arachnoid cystic malformation and hydrocephalus (Fig 1A) [1]. Although the prognosis was highly uncertain, the possibility of blindness, endocrine abnormalities, and severe developmental delay was discussed with the family. At 38 weeks, an infant boy was delivered via elective cesarian section with Apgar scores of 8 and 9 at 1 and 5 minutes, respectively. Other than macrocephaly with full fontanelles, the physical examination was normal and without evidence of diabetes insipidus. A postdelivery MRI found the cystic malformation to have enlarged when compared with the fetal study (Fig 1B). A craniotomy was performed to fenestrate this multiloculated cystic malformation [2]. Histology of the submitted tissue was arachnoid. No problems were encountered postoperatively, and the infant was discharged home where growth and development progressed normally and the head circumference diminished by 50%. At 6 months an MRI (Fig 1C) showed an increase in size of the third ventricle and both lateral ventricles when compared with the MRI performed just after the fenestration. As continued enlargement was expected, a second operative procedure was performed consisting of an endoscopic cyst fenestration and third ventriculostomy. At 9 months of age, an MRI (Fig 1D) showed a decrease in the size of the cyst and lateral ventricles. At 1 year of age, his cognitive function appears mildly delayed. His vision is grossly normal; ocular motility is full, conjugate, and free of nystagmus. Tone and strength are normal and without focal deficit. The fetal MRI alerted the family to the presence of this huge multiloculated arachnoid cystic malformation that could be associated with severe neurologic and endocrinologic abnormalities. These cysts frequently enlarge, as was evident with this infant who has done remarkably well considering the magnitude of the cystic malformation. Figure 1. (A) Antenatal sagittal magnetic resonance image (MRI) at 28 weeks’ gestation demonstrated a large infratentorial/supratentorial multiloculated cystic malformation displacing the brainstem superiorly and posteriorly. (B) Postnatal T2-weighted sagittal MRI showed this suprasellar-prepontine midline cyst extending into the posterior fossa to have enlarged when compared with the fetal study. (C) Follow-up T1-weighted sagittal MRI at 6 months of age showed the third ventricular cyst and lateral ventricles had increased in size compared with the immediate postoperative MRI following the initial fenestration procedure (not shown). (D) Follow-up T2-weighted sagittal MRI at 9 months of age showed a decrease in the size of the cyst and ventricles following endoscopic cyst fenestration and third

Neurodevelopmental Outcomes of Children with Periventricular Leukomalacia

To examine the neurodevelopmental outcomes of children with periventricular leukomalacia (PVL). Twenty-five children diagnosed with grade 1, 2 or 3 PVL on the basis of magnetic resonance imaging (MRI) findings between January 2002 and December 2011 were enrolled and followed from 15 months to 10 years of age. Of the 25 children, one was a term and 24 were preterm-births. Nine (36%) had spastic diplegia and 12 (48%) had quadriplegia. Ten of the 25 (40%) were able to walk independently at 36 months utilizing short leg braces, whereas 13 children (52%) were unable to walk independently. MRI findings revealed grade 1 PVL in nine (36%), grade 2 in 12 (48%), and grade 3 in four (16%) of the 25 children. Eleven of the 16 children (69%) with grade 2 or 3 PVL had Papile III or IV intraventricular hemorrhage (IVH), and many of these children had severe neurologic motor abnormalities, severe psychomotor delay, and seizures. Five of the nine children (56%) with grade 1 PVL had normal psychomotor development. There were statistically significant differences in the motor impairment and walking ability between the children with grade 1 and those with grade 2 PVL (p=0.008 and 0.005, respectively). Most children with grade 2 or 3 PVL had severe neurodevelopmental delays, but attention should also be paid to the 56% of children with grade 1 PVL who presented with normal psychomotor development. Further studies of larger populations, including long-term follow-up, are necessary to evaluate the outcomes of children with PVL.

Identification, functional analysis, prevalence and treatment of monocarboxylate transporter 8 (MCT8) mutations in a cohort of adult patients with mental retardation

Monocarboxylate transporter 8 (MCT8) is an essential thyroid hormone (TH) transporter as humans with MCT8 mutations have severe neurological and endocrine abnormalities. The objectives are (i) to identify novel MCT8 mutations and (ii) to assess their functional relevance; (iii) to describe the effects of block-and-replace treatment in an MCT8 patient. The TOP-R study is a cross-sectional nation-wide multicentre study. Subjects with unexplained mental retardation (MR) were screened for MCT8 mutations. We identified three mutations: p.F501del (previously described), p.L492P and p.T162T. The F501del and L492P mutants, but not the T162T mutant, showed diminished T3, T4 and rT3 transport in transfected cells. TH transport in T162T fibroblasts was also not affected. One patient was treated with block-and-replace therapy to normalize serum TH levels. The results indicated a slow onset of the decrease in serum T4 and T3 by successive treatment with methimazole and PTU, and eventually their complete normalization by administration of LT4 with PTU but not with methimazole. The frequency of MCT8 mutations in males with X-linked MR approximately 3·9%. We identified several MCT8 mutations in a cohort of subjects with unexplained MR. We demonstrated the pathogenicity of two missense mutations. The synonymous variant did not affect TH transport. Block-and-replace therapy of one patient reversed the TH abnormalities. Our data suggest a decreased TH secretion rate and an increased T4 to T3 conversion by the type I deiodinase in patients with MCT8 mutations. Our study indicates that MCT8 mutations are a relatively frequent cause of X-linked MR.

