The Incidence and Evolution of Parkinsonian Rigidity in Rett Syndrome: A Pilot Study.

BACKGROUND: Patients with Rett syndrome (RTT) may demonstrate parkinsonian features. Here, we report a preliminary cross-sectional and prospective evaluation of the evolution, regional distribution, and eventual incidence of rigid tone in a cohort of MECP2 mutation-positive patients. METHODS: In 51 participants, muscle tone rigidity in extremity regions and neck plus hypomimia were quantified using an RTT rigidity distribution (RTTRD) score with a range of 0 to 15. RTTRD scores were correlated with age, ability to walk and speak, mutation type, and, in a small subgroup (n=9), cerebrospinal fluid (CSF) homovanillic acid (HVA) and 5-hydroxyindole-acetic acid levels. RESULTS: Participant ages ranged from 2 years and 5 months, to 54 years. Rigidity was found in 43/51 (84.3%); it appeared as early as age 3, increased in extent with age, and was present in all participants aged ≥13. Ankle region rigidity appeared first, followed by proximal legs, arms, neck, and face. Ambulatory participants (n=21) had lower RTTRD scores than nonambulatory (n=30; p=0.003). We found a trend to lower scores in participants with retained speech (n=13) versus those with none (n=38; p=0.074), and no difference in scores for those with truncating (n=25) versus missense mutations (n=22; p=0.387). RTTRD scores correlated negatively with CSF HVA levels (R=-0.83; p=0.005), but not with 5-hydroxyindole-acetic acid levels (R=-0.45; p=0.22). CONCLUSIONS: Although assessment of muscle tone is somewhat subjective and the RTTRD has not been validated, this study nevertheless suggests that parkinsonian rigidity in RTT is common and frequently increases in extent with age; its severity correlates directly with impaired ambulation and inversely with CSF HVA levels.

Abnormal expression of cerebrospinal fluid cation chloride cotransporters in patients with Rett syndrome.

OBJECTIVE: Rett Syndrome is a progressive neurodevelopmental disorder caused mainly by mutations in the gene encoding methyl-CpG-binding protein 2. The relevance of MeCP2 for GABAergic function was previously documented in animal models. In these models, animals show deficits in brain-derived neurotrophic factor, which is thought to contribute to the pathogenesis of this disease. Neuronal Cation Chloride Cotransporters (CCCs) play a key role in GABAergic neuronal maturation, and brain-derived neurotrophic factor is implicated in the regulation of CCCs expression during development. Our aim was to analyse the expression of two relevant CCCs, NKCC1 and KCC2, in the cerebrospinal fluid of Rett syndrome patients and compare it with a normal control group. METHODS: The presence of bumetanide sensitive NKCC1 and KCC2 was analysed in cerebrospinal fluid samples from a control pediatric population (1 day to 14 years of life) and from Rett syndrome patients (2 to 19 years of life), by immunoblot analysis. RESULTS: Both proteins were detected in the cerebrospinal fluid and their levels are higher in the early postnatal period. However, Rett syndrome patients showed significantly reduced levels of KCC2 and KCC2/NKCC1 ratio when compared to the control group. CONCLUSIONS: Reduced KCC2/NKCC1 ratio in the cerebrospinal fluid of Rett Syndrome patients suggests a disturbed process of GABAergic neuronal maturation and open up a new therapeutic perspective.

S-adenosylmethionine and S-adenosylhomocysteine in plasma and cerebrospinal fluid in Rett syndrome and the effect of folinic acid supplementation.

Rett syndrome is a neurodevelopmental disorder characterized by cognitive and locomotor regression and stereotypic hand movements. The disorder is caused by mutations in the X chromosomal MECP2 a gene encoding methyl CpG-binding protein. It has been associated with disturbances of cerebral folate homeostasis, as well as with speculations on a compromised DNA-methylation. Folinic acid is the stable form of folate. Its derived intermediate 5-MTHF supports the conversion of homocysteine to methionine, the precursor of S-adenosylmethionine (SAM). This in turn donates its methyl group to various acceptors, including DNA, thereby being converted to S-adenosylhomocysteine (SAH). The SAM/SAH ratio reflects the methylation potential. The goal of our study was to influence DNA methylation processes and ameliorate the clinical symptoms in Rett syndrome. Therefore we examined the hypothesis that folinic acid supplementation, besides increasing cerebrospinal fluid (CSF) 5-MTHF (p = 0.003), influences SAM and SAH and their ratio. In our randomized, double-blind crossover study on folinic acid supplementation, ten female Rett patients received both folinic acid and placebo for 1 year each. It was shown that both SAM and SAH levels in the CSF remained unchanged following folinic acid administration (p = 0.202 and p = 0.097, respectively) in spite of a rise of plasma SAM and SAH (p = 0.007; p = 0.009). There was no significant change in the SAM/SAH ratio either in plasma or CSF. The apparent inability of Rett patients to upregulate SAM and SAH levels in the CSF may contribute to the biochemical anomalies of the Rett syndrome. Our studies warrant further attempts to promote DNA methylation in the true region of interest, i.e. the brain.

