Circulating 4-F4t-Neuroprostane and 10-F4t-Neuroprostane Are Related to MECP2 Gene Mutation and Natural History in Rett Syndrome.

Neuroprostanes, a family of non-enzymatic metabolites of the docosahexaenoic acid, have been suggested as potential biomarkers for neurological diseases. Objective biological markers are strongly needed in Rett syndrome (RTT), which is a progressive X-linked neurodevelopmental disorder that is mainly caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene with a predominant multisystemic phenotype. The aim of the study is to assess a possible association between MECP2 mutations or RTT disease progression and plasma levels of 4(RS)-4-F4t-neuroprostane (4-F4t-NeuroP) and 10(RS)-10-F4t-neuroprostane (10-F4t-NeuroP) in typical RTT patients with proven MECP2 gene mutation. Clinical severity and disease progression were assessed using the Rett clinical severity scale (RCSS) in n = 77 RTT patients. The 4-F4t-NeuroP and 10-F4t-NeuroP molecules were totally synthesized and used to identify the contents of the plasma of the patients. Neuroprostane levels were related to MECP2 mutation category (i.e., early truncating, gene deletion, late truncating, and missense), specific hotspot mutations (i.e., R106W, R133C, R168X, R255X, R270X, R294X, R306C, and T158M), and disease stage (II through IV). Circulating 4-F4t-NeuroP and 10-F4t-NeuroP were significantly related to (i) the type of MECP2 mutations where higher levels were associated to gene deletions (p ≤ 0.001); (ii) severity of common hotspot MECP2 mutation (large deletions, R168X, R255X, and R270X); (iii) disease stage, where higher concentrations were observed at stage II (p ≤ 0.002); and (iv) deficiency in walking (p ≤ 0.0003). This study indicates the biological significance of 4-F4t-NeuroP and 10-F4t-NeuroP as promising molecules to mark the disease progression and potentially gauge genotype-phenotype associations in RTT.

Oxygen exchange and energy metabolism in erythrocytes of Rett syndrome and their relationships with respiratory alterations.

Rett syndrome (RTT) is a neurodevelopmental disorder, mainly affecting females, which is associated to a mutation on the methyl-CpG-binding protein 2 gene. In the pathogenesis and progression of classic RTT, red blood cell (RBC) morphology has been shown to be an important biosensor for redox imbalance and chronic hypoxemia. Here we have evaluated the impact of oxidation and redox imbalance on several functional properties of RTT erythrocytes. In particular, we report for the first time a stopped-flow measurement of the kinetics of oxygen release by RBCs and the analysis of the intrinsic affinity of the hemoglobin (Hb). According to our experimental approach, RBCs from RTT patients do not show any intrinsic difference with respect to those from healthy controls neither in Hb's oxygen-binding affinity nor in O2 exchange processes at 37 °C. Therefore, these factors do not contribute to the observed alteration of the respiratory function in RTT patients. Moreover, the energy metabolism of RBCs, from both RTT patients and controls, was evaluated by ion-pairing HPLC method and related to the level of malondialdehyde and to the oxidative radical scavenging capacity of red cells. Results have clearly confirmed significant alterations in antioxidant defense capability, adding important informations concerning the high-energy compound levels in RBCs of RTT subjects, underlying possible correlations with inflammatory tissue alterations.

Cytokines profile and peripheral blood mononuclear cells morphology in Rett and autistic patients.

