Use of the ketogenic diet to manage refractory epilepsy in CDKL5 disorder: Experience of >100 patients.

OBJECTIVE: Pathogenic variants involving the CDKL5 gene result in a severe epileptic encephalopathy, often later presenting with features similar to Rett syndrome. Cardinal features of epilepsy in the CDKL5 disorder include early onset at a median age of 6 weeks and poor response to antiepileptic drugs. The ketogenic diet (KD) was first introduced in the 1920s as a treatment option for refractory epilepsy in children. This study investigated use of the KD in the CDKL5 disorder and its influences on seizures. METHODS: The International CDKL5 Disorder Database, established in 2012, collects information on individuals with the CDKL5 disorder. Families have provided information regarding seizure characteristics, use, and side effects of the KD treatment. Descriptive statistics and time to event analyses were performed. Clinical vignettes were also provided on patients attending Boston Children's Hospital. RESULTS: Data regarding KD use were available for 204 individuals with a pathogenic CDKL5 variant. Median age of inclusion in the database was 4.8 years (range = 0.3-33.9 years), with median age of 6 weeks (range = 1 day-65 weeks) at seizure onset. History of KD use was reported for 51% (104 of 204) of individuals, with a median duration of use of 17 months (95% confidence interval = 9-24). Changes in seizure activity after commencing KD were reported for two-thirds (69 of 104), with improvements in 88% (61 of 69). Nearly one-third (31.7%) experienced side effects during the diet. At ascertainment, only one-third (32%) remained on the diet, with lack of long-term efficacy as the main reason for diet cessation (51%, 36 of 70). SIGNIFICANCE: Benefits of KD in the CDKL5 disorder are in keeping with previous trials on refractory epilepsies. However, poor long-term efficacy remains as a significant barrier. In view of its side effect profile, KD administration should be supervised by a pediatric neurologist and specialist dietician.

Assessment and management of nutrition and growth in Rett syndrome.

OBJECTIVES: We developed recommendations for the clinical management of poor growth and weight gain in Rett syndrome through evidence review and the consensus of an expert panel of clinicians. METHODS: Initial draft recommendations were created based upon literature review and 34 open-ended questions in which the literature was lacking. Statements and questions were made available to an international, multidisciplinary panel of clinicians in an online format and a Microsoft Word-formatted version of the draft via e-mail. Input was sought using a 2-stage modified Delphi process to reach consensus. Items included clinical assessment of growth, anthropometry, feeding difficulties and management to increase energy intake, decrease feeding difficulties, and consideration of gastrostomy. RESULTS: Agreement was achieved on 101 of 112 statements. A comprehensive approach to the management of poor growth in Rett syndrome is recommended that takes into account factors such as feeding difficulties and nutritional needs. A body mass index of approximately the 25th centile can be considered as a reasonable target in clinical practice. Gastrostomy is indicated for extremely poor growth, if there is risk of aspiration and if feeding times are prolonged. CONCLUSIONS: These evidence- and consensus-based recommendations have the potential to improve care of nutrition and growth in a rare condition and stimulate research to improve the present limited evidence base.

Nutritional factors in a mouse model of Rett syndrome.

Environmental factors such as nutrition and housing can influence behavioral and anatomical characteristics of several neurological disorders, including Rett syndrome (RTT). RTT is associated with mutations in the X-linked gene encoding MeCP2, a transcriptional repressor that binds methylated DNA. While direct genetic intervention in humans is impossible at this time, motor and cognitive deficits in RTT may be ameliorated through manipulations of epigenetic/environmental factors. For example, studies in rodents suggest that choline nutrient supplementation during critical periods of brain development enhances cholinergic neurotransmission, alters neuronal size and distribution, and facilitates performance of memory and motoric tasks. Recent work in a mouse model of RTT shows that enhancing maternal nutrition through choline supplementation improves both anatomical and behavioral symptoms in the mutant offspring. We describe here cellular and molecular mechanisms that may underlie this specific enhancement and may provide more general insights into mechanisms underlying gene-environment interactions in neurological disorders.

Neurochemical changes in a mouse model of Rett syndrome: changes over time and in response to perinatal choline nutritional supplementation.

Rett syndrome (RTT), the second leading cause of mental retardation in girls, is caused by mutations in the X-linked gene for methyl-CpG-binding protein 2 (MeCP2), a transcriptional repressor. In addition to well-documented neuroanatomical and behavioral deficits, RTT is characterized by reduced markers of cholinergic activity and general neuronal health. Previously, we have shown that early postnatal choline (Cho) supplementation improves behavioral and neuroanatomical symptoms in a mouse model of RTT (Mecp2(1lox) mice). In this study, we use NMR spectroscopy to quantify the relative amounts of Cho, Glutamate (Glu), Glutamine (Gln), and N-acetyl aspartate (NAA) in the brains of wild type and mutant mice at 21, 35, and 42 days of age and in mice receiving postnatal Cho supplementation. We find that the mutant mice have reduced levels of Cho, Glu, and NAA, but elevated Gln levels, compared with their wild type littermates. These differences emerge at different developmental ages. Cho supplementation increases NAA levels, a marker of neuronal integrity, but has no effect on Cho, Glu, or Gln. These data suggest that postnatal nutritional supplementation may improve neuronal function and could serve as a therapeutic agent for human RTT patients.