Folinic acid supplementation in Rett syndrome patients does not influence the course of the disease: a randomized study.

Rett syndrome is a neurodevelopmental disorder in girls, related to mutations in MECP2 gene. It has been postulated that low 5-methyltetrahydrofolate (5-MTHF) levels are present in cerebrospinal fluid. Folinic acid demonstrated clinical improvement. However, because studies have produced conflicting results, we performed a randomized, double-blind crossover, long-term, follow-up study on folinic acid. Eight Rett syndrome patients received both folinic acid and placebo, for 1 year each. Measurements included plasma folate, 5-MTHF, and clinical outcome scores like Rett Syndrome Motor Behavioral Assessment, Hand Apraxia Scale, and the parental Overall Well-Being Index. In 2 patients, low 5-MTHF levels were present. Folinic acid supplementation increased cerebrospinal fluid 5-MTHF levels, but with no objective evidence of clinical improvement. The Overall Well-Being Index showed a significant difference in favor of folinic acid, not confirmed objectively. In our double-blind randomized study, folinic acid supplementation resulted in increased 5-MTHF levels, but with no objective signs of clinical improvement.

Evaluation of CSF neurotransmitters and folate in 25 patients with Rett disorder and effects of treatment.

BACKGROUND: Rett disorder (RD) is a progressive neurodevelopmental entity caused by mutations in the MECP2 gene. It has been postulated that there are alterations in the levels of certain neurotransmitters and folate in the pathogenesis of this disease. Here we re-evaluated this hypothesis. PATIENTS AND METHODS: We evaluated CSF folate, biogenic amines and pterines in 25 RD patients. Treatment with oral folinic acid was started in those cases with low folate. Patients were clinically evaluated and videotaped up to 6 months after therapy. RESULTS: CSF folate was below the reference values in 32% of the patients. Six months after treatment no clinical improvement was observed. Three of the four patients with the R294X mutation had increased levels of a dopamine metabolite associated to a particular phenotype. Three patients had low levels of a serotonin metabolite. Two of them were treated with fluoxetine and one showed clinical improvement. No association was observed between CSF folate and these metabolites, after adjusting for the patients age and neopterin levels. CONCLUSION: Our results support that folinic acid supplementation has no significant effects on the course of the disease. We report discrete and novel neurotransmitter abnormalities that may contribute to the pathogenesis of RD highlighting the need for further studies on CSF neurotransmitters in clinically and genetically well characterized patients.

Folate receptor autoantibodies and spinal fluid 5-methyltetrahydrofolate deficiency in Rett syndrome.

Rett syndrome was associated with low cerebrospinal fluid (CSF) 5-methyltetrahydrofolate (5MTHF) in 42-50% of European patients whereas approximately 93% of the patients from North-America had a normal CSF 5MTHF status. We determined the CSF folate status in Rett patients living in North- and South-Western Europe and measured serum folate receptor (FR) autoantibodies of the blocking type to explain the reduced folate transport across the choroid plexus. Irrespective of their MECP2 genotype and despite normal plasma folate values, 14 of 33 Rett patients (42%) had low CSF folate levels. Blocking FR autoantibodies were found in 8 of the Rett patients (24%), 6 of whom had low CSF folate levels. FR autoimmunity was primarily found within the group of Rett patients with low CSF folate status with a higher incidence in North-Western Europe. In Rett patients from North-America 74 of 76 girls had higher folate values in both serum and CSF than European patients. The food folate fortification in North-America may account for the higher folate levels and may prevent CFD in these Rett patients. FR autoimmunity occurred predominantly in Rett patients from North-Western Europe and may contribute to cerebral folate deficiency (CFD).

Deep sedation with propofol in patients with Rett syndrome.

