Widespread non-central nervous system organ pathology in fragile X premutation carriers with fragile X-associated tremor/ataxia syndrome and CGG knock-in mice.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder generally presenting with intention tremor and gait ataxia, but with a growing list of co-morbid medical conditions including hypothyroidism, hypertension, peripheral neuropathy, and cognitive decline. The pathological hallmark of FXTAS is the presence of intranuclear inclusions in both neurons and astroglia. However, it is unknown to what extent such inclusions are present outside the central nervous system (CNS). To address this issue, we surveyed non-CNS organs in ten human cases with FXTAS and in a CGG repeat knock-in (CGG KI) mouse model known to possess neuronal and astroglial inclusions. We find inclusions in multiple tissues from FXTAS cases and CGG KI mice, including pancreas, thyroid, adrenal gland, gastrointestinal, pituitary gland, pineal gland, heart, and mitral valve, as well as throughout the associated autonomic ganglia. Inclusions were observed in the testes, epididymis, and kidney of FXTAS cases, but were not observed in mice. These observations demonstrate extensive involvement of the peripheral nervous system and systemic organs. The finding of intranuclear inclusions in non-CNS somatic organ systems, throughout the PNS, and in the enteric nervous system of both FXTAS cases as well as CGG KI mice suggests that these tissues may serve as potential sites to evaluate early intervention strategies or be used as diagnostic factors.

Neural progenitor cells from an adult patient with fragile X syndrome.

BACKGROUND: Currently, there is no adequate animal model to study the detailed molecular biochemistry of fragile X syndrome, the leading heritable form of mental impairment. In this study, we sought to establish the use of immature neural cells derived from adult tissues as a novel model of fragile X syndrome that could be used to more fully understand the pathology of this neurogenetic disease. METHODS: By modifying published methods for the harvest of neural progenitor cells from the post-mortem human brain, neural cells were successfully harvested and grown from post-mortem brain tissue of a 25-year-old adult male with fragile X syndrome, and from brain tissue of a patient with no neurological disease. RESULTS: The cultured fragile X cells displayed many of the characteristics of neural progenitor cells, including nestin and CD133 expression, as well as the biochemical hallmarks of fragile X syndrome, including CGG repeat expansion and a lack of FMRP expression. CONCLUSION: The successful production of neural cells from an individual with fragile X syndrome opens a new avenue for the scientific study of the molecular basis of this disorder, as well as an approach for studying the efficacy of new therapeutic agents.

GRAND ROUNDS: an atypical progressive dementia in a male carrier of the fragile X premutation: an example of fragile X-associated tremor/ataxia syndrome.

This case study describes a 65-year-old man initially diagnosed with an atypical rapidly progressive dementia who subsequently participated in a research project at the MIND Institute at the University of California-Davis, where he was diagnosed with a recently identified neurodegenerative syndrome, fragile X-associated tremor/ataxia syndrome (FXTAS). He was a carrier of the fragile X premutation and in later life developed tremor, gait ataxia, parkinsonism, and cognitive deficits that progressed very rapidly. This case study provides a detailed description of the individual's history, presenting symptoms, neuropsychological test results, and postmortem neuropathological analysis. Pathological findings showed diagnostic features of both FXTAS and Alzheimer's disease, which might help to explain the rapid progression of his dementia.

Fragile X premutation carriers: characteristic MR imaging findings of adult male patients with progressive cerebellar and cognitive dysfunction.

BACKGROUND AND PURPOSE: Our purpose was to characterize the findings of MR imaging of the brain of adult male fragile X premutation carriers with a recently identified disorder characterized by ataxia, tremor, rigidity, and cognitive dysfunction. METHODS: MR imaging studies of the brain of 17 male patients were characterized for signal intensity and for size of ventricles, cerebral and cerebellar sulci, and brain stem. Comparison was made with age- and sex-matched control participants. Southern blot and/or polymerase chain reaction methods were used to analyze CGG trinucleotide repeats in the fragile X mental retardation 1 gene. RESULTS: Fifteen of 17 patients showed symmetrically decreased T1 and increased T2 signal intensity in cerebellar white matter lateral, superior, and inferior to the dentate nuclei. Fourteen of 17 had similar signal intensity alterations in the middle cerebellar peduncles. Cerebellar cortical atrophy was present in 16 of 17 and cerebral atrophy in 17 of 17. Evan's Index as a measure of ventricular size averaged 0.35 (range, 0.25-0.46), with that for age-matched control participants averaging 0.28 (range, 0.24-0.31) (P <.005). The mean third ventricle width was 11 mm (for control participants, 6 mm; P <.01). Corpus callosum was thinned in 14 of 16 participants. Middle cerebellar peduncles were atrophic when compared with those of control participants (P <.005). Pontine transverse dimension was 25 mm (for control participants, 31 mm; P <.005), and rostral-caudal length averaged 26 mm (for control participants, 29 mm; P <.005). CGG repeats clustered in the low to mid premutation range (86 +/- 10 CGG repeats) in the 17 patients. CONCLUSION: MR imaging findings in symptomatic male fragile X premutation carriers are characteristic of this disorder. Recognition of these alterations may support a specific diagnosis and may have implications for the potential occurrence of fragile X syndrome in the children of reproductive age female relatives.

