Diana Rodriguez

RNASET2-deficient cystic leukoencephalopathy resembles congenital cytomegalovirus brain infection.

Congenital cytomegalovirus brain infection without symptoms at birth can cause a static encephalopathy with characteristic patterns of brain abnormalities. Here we show that loss-of-function mutations in the gene encoding the RNASET2 glycoprotein lead to cystic leukoencephalopathy, an autosomal recessive disorder with an indistinguishable clinical and neuroradiological phenotype. Congenital cytomegalovirus infection and RNASET2 deficiency may both interfere with brain development and myelination through angiogenesis or RNA metabolism.

Benign hereditary chorea: phenotype, prognosis, therapeutic outcome and long term follow-up in a large series with new mutations in the TITF1/NKX2-1 gene

Background Benign hereditary chorea (BHC) is a rare autosomal dominant disorder characterised by childhood onset that tends to improve in adulthood. The associated gene, NKX2-1 (previously called TITF1), is essential for organogenesis of the basal ganglia, thyroid and lungs. The aim of the study was to refine the movement disorders phenotype. We also studied disease course and response to therapy in a large series of genetically proven patients. Methods We analysed clinical, genetic findings and follow-up data in 28 NKX2-1 mutated BHC patients from 13 families. Results All patients had private mutations, including seven new mutations, three previously reported mutations and three sporadic deletions encompassing the NKX2-1 gene. Hypotonia and chorea were present in early infancy, with delayed walking ability (25/28); dystonia, myoclonus and tics were often associated. Attention deficit hyperactivity disorder (ADHD) was present in seven. Among the 14 patients followed-up until adulthood, nine had persistent mild chorea, two had near total resolution of chorea but persistent disabling prominent myoclonus and three recovered completely. Learning difficulties were observed in 20/28 patients, and three had mental retardation. Various combinations of BHC, thyroid (67%) and lung (46%) features were noted. We found no genotype–phenotype correlation. A rapid and sustained beneficial effect on chorea was obtained in 5/8 patients treated with tetrabenazine. Conclusion Early onset chorea preceded by hypotonia is suggestive of BHC. Associated thyroid or respiratory disorders further support the diagnosis and call for genetic studies. Tetrabenazine may be an interesting option to treat disabling chorea.

Mortality associated with neurofibromatosis 1: a cohort study of 1895 patients in 1980-2006 in France.

BackgroundNeurofibromatosis 1 (NF1), a common autosomal dominant disorder, was shown in one study to be associated with a 15-year decrease in life expectancy. However, data on mortality in NF1 are limited. Our aim was to evaluate mortality in a large retrospective cohort of NF1 patients seen in France between 1980 and 2006.MethodsConsecutive NF1 patients referred to the National French Referral Center for Neurofibromatoses were included. The standardized mortality ratio (SMR) with its 95% confidence interval (CI) was calculated as the ratio of observed over expected numbers of deaths. We studied factors associated with death and causes of death.ResultsBetween 1980 and 2006, 1895 NF1 patients were seen. Median follow-up was 6.8 years (range, 0.4-20.6). Vital status was available for 1226 (65%) patients, of whom 1159 (94.5%) survived and 67 (5.5%) died. Overall mortality was significantly increased in the NF1 cohort (SMR, 2.02; CI, 1.6-2.6; P < 10-4). The excess mortality occurred among patients aged 10 to 20 years (SMR, 5.2; CI, 2.6-9.3; P < 10-4) and 20 to 40 years (SMR, 4.1; 2.8-5.8; P < 10-4). Significant excess mortality was found in both males and females. In the 10-20 year age group, females had a significant increase in mortality compared to males (SMR, 12.6; CI, 5.7-23.9; and SMR, 1.8; CI, 0.2-6.4; respectively). The cause of death was available for 58 (86.6%) patients; malignant nerve sheath tumor was the main cause of death (60%).ConclusionsWe found significantly increased SMRs indicating excess mortality in NF1 patients compared to the general population. The definitive diagnosis of NF1 in all patients is a strength of our study, and the high rate of death related to malignant transformation is consistent with previous work. The retrospective design and hospital-based recruitment are limitations of our study. Mortality was significantly increased in NF1 patients aged 10 to 40 years and tended to be higher in females than in males.

Spectrum of movement disorders associated with glutaric aciduria type 1: a study of 16 patients.