Herein we present the largest retrospective case-control series of deep sedation in patients with Rett syndrome, including discussion of the unique aspects of Rett syndrome that make these patients at high risk for sedation. Twenty-one patients with Rett syndrome and 21 control patients who received propofol for deep sedation to facilitate lumbar puncture were compared. Patients with Rett syndrome required significantly less propofol than control patients when standardized for weight and the duration of the procedure (P = .004). Seven of the 21 patients with Rett syndrome compared with none of the control patients experienced a serious adverse event, most of which were due to prolonged apnea (P = .004). All adverse events were transient, and all patients returned to their baseline after the procedure was completed. Sedation of patients with Rett syndrome is associated with a relatively high rate of complications and should not be done without appropriate personnel available who recognize the risks of sedating this unique population.

Determination of 5-methyltetrahydrofolate in cerebrospinal fluid of paediatric patients: reference values for a paediatric population.

BACKGROUND: Cerebral folate deficiency (CFD) has been described as a neurological syndrome associated with low 5-methyltetrahydrofolate (5-MTHF) values in cerebrospinal fluid (CSF) with normal folate concentrations in plasma. Our aim was to analyse CSF 5-MTHF concentrations in a paediatric control population and in patients with various neurological disorders. METHODS: We studied plasma and CSF samples from 63 paediatric controls (age range: 2 days to 18 years, average: 3.8 years) and from 165 patients (age range: 1 day to 22 years, average: 5.0 years) with severe epileptic encephalopathies of unknown origin, movement disorders, Rett syndrome and mitochondrial diseases. CSF 5-methyltetrahydrofolate was analysed by reverse phase HPLC with fluorescence detection (excitation: 295 nm and emission: 355 nm). RESULT: A negative correlation between 5-MTHF values and age of controls was observed (r=-0.468; p<0.0001) and reference values were therefore stratified into 3 age groups. Regarding patients, 122 out of 165 showed normal CSF 5-MTHF values while 43 showed decreased values ranging from profound to mild deficiencies. Increased CSF total protein values were associated with the presence of low 5-MTHF concentrations (chi(2)=7.796; p=0.005). CONCLUSIONS: The application of this method has been useful for the establishment of reference values and for diagnosis of CFD in paediatric patients. Furthermore, increased CSF total protein concentrations should be considered as a marker of a possible CFD.

Síndrome de Rett: reporte de un caso y revisión de la literatura / Rett Syndrome: Case presentation and review

El síndrome de Rett es un trastorno del neurodesarrollo caracterizado por regresión en el desarrollo psicomotor con manifestaciones autísticas, desaceleración del crecimiento de la cabeza, convulsiones, pérdidas de las funciones propositivas manuales y movimientos repetitivos esteotipados de las manos. Ocurre predominantemente en mujeres, es causado por una mutación en el gen que codifica para la proteína ligadora de metil-CpG-2(MECP-2). Presentamos el caso de una niña de 9 años de edad que era normal hasta los 6 meses, fecha a partir de la cual inicia un cuadro emético crónico, seguido tiempo después con retraso psicomotor, pérdida de las habilidades adquiridas, además de movimientos estereotipados de las manos y crisis convulsiva. El estudio de ADN para la mutación del gen de MECP-2 confirmó el diagnóstico de síndrome de Rett. La presentación y el curso de nuestra paciente deben de alertarnos sobre la posibilidad de síndrome de Rett como diagnóstico diferencial en niños hondureños con enfermedad de neurodegenerativa en los primeros dos años de vida...(AU)

Síndrome de Rett: reporte de un caso y revisión de la literatura / Rett Syndrome: Case presentation and review

El síndrome de Rett es un trastorno del neurodesarrollo caracterizado por regresión en el desarrollo psicomotor con manifestaciones autísticas, desaceleración del crecimiento de la cabeza, convulsiones, pérdidas de las funciones propositivas manuales y movimientos repetitivos esteotipados de las manos. Ocurre predominantemente en mujeres, es causado por una mutación en el gen que codifica para la proteína ligadora de metil-CpG-2(MECP-2). Presentamos el caso de una niña de 9 años de edad que era normal hasta los 6 meses, fecha a partir de la cual inicia un cuadro emético crónico, seguido tiempo después con retraso psicomotor, pérdida de las habilidades adquiridas, además de movimientos estereotipados de las manos y crisis convulsiva. El estudio de ADN para la mutación del gen de MECP-2 confirmó el diagnóstico de síndrome de Rett. La presentación y el curso de nuestra paciente deben de alertarnos sobre la posibilidad de síndrome de Rett como diagnóstico diferencial en niños hondureños con enfermedad de neurodegenerativa en los primeros dos años de vida...