A potential role for immune dysfunction in autism spectrum disorders (ASD) has been well established. However, immunological features of Rett syndrome (RTT), a genetic neurodevelopmental disorder closely related to autism, have not been well addressed yet. By using multiplex Luminex technology, a panel of 27 cytokines and chemokines was evaluated in serum from 10 RTT patients with confirmed diagnosis of MECP2 mutation (typical RTT), 12 children affected by classic autistic disorder and 8 control subjects. The cytokine/chemokine gene expression was assessed by real time PCR on mRNA of isolated peripheral blood mononuclear cells (PBMCs). Moreover, ultrastructural analysis of PBMCs was performed using transmission electron microscopy (TEM). Significantly higher serum levels of interleukin-8 (IL-8), IL-9, IL-13 were detected in RTT compared to control subjects, and IL-15 shows a trend toward the upregulation in RTT. In addition, IL-1ß and VEGF were the only down-regulated cytokines in autistic patients with respect to RTT. No difference in cytokine/chemokine profile between autistic and control groups was detected. These data were also confirmed by ELISA real time PCR. At the ultrastructural level, the most severe morphological abnormalities were observed in mitochondria of both RTT and autistic PBMCs. In conclusion, our study shows a deregulated cytokine/chemokine profile together with morphologically altered immune cells in RTT. Such abnormalities were not quite as evident in autistic subjects. These findings indicate a possible role of immune dysfunction in RTT making the clinical features of this pathology related also to the immunology aspects, suggesting, therefore, novel possible therapeutic interventions for this disorder.

Oxidative brain damage in Mecp2-mutant murine models of Rett syndrome.

Rett syndrome (RTT) is a rare neurodevelopmental disorder affecting almost exclusively females, caused in the overwhelming majority of the cases by loss-of-function mutations in the gene encoding methyl-CpG binding protein 2 (MECP2). High circulating levels of oxidative stress (OS) markers in patients suggest the involvement of OS in the RTT pathogenesis. To investigate the occurrence of oxidative brain damage in Mecp2 mutant mouse models, several OS markers were evaluated in whole brains of Mecp2-null (pre-symptomatic, symptomatic, and rescued) and Mecp2-308 mutated (pre-symptomatic and symptomatic) mice, and compared to those of wild type littermates. Selected OS markers included non-protein-bound iron, isoprostanes (F2-isoprostanes, F4-neuroprostanes, F2-dihomo-isoprostanes) and 4-hydroxy-2-nonenal protein adducts. Our findings indicate that oxidative brain damage 1) occurs in both Mecp2-null (both -/y and stop/y) and Mecp2-308 (both 308/y males and 308/+ females) mouse models of RTT; 2) precedes the onset of symptoms in both Mecp2-null and Mecp2-308 models; and 3) is rescued by Mecp2 brain specific gene reactivation. Our data provide direct evidence of the link between Mecp2 deficiency, oxidative stress and RTT pathology, as demonstrated by the rescue of the brain oxidative homeostasis following brain-specifically Mecp2-reactivated mice. The present study indicates that oxidative brain damage is a previously unrecognized hallmark feature of murine RTT, and suggests that Mecp2 is involved in the protection of the brain from oxidative stress.

Morphological changes and oxidative damage in Rett Syndrome erythrocytes.

BACKGROUND: Hypoxemia and increased oxidative stress (OS) have been reported in Rett Syndrome (RTT), a genetical neurodevelopmental disorder. Although OS and hypoxemia can lead to red blood cells (RBCs) shape abnormalities, no information on RBCs morphology in RTT exists. Here, RBCs shape was evaluated in RTT patients and healthy subjects as a function of OS markers, blood oxygenation, pulmonary gas exchange, and cardio-respiratory parameters. METHODS: RBCs morphology was evaluated by Scanning Electron Microscopy. Intraerythrocyte and plasma non protein-bound iron (NPBI), esterified F(2)-Isoprostanes (F(2)-IsoPs), 4-HNE protein adducts (4-HNE PAs) were measured. Pulmonary oxygen gradients and PaO(2) were evaluated by gas analyzers and cardiopulmonary variables by pulse oximetry. In RTT patients these parameters were assessed before and after ω-3 polyunsaturated fatty acids (ω-3 PUFAs) administration. RESULTS: Altered RBCs shapes (leptocytes) and increased NPBI were present in RTT, together with increased erythrocyte membrane esterified F(2)-IsoPs and 4-HNE PAs. Abnormal erythrocyte shapes were related to OS markers levels, pulmonary gas exchange, PaO(2) and cardio-respiratory variables. After ω-3 PUFAs, a decrease of leptocytes was accompanied by a progressive increase in reversible forms of RBCs. This partial RBCs morphology rescue was related to decreased OS damage markers, improved pulmonary oxygen exchange, and cardiopulmonary physiology. CONCLUSIONS: These findings indicate that in RTT 1) RBCs shape is altered; 2) the OS-hypoxia diad is critical in generating altered RBCs shape and membrane damage; 3) ω-3 PUFAs are able to partially rescue RBCs morphology and the OS-derived damage. GENERAL SIGNIFICANCE: RBCs morphology is an important biosensor for OS imbalance and chronic hypoxemia.