Glutaric aciduria type 1 (GA1) is an autosomal recessive neurometabolic disorder due to glutaryl CoA dehydrogenase deficiency. Comprehensive descriptions of GA1‐associated movement disorders are rare. In order to refine the description of the motor phenotype, we prospectively studied 16 consecutive pediatric and adult GA1 patients, focusing on the movement disorders and their time course. In most patients, generalized dystonia, superimposed on baseline axial hypotonia, remained the predominant feature throughout the disease course. With aging, it tended to evolve from mobile to fixed dystonia and to be associated with akinetic‐rigid parkinsonism. Prominent orofacial involvement was a consistent feature in GA1 patients with movement disorders, resulting in speech disorders with features of combined hyperkinetic dysarthria and speech apraxia. The types and outcome of movement disorders in this setting should be taken into consideration during rehabilitation and for patient selection and evaluation in therapeutic trials.

Rhinoscleroma: A French National Retrospective Study of Epidemiological and Clinical Features

BACKGROUNDnRhinoscleroma (RS) is a rare, chronic, granulomatous disease of the upper respiratory tract that is associated with infection with Klebsiella rhinoscleromatis. RS is more common in certain geographic regions than in others, but other risk factors and the pathogenesis of RS remain unclear.nnnMETHODSnWe sent a standardized questionnaire to all pathologists and otolaryngology specialists in French University Hospitals and asked whether they had seen patients with RS in the previous 16 years (1990-2005). We then retrospectively reviewed the files of all patients identified.nnnRESULTSnWe collected 11 cases of RS, with a median patient age at diagnosis of 35.7 years (range, 5-72 years). The 3 patients with a familial history of RS presented with early-onset forms of RS; 1 had an uncommon aggressive presentation of the disease with ischemic stroke. Two unrelated consanguineous families were identified, 1 of which included 2 affected siblings. Two patients with sporadic disease were positive for HIV infection. All patients were living in France, but most were immigrants from areas where RS is endemic (North Africa, 3 of the 11 patients; West Africa, 4 patients; and Turkey, 1 patient). The probable duration of exposure to K. rhinoscleromatis in endemic areas varied widely: 0-28 years. Clinical features and outcome also varied considerably among cases. Biopsies had been performed for all patients and revealed granulomas containing Mikulicz cells. Cultures of biopsy tissue were positive for K. rhinoscleromatis in 5 of the 11 cases. Prolonged antibiotic treatment was administered to all patients, as follows: ciprofloxacin (7 patients), third-generation cephalosporins (2), tetracycline (2), and clofazimine (2). Eight of the 11 patients did not experience relapse during extended periods of follow-up (1.3-12 years). Relapses in 3 patients were confirmed by a second biopsy.nnnCONCLUSIONSnThe occurrence of early-onset RS in multiplex and/or consanguineous families suggests that genetic control of the host response to K. rhinoscleromatis may be involved in the pathogenesis of RS in endemic areas.

Complex alternative splicing of the myelin oligodendrocyte glycoprotein gene is unique to human and non-human primates.

Myelin/oligodendrocyte glycoprotein (MOG) is a minor integral membrane protein specific to CNS myelin, encoded by a gene located in the major histocompatibility complex. MOG is an highly encephalitogenic autoantigen and a target for autoaggressive immune responses in CNS inflammatory demyelinating diseases. We performed transcriptomic analyses for a gene expressed only in mammalian CNS, myelin oligodendrocyte glycoprotein (MOG). Complex splicing patterns were exclusively found in primates and not in mice, unlike patterns found for other myelin protein genes. In addition to those shared with rodents, these multiple MOG isoforms likely support functions unique to the primate order, in particular maintenance of myelin structure, intracellular signaling, and modulation of CNS autoimmunity via exposure of specific MOG determinants. Developmentally, in human brain the splice variants of MOG appear at a late stage compared to the major isoform, coincidental with myelination and myelin maturation, unlike other myelin proteins. These findings are discussed within the framework of a biological basis for phenotype diversity in recent mammalian evolution and for the notoriously variable clinical expression of diseases such as multiple sclerosis.

Tumor-like enlargement of the optic chiasm in an infant with Alexander disease

We report a patient with infantile Alexander disease (AXD) due to the recurrent p.Arg79Cys GFAP mutation. In addition to typical AXD abnormalities, magnetic resonance imaging demonstrated a tumor-like lesion of the optic chiasm suggestive of a glioma. A transient papilloedema appeared during the follow-up and the lesion partially regressed despite a worsening of white matter involvement. Rare radiological and pathological tumor-like lesions have already been reported in AXD patients. This patient confirms that enlargement of the optic chiasm is a rare feature of AXD, possibly linked to abnormal astrocytic proliferation.