Cerebrospinal fluid concentrations of folate, biogenic amines and pterins in Rett syndrome: treatment with folinic acid.

BACKGROUND: Previous studies in Rett syndrome (RS) patients suggested various abnormalities in biogenic amines, pterins, and folate values in cerebrospinal fluid (CSF). Our aim was to analyse these metabolites in CSF of 16 RS patients (age range: 2 - 23 years). Biogenic amines, pterins, and 5-methyltetrahydrofolate were measured by HPLC with electrochemical and fluorescence detection. RESULTS: CSF values of 5-methyltetrahydrofolate were decreased in 8 out of 16 RS patients (average: 53.6 nmol/L; range: 19 - 92) when compared with our reference values (average: 74.6 nmol/L; range: 45 - 127). These eight patients had epilepsy, while 4 out of 16 RS patients who did not have epilepsy showed normal CSF 5-methyltetrahydrofolate concentrations. Values of biogenic amines or pterins were decreased in four of the patients with low values of 5-methyltetrahydrofolate. No correlation was observed between CSF values of 5-methyltetrahydrofolate and pterins, biogenic amines, or age. Supplementation with folinic acid was applied in six out of the eight patients with CSF 5-methyltetrahydrofolate deficiency. An improvement was noticed in all cases. CONCLUSIONS: An important percentage of RS patients showed 5-methyltetrahydrofolate concentrations under the reference values. Therefore, analysis of CSF 5-methyltetrahydrofolate seems advisable in RS, especially in patients with epilepsy and those resistant to antiepileptic drugs.

Neurotrophic factors in the pathogenesis of Rett syndrome.

Rett syndrome is characterized by disruption of a period of vigorous brain growth with synapse development. Neurotrophic factors are important regulators of neuronal growth, differentiation, and survival during early brain development. The aims of this study were to study the role of neurotrophic factors in Rett syndrome, specifically whether Rett syndrome has abnormal levels of specific neurotrophic factors in serum and cerebrospinal fluid and whether the changes differ from other neuropediatric patients, for example, those with infantile autism. Four neurotrophic factors were measured: nerve growth factor, brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor, and insulin-like growth factor 1 from the frozen cerebrospinal fluid and from serum (except glial cell line-derived neurotrophic factor) by enzyme-linked immunosorbent assay and cerebrospinal fluid glutamate and aspartate by high-performance liquid chromatography (HPLC) method in patients with Rett syndrome. Insulin-like growth factor 1 was measured from the cerebrospinal fluid of patients with infantile autism. We found low concentrations of cerebrospinal fluid nerve growth factor in patients with Rett syndrome compared with control patients. The serum levels and other cerebrospinal fluid neurotrophic factor levels of the patients did not differ from the controls. Patients with Rett syndrome had high cerebrospinal fluid glutamate levels. Patients with infantile autism had low cerebrospinal fluid insulin-like growth factor 1 levels. Nerve growth factor acts especially on cholinergic neurons of the basal forebrain, whereas insulin-like growth factor 1 acts on cerebellar neurons. In Rett syndrome, the forebrain is more severely affected than the other cortical areas. In autism, many studies show hippocampal or cerebellar pathology. Our findings are in agreement with the different morphologic and neurochemical findings (brain growth, affected brain areas, neurotransmitter metabolism) in the two syndromes. Impairment in dendritic development in Rett syndrome could be the consequence of cholinergic deficiency and of neurotrophic factor/glutamate imbalance. Cholinergic gene expression might be influenced by the Rett syndrome gene directly or via the neurotrophic factor system.

Decreased cerebrospinal fluid levels of beta-phenylethylamine in patients with Rett syndrome.

To clarify the mechanism of brain impairment in Rett syndrome, we measured the cerebrospinal fluid levels of beta-phenylethylamine (PEA) in 17 patients with Rett syndrome. Findings were compared with those obtained in age-matched controls and diseased controls. The cerebrospinal fluid level of PEA was significantly lower in patients with Rett syndrome than in the controls (31% of control values). The alteration in the cerebrospinal fluid level of PEA may reflect dopamine system impairment in Rett syndrome.

Cerebrospinal fluid gangliosides in patients with Rett syndrome and infantile neuronal ceroid lipofuscinosis.