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.

A plasma proteomic approach in Rett syndrome: classical versus preserved speech variant.

Rett syndrome (RTT) is a progressive neurodevelopmental disorder mainly caused by mutations in the gene encoding the methyl-CpG-binding protein 2 (MeCP2). Although over 200 mutations types have been identified so far, nine of which the most frequent ones. A wide phenotypical heterogeneity is a well-known feature of the disease, with different clinical presentations, including the classical form and the preserved speech variant (PSV). Aim of the study was to unveil possible relationships between plasma proteome and phenotypic expression in two cases of familial RTT represented by two pairs of sisters, harbor the same MECP2 gene mutation while being dramatically discrepant in phenotype, that is, classical RTT versus PSV. Plasma proteome was analysed by 2-DE/MALDI-TOF MS. A significant overexpression of six proteins in the classical sisters was detected as compared to the PSV siblings. A total of five out of six (i.e., 83.3%) of the overexpressed proteins were well-known acute phase response (APR) proteins, including alpha-1-microglobulin, haptoglobin, fibrinogen beta chain, alpha-1-antitrypsin, and complement C3. Therefore, the examined RTT siblings pairs proved to be an important benchmark model to test the molecular basis of phenotypical expression variability and to identify potential therapeutic targets of the disease.

Effects of ω-3 polyunsaturated fatty acids on plasma proteome in Rett syndrome.

The mechanism of action of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) is only partially known. Prior reports suggest a partial rescue of clinical symptoms and oxidative stress (OS) alterations following ω -3 PUFAs supplementation in patients with Rett syndrome (RTT), a devastating neurodevelopmental disorder with transient autistic features, affecting almost exclusively females and mainly caused by sporadic mutations in the gene encoding the methyl CpG binding protein 2 (MeCP2) protein. Here, we tested the hypothesis that ω-3 PUFAs may modify the plasma proteome profile in typical RTT patients with MECP2 mutations and classic phenotype. A total of 24 RTT girls at different clinical stages were supplemented with ω-3 PUFAs as fish oil for 12 months and compared to matched healthy controls. The expression of 16 proteins, mainly related to acute phase response (APR), was changed at the baseline in the untreated patients. Following ω-3 PUFAs supplementation, the detected APR was partially rescued, with the expression of 10 out of 16 (62%) proteins being normalized. ω-3 PUFAs have a major impact on the modulation of the APR in RTT, thus providing new insights into the role of inflammation in autistic disorders and paving the way for novel therapeutic strategies.

F2-dihomo-isoprostanes as potential early biomarkers of lipid oxidative damage in Rett syndrome.

Oxidative damage has been reported in Rett syndrome (RTT), a pervasive developmental disorder caused in up to 95% of cases by mutations in the X-linked methyl-CpG binding protein 2 gene. Herein, we have synthesized F(2)-dihomo-isoprostanes (F(2)-dihomo-IsoPs), peroxidation products from adrenic acid (22:4 n-6), a known component of myelin, and tested the potential value of F(2)-dihomo-IsoPs as a novel disease marker and its relationship with clinical presentation and disease progression. F(2)-dihomo-IsoPs were determined by gas chromatography/negative-ion chemical ionization tandem mass spectrometry. Newly synthesized F(2)-dihomo-IsoP isomers [ent-7(RS)-F(2t)-dihomo-IsoP and 17-F(2t)-dihomo-IsoP] were used as reference standards. The measured ions were the product ions at m/z 327 derived from the [M-181](-) precursor ions (m/z 597) produced from both the derivatized ent-7(RS)-F(2t)-dihomo-IsoP and 17-F(2t)-dihomo-IsoP. Average plasma F(2)-dihomo-IsoP levels in RTT were about one order of magnitude higher than those in healthy controls, being higher in typical RTT as compared with RTT variants, with a remarkable increase of about two orders of magnitude in patients at the earliest stage of the disease followed by a steady decrease during the natural clinical progression. hese data indicate for the first time that quantification of F(2)-dihomo-IsoPs in plasma represents an early marker of the disease and may provide a better understanding of the pathogenic mechanisms behind the neurological regression in patients with RTT.