Penetrance of the fragile X-associated tremor/ataxia syndrome in a premutation carrier population.

CONTEXT: Premutation expansions (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene are frequent in the general population, with estimated prevalences of 1 per 259 females and 1 per 813 males. Several articles have recently described the presence of late-onset neurological symptoms in male carriers of premutation (FMR1) alleles. The main clinical features described in this newly identified syndrome are cerebellar ataxia and intention tremor. Additional documented symptoms include short-term memory loss, executive functional deficits, cognitive decline, parkinsonism, peripheral neuropathy, lower-limb proximal muscle weakness, and autonomic dysfunction. OBJECTIVE: To study the penetrance of the fragile X-associated tremor/ataxia syndrome (FXTAS) among premutation carriers. DESIGN, SETTING, AND PARTICIPANTS: Family-based study of 192 individuals (premutation carriers and controls) whose families belong to the Northern or Southern California Fragile X Associations. Data were collected (March 2002-April 2003) through a survey and a standardized neurological examination, which was videotaped and subsequently scored in a blinded fashion. MAIN OUTCOME MEASURES: Penetrance of intention tremor and ataxia among adult carriers (aged > or =50 years) of premutation expansions of the FMR1 gene. RESULTS: Data from the survey of 192 individuals demonstrated an age-related penetrance of the combination of reported intention tremor and gait ataxia in male carriers (17%, 38%, 47%, and 75% [lower-bound estimates] for participants aged 50-59, 60-69, 70-79, and > or =80 years, respectively). The male carrier group had an age-adjusted 13-fold increased risk (95% confidence interval, 3.9-25.4; P =.003) of combined intention tremor and gait ataxia when compared with male controls. The clinical examination data from 93 individuals demonstrated that male carriers experienced more difficulties on each of 3 standardized neurological rating scales compared with controls (P<.05). Female carrier scores were also higher than those of female controls (P<.05) on 2 of the 3 neurological rating scales, but no participant was identified with probable or definite FXTAS. CONCLUSIONS: The study demonstrates that older male carriers of premutation alleles of the FMR1 gene are at high risk of developing FXTAS. Since male premutation carriers are relatively common in the general population, older men with ataxia and intention tremor should be screened for the FMR1 mutation, especially if these signs are accompanied by parkinsonism, autonomic dysfunction, or cognitive decline, regardless of family history.

Intranuclear inclusions in a fragile X mosaic male.

Lack of the fragile X mental retardation protein leads to Fragile X syndrome (FXS) while increased levels of FMR1 mRNA, as those observed in premutation carriers can lead to Fragile X- associated tremor ataxia syndrome (FXTAS). Until recently, FXTAS had been observed only in carriers of an FMR1 premutation (55-200 CGG repeats); however the disorder has now been described in individuals carriers of an intermediate allele (45-54 CGG repeats) as well as in a subject with a full mutation with mosaicism.Here, we report on molecular and clinical data of a male FMR1 mosaic individual with full and premutation alleles. Molecular analysis of FMR1 and FMRP expression in this subject is consistent with a FXS phenotype. We observed reduced expression of FMRP in both peripheral blood and brain leading to the FXS diagnosis. In addition, a dramatic 90% depletion of both FMR1 mRNA and FMRP levels was observed in the blood, as normally observed in FXS cases, and an even greater depletion in the brain. A clinical report of this patient, at age 71, described neurodegenerative signs of parkinsonism that were likely, in retrospect, part of a FXTAS scenario as post-mortem examination shows the presence of intranuclear inclusions, the hallmark pathology of FXTAS.The findings presented in this study indicate co-morbidity for both FXS and FXTAS in this individual carrying both full and premutation FMR1 alleles. In addition, based on symptoms and pathological and molecular evidence, this report suggests the need to redefine the diagnostic criteria of FXTAS.