Concentrations of the four major brain gangliosides, GM1, GD1a, GD1b and GT1b, biochemical markers of neuronal membranes, were determined in cerebrospinal fluid from a large series of patients with classical Rett syndrome, aged 1.5-21 years at sampling, and from 11 patients with infantile neuronal ceroid lipofuscinosis, aged 1.5-11 years. The results were compared with age-matched healthy controls. Compared with fluid from the control group, the cerebrospinal fluid samples from Rett patients contained significantly reduced levels of gangliosides GD1a and GT1b. In cerebrospinal fluid of the infantile neuronal ceroid lipofuscinosis patients, even the very young ones, all four major brain gangliosides were significantly reduced compared with controls and the concentration levels also differed significantly from those in patients with Rett syndrome. The ganglioside pattern in the brain is reflected in the cerebrospinal fluid early in the course of the disease in Rett syndrome and infantile neuronal ceroid lipofuscinosis.

Developmental aspects of cerebrospinal fluid levels of beta-phenylethylamine and it's role in pediatric neurological disorders.

To clarify the role of beta-phenylethylamine (PEA) in pediatric neurological disorders, we have measured the cerebrospinal fluid (CSF) levels of PEA in 12 children with aseptic meningitis--6 were in the acute phase and the other 6 were in the recovery phase--and 5 children with Rett Syndrome (RS). The findings were compared with those obtained from 13 age-matched children with leukemia as child controls and from 10 adults patients without any neurological symptoms and signs as control. In the control group, the CSF PEA level was negatively correlated with age until 200 months (17 years) old. The mean PEA levels in meningitis and RS were significantly lower than that of child controls (p < 0.03). The alteration in the CSF levels of PEA may be related to transient changes in the dopaminergic tone in aseptic meningitis and neurological impairment, especially in the dopaminergic neurons in RS.

Levels of cerebrospinal fluid nerve-growth factor differ in infantile autism and Rett syndrome.

Autism and Rett syndrome (RS) are both developmental disorders of unknown origin. Autism is a behaviourally defined syndrome. RS, which affects girls only, is characterized by a profound learning disability following early normal development, with a consistent cluster of clinical features. Differentiation of RS from infantile autism in the very early stages of the disorders is not always easy. Both syndromes still lack discriminative laboratory markers for accurate diagnosis and differentiation. We decided to compare the CSF nerve-growth factor (NGF) levels of children with infantile autism and children with RS using enzyme-linked immunosorbent assay (ELISA). Our findings of mainly normal CSF NGF in autism and low to negligible values in RS are in agreement with the different morphological and neurochemical findings (brain growth, affected brain areas, neurotransmitter metabolism) in the two syndromes. CSF NGF could be used as a biochemical marker for differentiation of patients with autism from those with RS.

Decreased cerebrospinal fluid levels of substance P in patients with Rett syndrome.

To clarify the mechanism of brain and spinal cord impairment in Rett syndrome (RS), we measured the cerebrospinal fluid (CSF) levels of substance P in 20 patients with RS including 16 childhood patients and 4 adult patients. Findings were compared with those obtained in age-matched controls and diseased controls. The CSF level of substance P was significantly lower in patients with RS compared with controls. The alteration in the CSF level of substance P may be related to the neurological impairment, especially autonomic dysfunction, and neuropathological involvement of dorsal root ganglia and peripheral nerve observed in RS.

CSF beta-endorphin levels in patients with infantile autism.

We measured CSF levels of beta-endorphin, an opioid hormone, in 19 patients with infantile autism and in 3 patients with Rett syndrome, and compared them with control values. In infantile autism, CSF levels of beta-endorphin did not differ significantly from those of age-matched controls. There was no significant correlation between CSF levels and clinical symptoms, including self-injurious behavior, pain insensitivity, and stereotyped movement. However, CSF levels of beta-endorphin were significantly higher in the patients with Rett syndrome than in the control (p < .05). Data suggest that neurons containing beta-endorphin may not be involved in patients with infantile autism. Thus, there is no relationship between dysfunction of brain opioid and autism.

Neurobiology and neurochemistry of Rett syndrome.

Rett syndrome (RS) represents a neurodevelopmental disorder of uncertain pathogenesis, featuring an apparent arrest in neural maturation during the perinatal period. Recent findings highlight the intensive ongoing research activities surrounding the neurobiology and neurochemistry of this unique disorder. Abnormalities in multiple neurotransmitter/receptor systems (dopaminergic, glutamatergic, and cholinergic), whether primary or secondary, underscore the pervasive effects of this maturational arrest. The possible role of neurotrophic factors is supported by significantly reduced nerve growth factor levels in cerebrospinal fluid. Similarly, gangliosides and other neuronal markers are perturbed in RS and may represent another critical area of study. The availability of a suitable animal model would accelerate the pace of these important investigations.