A case of a Tunisian Rett patient with a novel double-mutation of the MECP2 gene.

Rett syndrome is an X-linked dominant disorder caused frequently by mutations in the methyl-CpG-binding protein 2 gene (MECP2). Rett patients present an apparently normal psychomotor development during the first 6-18 months of life. Thereafter, they show a short period of developmental stagnation followed by a rapid regression in language and motor development. The aim of this study was to perform a mutational analysis of the MECP2 gene in a classical Rett patient by sequencing the corresponding gene and modeling the found variants. The results showed the presence of a double-mutation: a new and de novo mutation c.535C>T (p.P179S) and the common c.763C>T (p.R255X) transition of the MECP2 gene. The p.P179S mutation was located in a conserved amino acid in CRIR domain (corepressor interacting region). Modeling results showed that the P179S transition could change local electrostatic properties by adding a negative charge due to serine hydroxyl group of this region of MeCP2 which may affect the function and stability of the protein. The p.R255X mutation is located in TRD-NLS domain (transcription repression domain-nuclear localization signal) of MeCP2 protein.

Restoration of motor learning in a mouse model of Rett syndrome following long-term treatment with a novel small-molecule activator of TrkB.

Reduced expression of brain-derived neurotrophic factor (BDNF) and impaired activation of the BDNF receptor, tropomyosin receptor kinase B (TrkB; also known as Ntrk2), are thought to contribute significantly to the pathophysiology of Rett syndrome (RTT), a severe neurodevelopmental disorder caused by loss-of-function mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MeCP2). Previous studies from this and other laboratories have shown that enhancing BDNF expression and/or TrkB activation in Mecp2-deficient mouse models of RTT can ameliorate or reverse abnormal neurological phenotypes that mimic human RTT symptoms. The present study reports on the preclinical efficacy of a novel, small-molecule, non-peptide TrkB partial agonist, PTX-BD4-3, in heterozygous female Mecp2 mutant mice, a well-established RTT model that recapitulates the genetic mosaicism of the human disease. PTX-BD4-3 exhibited specificity for TrkB in cell-based assays of neurotrophin receptor activation and neuronal cell survival and in in vitro receptor binding assays. PTX-BD4-3 also activated TrkB following systemic administration to wild-type and Mecp2 mutant mice and was rapidly cleared from the brain and plasma with a half-life of ∼2 h. Chronic intermittent treatment of Mecp2 mutants with a low dose of PTX-BD4-3 (5 mg/kg, intraperitoneally, once every 3 days for 8 weeks) reversed deficits in two core RTT symptom domains - respiration and motor control - and symptom rescue was maintained for at least 24 h after the last dose. Together, these data indicate that significant clinically relevant benefit can be achieved in a mouse model of RTT with a chronic intermittent, low-dose treatment paradigm targeting the neurotrophin receptor TrkB.

Long-term plasma levels of leptin and adiponectin in Rett syndrome.