Developmental Splicing Deregulation in Leukodystrophies Related to EIF2B Mutations

Leukodystrophies (LD) are rare inherited disorders that primarily affect the white matter (WM) of the central nervous system. The large heterogeneity of LD results from the diversity of the genetically determined defects that interfere with glial cells functions. Astrocytes have been identified as the primary target of LD with cystic myelin breakdown including those related to mutations in the ubiquitous translation initiation factor eIF2B. EIF2B is involved in global protein synthesis and its regulation under normal and stress conditions. Little is known about how eIF2B mutations have a major effect on WM. We performed a transcriptomic analysis using fibroblasts of 10 eIF2B-mutated patients with a severe phenotype and 10 age matched patients with other types of LD in comparison to control fibroblasts. ANOVA was used to identify genes that were statistically significantly differentially expressed at basal state and after ER-stress. The pattern of differentially expressed genes between basal state and ER-stress did not differ significantly among each of the three conditions. However, 70 genes were specifically differentially expressed in eIF2B-mutated fibroblasts whatever the stress conditions tested compared to controls, 96% being under-expressed. Most of these genes were involved in mRNA regulation and mitochondrial metabolism. The 13 most representative genes, including genes belonging to the Heterogeneous Nuclear Ribonucleoprotein (HNRNP) family, described as regulators of splicing events and stability of mRNA, were dysregulated during the development of eIF2B-mutated brains. HNRNPH1, F and C mRNA were over-expressed in foetus but under-expressed in children and adult brains. The abnormal regulation of HNRNP expression in the brain of eIF2B-mutated patients was concomitant with splicing dysregulation of the main genes involved in glial maturation such as PLP1 for oligodendrocytes and GFAP in astrocytes. These findings demonstrate a developmental deregulation of splicing events in glial cells that is related to abnormal production of HNRNP, in eIF2B-mutated brains.

Leukodystrophies with astrocytic dysfunction

Astrocytic dysfunctions have been recently identified in four leukosdystrophies without peripheral nervous system myelin involvement. Alexander disease, the first primary genetic astrocytic disorder identified, is due to dominant GFAP mutations. The presence of Rosenthal fibers throughout the CNS is the pathological hallmark of this disease. Neurological degradation, megalencephaly, and typical MRI pattern are characteristic of infantile sporadic patients. Nevertheless, clinical and MRI expression is large, including late onset forms which can be familial. Spongiform or cystic white matter CNS degeneration is present in the other three recessive disorders. The visualization of a white matter cystic breakdown on MRI has led to the identification of CACH/VWM and MLC diseases. CACH/VWM is due to mutations in one of the five subunits of EIF2B which compromise the astrocytic lineage. The clinical spectrum is large, from antenatal to adult forms, and several extraneurological organs can be affected. Mutations in MLC1, which is mainly expressed in astrocyte endfeet, produce megalencephaly, whereas the mild clinical course contrasts with severe MRI features. An increased concentration of NAA in the urine is sufficient to diagnose Canavan disease, which is due to mutations of the ASPA gene. These disorders highlight the role of astrocytes in myelination or myelin maintenance.

Clinical characteristics predicting internal neurofibromas in 357 children with neurofibromatosis-1: results from a cross-selectional study

ObjectiveTo identify clinical characteristics associated with internal neurofibromas in children with NF1, as a means of ensuring the early identification of patients at high risk for malignant peripheral nerve-sheath tumors developed from preexisting internal neurofibromas.Patients and methodsWe used data from two NF1 populations, in France and North America, respectively. The French database comprised 1083 patients meeting NIH diagnostic criteria for NF1 and the Neurofibromatosis Institute Database of North America comprised 703 patients. Patients younger than 17 years of age were eligible for our study if they had been evaluated for internal neurofibromas using computed tomography and/or magnetic resonance imaging. Clinical characteristics associated with internal neurofibromas by univariate analysis (Pu2009≤u20090.15) were entered into a multiple logistic regression model after checking for potential interactions and confounding. Multiple imputation was used for missing values.ResultsAmong the 746 children in the two databases, 357 (48%) met our inclusion criteria. Their mean age was 7.7u2009±u20095.0 years and there were 192 (53.8%) males. Internal neurofibromas were present in 35 (9.8%) patients. Internal neurofibromas developed earlier in females than in males and their prevalence increased during adolescence. Factors independently associated with internal neurofibromas were age (ORu2009=u20091.16 [1.07-1.27]), xanthogranulomas (ORu2009=u20095.85 [2.18-15.89]) and presence of both subcutaneous and plexiform neurofibromas (ORu2009=u20096.80 [1.52-30.44]).ConclusionsSeveral easily recognizable clinical characteristics indicate a high risk of internal neurofibromas in children with NF1 and, therefore, a need for very close monitoring.