Improvement in motor and exploratory behavior in Rett syndrome mice with restricted ketogenic and standard diets.

Rett syndrome (RTT) is a rare X-linked autistic-spectrum neurological disorder associated with impaired energy metabolism, seizure susceptibility, progressive social behavioral regression, and motor impairment primarily in young girls. The objective of this study was to examine the influence of restricted diets, including a ketogenic diet (KD) and a standard rodent chow diet (SD), on behavior in male Mecp2(308/y) mice, a model of RTT. The KD is a high-fat, low-carbohydrate diet that has anticonvulsant efficacy in children with intractable epilepsy and may be therapeutic in children with RTT. Following an 11-day pretrial period, adult wild-type and mutant Rett mice were separated into groups that were fed either an SD in unrestricted or restricted amounts or a ketogenic diet (KetoCal) in restricted amounts for a total of 30 days. The restricted diets were administered to reduce mouse body weight by 20-23% compared to the body weight of each mouse before the initiation of the diet. All mice were subjected to a battery of behavioral tests to determine the influence of the diet on the RTT phenotype. We found that performance in tests of motor behavior and anxiety was significantly worse in male RTT mice compared to wild-type mice and that restriction of either the KD or the SD improved motor behavior and reduced anxiety. We conclude that although both restricted diets increased the tendency of Rett mice to explore a novel environment, the beneficial effects of the KD were due more to calorie restriction than to the composition of the diet. Our findings suggest that calorically restricted diets could be effective in reducing the anxiety and in improving motor behavior in girls with RTT.

Effects of postnatal dietary choline supplementation on motor regional brain volume and growth factor expression in a mouse model of Rett syndrome.

Nutritional status during pregnancy and lactation can influence behavioral and anatomical characteristics of several neurological disorders in the offspring, including Rett syndrome (RTT). RTT is associated with mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MeCp2), a transcriptional repressor that binds methylated DNA. In Mecp2(1lox) mice, a model of RTT, enhancing maternal nutrition through choline supplementation attenuates motor coordination deficits in the mutant offspring. Here, we examine alterations in brain volume and growth factor expression in the cerebellum and striatum, motor regions that may contribute to the improved behavioral performance seen with choline supplementation. Mecp2(1lox) dams were given choline in drinking water, and pups nursed from birth to weaning. Brains of male offspring were collected at postnatal day 42 for volumetric and growth factor expression analyses. Compared to wild-type mice, Mecp2(1lox) null mice had decreased whole brain, cerebellar and striatal volume. Choline supplementation had no effect on brain volume. Nerve growth factor and insulin-like growth factor-1 expression was similar between wild-type and Mecp2(1lox) mice while brain derived neurotrophic factor was reduced in Mecp2(1lox) mice. Choline supplementation increased striatal nerve growth factor expression in wild-type and Mecp2(1lox) mice, suggesting that neuronal proliferation and survival may contribute to improved motor performance in this model of RTT.

Methylation status in females with rett syndrome.

The authors studied methionine and creatine metabolism in females with Rett syndrome. Plasma metabolites (including methionine, homocysteine, guanidinoacetate) and urine creatine/creatinine ratios in 29 females with Rett syndrome were within the age-appropriate range. Although the authors have not been able to identify any abnormalities, it can be speculated that patients with Rett syndrome may benefit from dietary intervention to increase the supply of labile methyl groups to affected tissues.

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.

Ketogenic diet in Rett syndrome.

Treatment of Rett syndrome with the ketogenic diet has been reported only once and showed positive effects on seizure frequency and behavior. We report a patient with Rett syndrome who was treated with the ketogenic diet for 4 years. The diet was initiated at the age of 8 years owing to the patient's refractory epilepsy and led to a 70% reduction in seizures. Treatment with the ketogenic diet was also associated with improvements in contact and behavior. Diagnosis of Rett syndrome was confirmed by molecular detection of the Ser134Cys mutation in the MECP2 gene, which has previously been described only in classic Rett syndrome. This observation demonstrates that the ketogenic diet has a positive effect on Rett syndrome.

[Early-onset epileptic encephalopathy caused by CDKL5 mutation].