OBJECTIVE: Rett syndrome is a progressive neurological disorder affecting almost exclusively females after age 6 months and characterised by acquired microcephaly, psychomotor retardation, growth failure, purposeless hand movements, autistic-like behaviour and wide-based and stiff legged gait. Leptin and adiponectin, peptides secreted by adipose tissue, are involved in the regulation of body weight and energy expenditure. DESIGN AND PATIENTS: We investigated in patients with Rett syndrome the variations of plasma leptin and adiponectin and their relation over a 2-year period. Sixteen female patients, mean age at the basal time 9.4 +/- 4.3 years, with classical Rett syndrome were enrolled. Controls were 16 healthy female subjects, mean age at the basal time 9.9 +/- 3.4 years. MEASUREMENTS: Blood samples were withdrawn in the morning at the baseline, 12 months after and 24 months after; plasma leptin and adiponectin concentrations were detected by ELISA. RESULTS: In patients, leptin concentrations significantly increased, while adiponectin concentrations significantly decreased. Both leptin and adiponectin values were significantly higher than those found in controls at each time. Leptin significantly correlated with adiponectin in patients, while there was not a significant correlation in controls. CONCLUSION: Since all patients were not obese, we might hypothesize that in Rett syndrome leptin and adiponectin might participate to clinical manifestations other than weight balance.

Brain-enriched microRNAs circulating in plasma as novel biomarkers for Rett syndrome.

Rett syndrome (RTT) is a severe neurodevelopmental disorder caused by mutations in the X-linked gene MECP2 (methyl-CpG-binding protein 2). Minimally invasive and accurate biomarkers of disease progression and treatment response could facilitate screening of therapeutic compounds in animal models, enrollment of better-defined participants into clinical trials, and treatment monitoring. In this study, we used a targeted approach based on analysis of brain-enriched microRNAs (miRNAs) circulating in plasma to identify miRNA biomarkers of RTT using Mecp2-mutant mice as a model system and human plasma samples. An "miRNA pair" approach, i.e. the ratio between two miRNAs, was used for data normalization. Specific miRNA pairs and their combinations (classifiers) analyzed in plasma differentiated wild-type from Mecp2 male and female mice with >90% accuracy. Individual miRNA pairs were more effective in distinguishing male (homozygous) animals than female (heterozygous) animals, suggesting that disease severity correlated with the levels of the miRNA biomarkers. In the human study, 30 RTT patients were compared with age-matched controls. The results of this study showed that miRNA classifiers were able to differentiate RTT patients from controls with 85-100% sensitivity. In addition, a comparison of various age groups demonstrated that the dynamics in levels of miRNAs appear to be associated with disease development (involvement of liver, muscle and lipid metabolism in the pathology). Importantly, certain miRNA biomarker pairs were common to both the animal models and human subjects, indicating the similarity between the underlying pathological processes. The data generated in this feasibility study suggest that circulating miRNAs have the potential to be developed as markers of RTT progression and treatment response. Larger clinical studies are needed to further evaluate the findings presented here.

Bone ultrasonography at phalanxes in patients with Rett syndrome: a 3-year longitudinal study.

Osteopenia is a frequent and early complication of Rett syndrome. This study aimed to evaluate the usefulness of Quantitative Ultrasonography (QUS) at phalanxes in the assessment and monitoring of bone status in Rett patients. We studied 109 girls (10.1+/-6.1 years; range 3-25 years) and 101 age-matched controls. Serum calcium (Ca), bone alkaline phosphatase (B-ALP), parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD) and QUS parameters at phalanxes by Bone Profiler-IGEA (amplitude dependent speed of sound: AD-SoS and bone transmission time: BTT) were measured. At baseline both QUS parameters and 25OHD levels were significantly lower in Rett patients than in controls. Serum 25OHD was inversely correlated with serum PTH and BTT Z-score and BTT Z-score was significantly lower (p<0.05) in the girls with a 25OHD serum levels

Rett syndrome and plasma leptin levels.