Distribution and frequency of intranuclear inclusions in female CGG KI mice modeling the fragile X premutation.

The fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder caused by CGG trinucleotide repeat expansions in the fragile X mental retardation 1 (FMR1) gene. The neuropathological hallmark of FXTAS is the presence of ubiquitin-positive intranuclear inclusions in neurons and in astroglia. Intranuclear inclusions have also been reported in the neurons of male CGG KI mice carrying an expanded CGG trinucleotide repeat and used to model FXTAS, but no study has been carried out quantifying inclusions in female CGG KI mice heterozygous for the fragile X premutation. We used histologic and immunocytochemical methods to determine the pathological features of intranuclear inclusions in astroglia and neurons. In female CGG KI mice, ubiquitin-positive intranuclear inclusions were found in neurons and astroglia throughout the brain in cortical and subcortical regions. These inclusions increased in number and became larger with advanced age and increasing CGG repeat length, supporting hypotheses that these pathologic features are progressive across the lifespan. The number of inclusions in neurons was reduced by ∼25% in female CGG KI mice compared to male CGG KI mice, but not so low as the 50% predicted. These data emphasize the need to evaluate the neurocognitive and pathological features in female carriers of the fragile X premutation with and without FXTAS symptomatology is warranted, as this population shows similar neuropathological features present in male FXTAS patients.

Rare intranuclear inclusions in the brains of 3 older adult males with fragile x syndrome: implications for the spectrum of fragile x-associated disorders.

The FMR1 gene is polymorphic for the length of CGG trinucleotide repeat expansions in the 5' untranslated region. Premutation (55-200 CGG repeats) and full-mutation (>200 CGG repeats) alleles give rise to their respective disorders by different pathogenic mechanisms: RNA gain-of-function toxicity leads to fragile X-associated tremor/ataxia syndrome in the premutation range, and transcriptional silencing and absence of fragile X mental retardation protein (FMRP) lead to fragile X syndrome in the full-mutation range. However, for the latter, incomplete silencing and/or size-mosaicism might result in some contribution to the disease process from residual messenger RNA production. To address this possibility, we examined the brains of 3 cases of fragile X syndrome for the presence of intranuclear inclusions in the hippocampal dentate gyrus. We identified low levels (0.1%-1.3%) of intranuclear inclusions in all 3 cases. Quantitative reverse transcription-polymerase chain reaction for FMR1 messenger RNA and immunofluorescence for FMRP revealed low but detectable levels of both RNA and protein in the 3 cases, consistent with the presence of small numbers of inclusions. The intranuclear inclusions were only present in FMRP-immunoreactive cells. The small numbers of inclusions and very low levels of both FMR1 RNA and protein suggest that the clinical course in these 3 subjects would not have been influenced by contributions from RNA toxicity.

Neuropathologic features in the hippocampus and cerebellum of three older men with fragile X syndrome.

BACKGROUND: Fragile X syndrome (FXS) is the most common inherited form of intellectual disability, and is the most common single-gene disorder known to be associated with autism. Despite recent advances in functional neuroimaging and our understanding of the molecular pathogenesis, only limited neuropathologic information on FXS is available. METHODS: Neuropathologic examinations were performed on post-mortem brain tissue from three older men (aged 57, 64 and 78 years) who had received a clinical or genetic diagnosis of FXS. In each case, physical and cognitive features were typical of FXS, and one man was also diagnosed with autism. Guided by reports of clinical and neuroimaging abnormalities of the limbic system and cerebellum of individuals with FXS, the current analysis focused on neuropathologic features present in the hippocampus and the cerebellar vermis. RESULTS: Histologic and immunologic staining revealed abnormalities in both the hippocampus and cerebellar vermis. Focal thickening of hippocampal CA1 and irregularities in the appearance of the dentate gyrus were identified. All lobules of the cerebellar vermis and the lateral cortex of the posterior lobe of the cerebellum had decreased numbers of Purkinje cells, which were occasionally misplaced, and often lacked proper orientation. There were mild, albeit excessive, undulations of the internal granular cell layer, with patchy foliar white matter axonal and astrocytic abnormalities. Quantitative analysis documented panfoliar atrophy of both the anterior and posterior lobes of the vermis, with preferential atrophy of the posterior lobule (VI to VII) compared with age-matched normal controls. CONCLUSIONS: Significant morphologic changes in the hippocampus and cerebellum in three adult men with FXS were identified. This pattern of pathologic features supports the idea that primary defects in neuronal migration, neurogenesis and aging may underlie the neuropathology reported in FXS.