Anatomic Olfactory Structural Abnormalities in Congenital Smell Loss

There are 2 groups of patients with congenital smell loss: group 1 (12% of the total), in which patients exhibit a familial smell loss in conjunction with severe anatomical, somatic, neurological, and metabolic abnormalities such as hypogonadotropic hypogonadism; and a larger group, group 2 (88% of the total), in which patients possess a similar degree of smell loss but without somatic, neurological, or anatomical abnormalities or hypogonadism. Both groups are characterized by similar olfactory dysfunction, and both have been reported to have absent or decreased olfactory bulbs and grooves, which indicates some overlap in olfactory pathophysiology and anatomy. The purpose of this study was to evaluate patients with congenital smell loss, primarily among group 2 patients, comparing brain magnetic resonance imaging (MRI) results in patients with types of hyposmia. Forty group 2 patients were studied by measurements of taste (gustometry) and smell (olfactometry) function and by use of MRI in which measurements of olfactory bulbs, olfactory sulcus depth, olfactory grooves, and hippocampal anatomy were performed. Anatomical results were compared with similar studies in group 1 patients and in 22 control subjects with normal sensory function. Olfactometry was abnormal in all patients with no patient reporting ever having normal olfaction. No patient had a familial history of smell loss. On MRI, all exhibited at least 1 abnormality in olfactory system anatomy, including absence or decreased size of at least 1 olfactory bulb, decreased depth of an olfactory sulcus, and abnormalities involving hippocampal anatomy with hippocampal malrotations. One patient had bilateral bulb duplication. Normal subjects with normal smell and taste function exhibited some but very few or significant neuroanatomical changes on MRI. Although both groups have similar abnormalities of smell function, group 2 patients demonstrate anatomical anomalies in olfactory structures that are neither as common nor as severe as in group 1 patients. Group 2 patients can have a wide range of olfactory anatomical abnormalities.

Induction of apoptotic death and retardation of neuronal differentiation of human neural stem cells by sodium arsenite treatment

Chronic arsenic toxicity is a global health problem that affects more than 100 million people worldwide. Long-term health effects of inorganic sodium arsenite in drinking water may result in skin, lung and liver cancers and in severe neurological abnormalities. We investigated in the present study whether sodium arsenite affects signaling pathways that control cell survival, proliferation and neuronal differentiation of human neural stem cells (NSC). We demonstrated that the critical signaling pathway, which was suppressed by sodium arsenite in NSC, was the protective PI3K–AKT pathway. Sodium arsenite (2–4μM) also caused down-regulation of Nanog, one of the key transcription factors that control pluripotency and self-renewal of stem cells. Mitochondrial damage and cytochrome-c release induced by sodium arsenite exposure was followed by initiation of the mitochondrial apoptotic pathway in NSC. Beside caspase-9 and caspase-3 inhibitors, suppression of JNK activity decreased levels of arsenite-induced apoptosis in NSC. Neuronal differentiation of NSC was substantially inhibited by sodium arsenite exposure. Overactivation of JNK1 and ERK1/2 and down-regulation of PI3K–AKT activity induced by sodium arsenite were critical factors that strongly affected neuronal differentiation. In conclusion, sodium arsenite exposure of human NSC induces the mitochondrial apoptotic pathway, which is substantially accelerated due to the simultaneous suppression of PI3K–AKT. Sodium arsenite also negatively affects neuronal differentiation of NSC through overactivation of MEK–ERK and suppression of PI3K–AKT.

Crowned dens syndrome

Introduction Microcrystalline deposition in peri-odontoid articular structures is mainly responsible for acute or chronic cervical pain and is known as “crowned dens syndrome”.Materials and methods We described two cases of acute cervical pain associated with onset of fever and peripheral acute monoarthritis. Cervical computed tomography (CT) scan showed linear calcification of the retrodens ligament and calcium pyrophosphate dehydrate (CPPD) crystals were found in synovial fluid of inflamed joints. Both patients were treated with anti-inflammatory drugs and colchicine.Discussion Calcium depositions around the odontoid process of the axis can be occasionally detected by radiological studies. They are frequently asymptomatic but sometimes can be associated with severe neurological abnormalities, fever and acute neck pain. CPPD crystals are usually deposited in joints and bursae but occasionally can disrupt these anatomical confines and deposit in periarticular tissues, sometimes forming large masses confused with tumours.Conclusions Acute onset of cervical neck pain associated with elevation of inflammatory indicators and/or signs of cervical myelopathy should suggest CT scans searching for microcrystal depositions in the peryodonthoid tissue. Differential diagnosis of fever of unknown origin (FUO) should include crowned dens syndrome specially in the elderly after exclusion of several endocrine or metabolic disorders, infection diseases (meningitis), arthritis (psoriatic arthritis and ankylosing spondylitis) and tumours (chordoma, meningioma, osteoblastoma).