OBJECTIVE: To describe in patients with Rett syndrome (classic and preserved-speech variant) plasma leptin levels and their relationship to BMI (body mass index) and age. STUDY DESIGN: Female patients (n = 48; age range 3-20 years) affected by classic Rett syndrome were enrolled into the study. Eleven female patients, age range 3 to 20 years, with preserved-speech variant Rett syndrome were included in the study. Controls were 24 healthy female subjects, age range 3 to 20 years. Blood samples (3 mL) were withdrawn from an antecubital vein in the morning; plasma leptin concentrations were detected by enzyme-linked immunosorbent assay method. RESULTS: Patients with classic Rett syndrome and preserved-speech variant had leptin values significantly higher than controls. Leptin concentrations did not significantly differ between patients with classic Rett and preserved-speech variant. Leptin values positively correlated with age and BMI. CONCLUSIONS: Because in all patients the increased leptin concentrations were not associated to obesity, we hypothesize that in patients with Rett syndrome leptin might participate to clinical manifestations other than weight balance.

Retention of Mitochondria in Mature Human Red Blood Cells as the Result of Autophagy Impairment in Rett Syndrome.

Rett Syndrome (RTT), which affects approximately 1:10.000 live births, is a X-linked pervasive neuro-developmental disorder which is caused, in the vast majority of cases, by a sporadic mutation in the Methyl-CpG-binding protein-2 (MeCP2) gene. This is a transcriptional activator/repressor with presumed pleiotropic activities. The broad tissue expression of MeCP2 suggests that it may be involved in several metabolic pathways, but the molecular mechanisms which provoke the onset and progression of the syndrome are largely unknown. In this paper, we report that primary fibroblasts that have been isolated from RTT patients display a defective formation of autophagosomes under conditions of nutrient starvation and that the mature Red Blood Cells of some RTT patients retain mitochondria. Moreover, we provide evidence regarding the accumulation of the p62/SQSTM1 protein and ubiquitin-aggregated structures in the cerebellum of Mecp2 knockout mouse model (Mecp2 -/y ) during transition from the non-symptomatic to the symptomatic stage of the disease. Hence, we propose that a defective autophagy could be involved in the RTT clinical phenotype, which introduces new molecular perspectives in the pathogenesis of the syndrome.

IgA antibodies in Rett syndrome.

The level of IgA antibodies to gluten and gliadin proteins found in grains and to casein found in milk, as well as the level of IgG to gluten and gliadin, have been examined in 23 girls with Rett syndrome and 53 controls. Highly statistically significant increases were found for the Rett population compared to the controls. The reason for this remains unknown, but because IgA antibodies reflect the uptake of proteins and/or epitopes of proteins from the gut, this may be indicative of increased protein uptake.

Magnesium profile in autism.

The aim of the present study was to determine and compare plasma and erythrocyte concentrations of magnesium in 12 autistic children (10 boys, 2 girls), 17 children with other autistic spectrum disorders (14 boys, 3 girls), 5 girls with classic Rett syndrome, and 14 normal children (7 boys, 7 girls) of the same age. No differences in intracellular Mg were found between controls and pathological subjects; however, autistic children and children with other autistic spectrum disorders had significantly lower plasma concentrations of Mg than normal subjects (p=0.013 and p=0.02, respectively). Although our study population was small, we conclude that children with autistic spectrum disorders require special dietary management. If these cases are diagnosed at an early stage, they can be helped through diet.

Genotype-phenotype relationship among Egyptian children with Rett syndrome.