Ubiquitin-positive intranuclear inclusions in neuronal and glial cells in a mouse model of the fragile X premutation.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder caused by CGG trinucleotide repeat expansions in the fragile X mental retardation 1 (FMR1) gene. The neuropathological hallmark of the disease is the presence of ubiquitin-positive intranuclear inclusions in neurons and in astrocytes. Ubiquitin-positive intranuclear inclusions have also been found in the neurons of transgenic mice model carrying an expanded CGG((98)) trinucleotide repeat of human origin but have not previously been described in glial cells. Therefore, we used immunocytochemical methods to determine the pathological features of nuclear and/or cytoplasmic inclusions in astrocytes, Bergmann glia, and neurons, as well as relationships between inclusion patterns, age, and repeat length in CGG knock-in (KI) mice in comparison with wild-type mice. In CGG KI mice, ubiquitin-positive intranuclear inclusions were found in neurons (e.g., pyramidal cells, GABAergic neurons) throughout the brain in cortical and subcortical brain regions; these inclusions increased in number and size with advanced age. Ubiquitin-positive intranuclear inclusions were also present in protoplasmic astrocytes, including Bergmann glia in the cerebellum. The morphology of intranuclear inclusions in CGG KI mice was compared to that of typical inclusions in human neurons and astrocytes in postmortem FXTAS brain tissue. This new finding of previously unreported pathology in astrocytes of CGG KI mice now provides an important mouse model to study astrocyte pathology in human FXTAS.

Giant intracranial medullary thyroid carcinoma metastasis presenting as apoplexy.

We present a case of a giant sellar and suprasellar skull base-invasive metastasis from a medullary carcinoma of the thyroid gland. Radiographic features were similar to atypical/malignant meningioma or pituitary macroadenoma. Intracranial metastases from medullary thyroid carcinoma are very rare. Unusual features of our case are discussed.

Clinical and neuropathologic findings in a woman with the FMR1 premutation and multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) and fragile X-associated tremor/ataxia syndrome (FXTAS) have overlapping clinical signs and symptoms. OBJECTIVES: To present a case with evidence of both MS and FXTAS and to discuss the relationship of both disorders. DESIGN: Case report. SETTING: Fragile X Research and Treatment Center at the University of California, Davis, Medical Center. Patient Woman with the FMR1 premutation who died of MS at the age of 52 years. MAIN OUTCOME MEASURES: Magnetic resonance imaging, physical examination, and neuropathologic examination results. RESULTS: Magnetic resonance imaging, physical examination, and autopsy neuropathologic examination revealed diagnostic features of MS and FXTAS. CONCLUSION: The molecular mechanism of RNA toxicity, including the elevation of alphaB-crystallin levels observed in FXTAS, may lead to enhanced predisposition to autoimmune diseases.

Organotypic distribution of stem cell markers in formalin-fixed brain harboring glioblastoma multiforme.

The role of stem cells in the origin, growth patterns, and infiltration of glioblastoma multiforme is a subject of intense investigation. One possibility is that glioblastoma may arise from transformed stem cells in the ventricular zone. To explore this hypothesis, we examined the distribution of two stem cell markers, activating transcription factor 5 (ATF5) and CD133, in an autopsy brain specimen from an individual with glioblastoma multiforme. A 41-year-old male with a right posterior temporal glioblastoma had undergone surgery, radiation, and chemotherapy. The brain was harvested within several hours after death. After formalin fixation, sectioning, and mapping of tumor location in the gross specimen, histologic specimens were prepared from tumor-bearing and grossly normal hemispheres. Fluorescence immunohistochemistry and colorimetric staining were performed for ATF5 and CD133. Both markers co-localized to the ependymal and subependymal zones on the side of the tumor, but not in the normal hemisphere or more rostrally in the affected hemisphere. ATF5 staining was especially robust within the diseased hemisphere in histologically normal ependyma. To our knowledge, this is the first in situ demonstration of stem cell markers in whole human brain. These preliminary results support the hypothesis that some glioblastomas may arise from the neurogenic zone of the lateral ventricle. The robust staining for ATF5 and CD133 in histologically normal ventricular zone suggests that an increase in periventricular stem cell activity occurred in this patient on the side of the tumor, either as a localized response to brain injury or as an integral component of oncogenesis and tumor recurrence.

Testicular and pituitary inclusion formation in fragile X associated tremor/ataxia syndrome.