Two girls suffering from early-onset epileptic encephalopathy are described. Both girls had changes involving the gene CDKL5. They both had seizures in the first weeks of life and normal EEG interictally. Both developed infantile spasms and severe developmental defect. The epilepsy was difficult to treat.

Altered erythrocyte membrane fatty acid profile in typical Rett syndrome: effects of omega-3 polyunsaturated fatty acid supplementation.

This study mainly aims at examining the erythrocyte membrane fatty acid (FAs) profile in Rett syndrome (RTT), a genetically determined neurodevelopmental disease. Early reports suggest a beneficial effects of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) on disease severity in RTT. A total of 24 RTT patients were assigned to ω-3 PUFAs-containing fish oil for 12 months in a randomized controlled study (average DHA and EPA doses of 72.9, and 117.1mg/kgb.w./day, respectively). A distinctly altered FAs profile was detectable in RTT, with deficient ω-6 PUFAs, increased saturated FAs and reduced trans 20:4 FAs. FAs changes were found to be related to redox imbalance, subclinical inflammation, and decreased bone density. Supplementation with ω-3 PUFAs led to improved ω-6/ω-3 ratio and serum plasma lipid profile, decreased PUFAs peroxidation end-products, normalization of biochemical markers of inflammation, and reduction of bone hypodensity as compared to the untreated RTT group. Our data indicate that a significant FAs abnormality is detectable in the RTT erythrocyte membranes and is partially rescued by ω-3 PUFAs.

Anaplerotic triheptanoin diet enhances mitochondrial substrate use to remodel the metabolome and improve lifespan, motor function, and sociability in MeCP2-null mice.

Rett syndrome (RTT) is an autism spectrum disorder (ASD) caused by mutations in the X-linked MECP2 gene that encodes methyl-CpG binding protein 2 (MeCP2). Symptoms range in severity and include psychomotor disabilities, seizures, ataxia, and intellectual disability. Symptom onset is between 6-18 months of age, a critical period of brain development that is highly energy-dependent. Notably, patients with RTT have evidence of mitochondrial dysfunction, as well as abnormal levels of the adipokines leptin and adiponectin, suggesting overall metabolic imbalance. We hypothesized that one contributor to RTT symptoms is energy deficiency due to defective nutrient substrate utilization by the TCA cycle. This energy deficit would lead to a metabolic imbalance, but would be treatable by providing anaplerotic substrates to the TCA cycle to enhance energy production. We show that dietary therapy with triheptanoin significantly increased longevity and improved motor function and social interaction in male mice hemizygous for Mecp2 knockout. Anaplerotic therapy in Mecp2 knockout mice also improved indicators of impaired substrate utilization, decreased adiposity, increased glucose tolerance and insulin sensitivity, decreased serum leptin and insulin, and improved mitochondrial morphology in skeletal muscle. Untargeted metabolomics of liver and skeletal muscle revealed increases in levels of TCA cycle intermediates with triheptanoin diet, as well as normalizations of glucose and fatty acid biochemical pathways consistent with the improved metabolic phenotype in Mecp2 knockout mice on triheptanoin. These results suggest that an approach using dietary supplementation with anaplerotic substrate is effective in improving symptoms and metabolic health in RTT.

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.

Cholinergic hypofunction in MeCP2-308 mice: beneficial neurobehavioural effects of neonatal choline supplementation.

We studied the long-term effects of a postnatal choline supplementation (from birth till weaning) in the truncated MeCP2-308 mouse model of Rett syndrome. Adult male mutant hemizygous (hz) mice showed a reduction of locomotor activity compared to wild type (wt) littermates. Early choline treatment restored wt-like locomotor activity levels in hz mice. Reduced striatal choline acetyl transferase (ChAT) activity and decreased levels of cortical mRNA NGF were found in hz mice. Choline supplementation increased striatal ChAT activity and also enhanced NGF and BDNF expression in cortical and hippocampal regions. As a whole, postnatal choline supplementation attenuates some of the behavioural and neurobiological abnormalities of the Mecp2-308 phenotype.

Widened clinical spectrum of the Q128P MECP2 mutation in Rett syndrome.

CASE REPORT: We describe a female patient with Arnold Chiari type I malformation, atypical Rett syndrome characterized by postnatal onset microcephaly, stereotypic hand movements, ataxia, severe developmental delay, intractable tonic-clonic seizures, and a MECP2 mutation with a unique set of clinical findings. Implementation of a ketogenic diet resulted in decreased seizure activity and an improvement in the patient's degree of social relatedness with her family members. DISCUSSION: An early diagnosis of Rett syndrome allows families to maximize utilization of existing treatment modalities and seek appropriate genetic counseling and prenatal diagnoses. This case also provides further evidence for the treatment benefit of ketogenic diets for seizures in patients with Rett syndrome.