BACKGROUND: Rett syndrome (RTT) is an X-linked dominant neurodegenerative disorder with various MECP2 mutations. RTT is one of the most common causes of severe intellectual and complex disability in girls. Therefore, the aims of the study were as follows: to highlight the clinical manifestations of RTT; to present the genotype-phenotype relationship; and to assess the possible relation between severity score, clinical manifestations, and MECP2 gene mutations. PATIENTS AND METHODS: The present cross-sectional study included 15 girls with typical RTT, diagnosed according to the international criteria of RTT. All included patients were followed up at the pediatric neurology clinic, Cairo University Specialized Pediatric Hospital. They were subjected to screening of the entire coding region of the MECP2 gene (MECP2A and MECP2B) using denaturing high-performance liquid chromatography. The clinical severity was assessed among RTT cases using the International Scoring System. RESULTS: Stereotypic hand movements were present in all cases, acquired microcephaly was present in 73.3% of cases, autistic features in 66.7% of cases, recurrent seizures in 53.3% of cases, delayed language development in 46.6% of cases, deterioration of speech in 53.3% of cases, and growth retardation and peripheral vasomotor changes in 46.6% of cases. Positive mutations were detected in 10 cases (66.66%): heterozygous for p.R270X mutation (three cases), heterozygous for p.R255X mutation (three cases), and heterozygous for p.R168X nonsense mutation (four cases). Microcephaly, seizures, growth retardation, and autistic features were more frequent in patients with a mutated gene; it was also observed that walking ability was more frequent in patients without a mutation.; thus, genotype-phenotype relationship was confirmed. The relationship between severity score and MECP2 mutation was detected in three cases with severe RTT, but there was no relationship between the severity score and specific MECP2 mutation. There was a relationship between the severity score and the clinical manifestations of RTT. CONCLUSION: Mutations of MECP2 analysis were detected in 66.7% of RTT cases. There were relationships between the severity score, clinical manifestations, and MECP2 gene mutations. However, there was no relationship between the severity score and specific MECP2 gene mutation.

Thyroid function in Rett syndrome.

INTRODUCTION: Thyroid function in Rett syndrome (RTT) has rarely been studied with unanimous results. However, this aspect is of great concern regarding the effect thyroid hormones (TH) have on proper mammalian brain development. OBJECTIVE: To evaluate the prevalence of abnormalities of thyroid function in a cohort of children with RTT. PATIENTS AND METHODS: Forty-five consecutive Caucasian girls (mean age: 8.6 ± 5.3 years, range: 2.0-26.1) meeting the clinical criteria for RTT were recruited. In all of the subjects, we evaluated the serum concentrations of free-T3 (FT3), free-T4 (FT4), thyroid-stimulating hormone (TSH), thyroperoxidase autoantibodies, thyroglobulin autoantibodies (TgA), and TSH receptor (TSHr) autoantibodies. The results were compared with a group of 146 age-matched healthy Caucasian children and adolescent girls (median age: 9.5 years, range: 1.8-14.6) from the same geographical area. RESULTS: Mean FT3 and TSH levels were not significantly different between the RTT patients and controls. Nevertheless, FT4 levels were significantly higher in RTT patients than in controls (p < 0.005). In particular, 17.7% showed FT4 levels higher than the upper reference limit (vs. 0.7% of controls, p < 0.0001), whereas 12 patients (26.7%) showed higher FT3 levels than the upper reference limit, significantly differing in respect to controls (2.0%, p < 0.0001). Finally, 5 patients (11.1%) showed higher levels of TSH, statistically differing from the control subjects (2.0%, p < 0.0001). However, evaluating the patients on the basis of different RTT genotype subgroups, patients with CDKL5 deletions showed significantly higher FT4 values than patients with MeCP2 deletions (p < 0.05). On the other hand, patients with other types of MeCP2 mutations also showed FT4 levels significantly higher than patients with MeCP2 deletions (p < 0.05). In fact, out of 8 patients with FT4 levels higher than the upper references limit, 3 of them presented with CDKL5 deletions (3 patients, 37.5%), 4 (50%) had MeCP2 mutations, and 1 (12.5%) belonged to the subgroup of MeCP2 deletions. However, when analyzing FT3 levels of the 12 patients showing higher FT3 levels than the upper references limit, 6 (50%) belonged to the subgroup with MeCP2 mutations, 4 (33.3%) to the subgroup with MeCP2 deletions, and 2 (16.7%) to the subgroups with CDKL5 deletions. Furthermore, no patient with RTT was positive for antithyroglobulin autoantibodies, antithyroid peroxidase, or anti-TSHr, with no statistical differences in respect to the controls. L-thyroxine treatment was not necessary for any patient. CONCLUSIONS: Abnormalities of thyroid function are not rare in RTT. The possible relationship between these disorders and the RTT phenotype should be confirmed and studied. Children with RTT should be screened for potential thyroid dysfunction.