PURPOSE: We describe the medical course, neuropathology and testicular pathology in 2 men who died with fragile X associated tremor/ataxia syndrome. Fragile X associated tremor/ataxia syndrome, which is a recently described, late onset neurodegenerative disorder, affects up to a third of males and occasionally females older than age 50 years who are carriers of premutation alleles (55 to 200 CGG repeats) of the fragile X mental retardation 1 gene FMR1. Clinical manifestations of premutation status are distinct from those of the full mutation, which is the cause of the fragile X syndrome. MATERIALS AND METHODS: Standard pathological techniques were used to examine the brain, pituitary gland and testicular tissues of 2 males who had fragile X associated tremor/ataxia syndrome. RESULTS: The clinical course of the 2 cases included impotence before the onset of neurological symptoms of tremor and ataxia. Neuropathological findings included eosinophilic intranuclear inclusions in neurons and astrocytes throughout the central nervous system, and in the anterior and posterior pituitary gland of 1 of the 2 men. Inclusions were also seen in the Leydig and myoid cells in the testicles of these 2 men with fragile X associated tremor/ataxia syndrome. CONCLUSIONS: Fragile X associated tremor/ataxia syndrome inclusions are formed in tissues outside of the central nervous system. Involvement of the testicles and the pituitary gland may lead to neuroendocrine dysfunction, including testosterone deficiency. These noncentral nervous system components of fragile X associated tremor/ataxia syndrome require further study.

Progression of tremor and ataxia in male carriers of the FMR1 premutation.

Premutation alleles of the fragile X mental retardation 1 (FMR1) gene give rise to a late-onset movement disorder, fragile X-associated tremor/ataxia syndrome (FXTAS), characterized by progressive intention tremor and gait ataxia, with associated dementia and global brain atrophy. The natural history of FXTAS is largely unknown. To address this issue, a family-based, retrospective, longitudinal study was conducted with a cohort of 55 male premutation carriers. Analysis of the progression of the major motor signs of FXTAS, tremor and ataxia, shows that tremor usually occurs first, with median onset at approximately 60 years of age. From the onset of the initial motor sign, median delay of onset of ataxia was 2 years; onset of falls, 6 years; dependence on a walking aid, 15 years; and death, 21 years. Preliminary data on life expectancy are variable, with a range from 5 to 25 years.

Cognitive impairment in a 65-year-old male with the fragile X-associated tremor-ataxia syndrome (FXTAS).

OBJECTIVE: This is the first case report of a comprehensive neuropsychologic examination of an older man with the fragile X-associated tremor-ataxia syndrome (FXTAS). BACKGROUND: FXTAS, a newly identified phenotype affecting older male carriers of the fragile X premutation allele, is a progressive disorder marked by gait ataxia, action tremor, peripheral neuropathy, executive cognitive deficits, generalized brain atrophy, and neuronal and astrocytic intranuclear inclusion bodies throughout the brain. The patient previously had undergone neurologic evaluation, molecular analysis, and magnetic resonance imaging. METHOD: The patient was administered a neuropsychologic examination, assessing motor and somatosensory functioning, visual and spatial functioning, speech and language, attention, executive abilities, learning and memory, and reasoning. RESULTS: The patient showed a pattern of cognitive impairment characterized by essentially normal speech and language, moderately impaired control of attention, and moderate to severe deficits in working memory, executive functioning, and both declarative and procedural learning. Visual and spatial abilities were relatively unimpaired, and verbal reasoning was only mildly deficient. CONCLUSIONS: The findings suggest that a cognitive disorder, with especially marked executive cognitive function and memory deficits, accompanies FXTAS. The findings in FXTAS are compared with those in several other neurodegenerative disorders.

Paraneoplastic limbic encephalitis in a teenage girl with an immature ovarian teratoma.

Paraneoplastic limbic encephalitis (PLE) is an unusual disorder that is characterized by the association of clinical limbic system abnormalities with neoplasia, usually malignancy. It has rarely been reported in children and then manifests during the teenage years. Diagnosis is often delayed, especially when the tumor has not been recognized. In adults, the diagnosis can be revealed by the presence of antineuronal antibodies. We describe an unusual case of behavioral disturbance leading rapidly to coma in a 14-year-old girl with CSF pleocytosis who was found 10 weeks later to have an immature ovarian teratoma. Although her symptoms eventually improved slightly after tumor excision, she died while in rehabilitation. PLE is an important diagnosis to consider in the teenage girl with symptoms of a progressive limbic disorder and CSF pleocytosis, and whose brain MR imaging demonstrates no abnormality or mild T2-weighted temporal lobe signal abnormality. When this constellation of findings presents in a teenage girl, the possibility of an underlying ovarian teratoma should be considered.