In vitro study of ATP1A3 p.Ala275Pro mutant causing alternating hemiplegia of childhood and rapid-onset dystonia-parkinsonism.

Introduction: We previously reported that ATP1A3 c.823G>C (p.Ala275Pro) mutant causes varying phenotypes of alternative hemiplegia of childhood and rapid-onset dystonia-parkinsonism in the same family. This study aims to investigate the function of ATP1A3 c.823G>C (p.Ala275Pro) mutant at the cellular and zebrafish models. Methods: ATP1A3 wild-type and mutant Hela cell lines were constructed, and ATP1A3 mRNA expression, ATP1A3 protein expression and localization, and Na+-K+-ATPase activity in each group of cells were detected. Additionally, we also constructed zebrafish models with ATP1A3 wild-type overexpression (WT) and p.Ala275Pro mutant overexpression (MUT). Subsequently, we detected the mRNA expression of dopamine signaling pathway-associated genes, Parkinson's disease-associated genes, and apoptosisassociated genes in each group of zebrafish, and observed the growth, development, and movement behavior of zebrafish. Results: Cells carrying the p.Ala275Pro mutation exhibited lower levels of ATP1A3 mRNA, reduced ATP1A3 protein expression, and decreased Na+-K+-ATPase activity compared to wild-type cells. Immunofluorescence analysis revealed that ATP1A3 was primarily localized in the cytoplasm, but there was no significant difference in ATP1A3 protein localization before and after the mutation. In the zebrafish model, both WT and MUT groups showed lower brain and body length, dopamine neuron fluorescence intensity, escape ability, swimming distance, and average swimming speed compared to the control group. Moreover, overexpression of both wild-type and mutant ATP1A3 led to abnormal mRNA expression of genes associated with the dopamine signaling pathway and Parkinson's disease in zebrafish, and significantly upregulated transcription levels of bad and caspase-3 in the apoptosis signaling pathway, while reducing the transcriptional level of bcl-2 and the bcl-2/bax ratio. Conclusion: This study reveals that the p.Ala275Pro mutant decreases ATP1A3 protein expression and Na+/K+-ATPase activity. Abnormal expression of either wild-type or mutant ATP1A3 genes impairs growth, development, and movement behavior in zebrafish.

ATP1A3 regulates protein synthesis for mitochondrial stability under heat stress.

Pathogenic variants in ATP1A3, the gene encoding the α3 subunit of the Na+/K+-ATPase, cause alternating hemiplegia of childhood (AHC) and related disorders. Impairments in Na+/K+-ATPase activity are associated with the clinical phenotype. However, it remains unclear whether additional mechanisms are involved in the exaggerated symptoms under stressed conditions in patients with AHC. We herein report that the intracellular loop (ICL) of ATP1A3 interacted with RNA-binding proteins, such as Eif4g (encoded by Eif4g1), Pabpc1 and Fmrp (encoded by Fmr1), in mouse Neuro2a cells. Both the siRNA-mediated depletion of Atp1a3 and ectopic expression of the p.R756C variant of human ATP1A3-ICL in Neuro2a cells resulted in excessive phosphorylation of ribosomal protein S6 (encoded by Rps6) and increased susceptibility to heat stress. In agreement with these findings, induced pluripotent stem cells (iPSCs) from a patient with the p.R756C variant were more vulnerable to heat stress than control iPSCs. Neurons established from the patient-derived iPSCs showed lower calcium influxes in responses to stimulation with ATP than those in control iPSCs. These data indicate that inefficient protein synthesis contributes to the progressive and deteriorating phenotypes in patients with the p.R756C variant among a variety of ATP1A3-related disorders.

Characteristics of non-sleep related apneas in children with alternating hemiplegia of childhood.

BACKGROUND: Non-sleep related apnea (NSA) has been observed in alternating hemiplegia of childhood (AHC) but has yet to be characterized. GOALS: Investigate the following hypotheses: 1) AHC patients manifest NSA that is often severe. 2) NSA is usually triggered by precipitating events. 3) NSA is more likely in patients with ATP1A3 mutations. METHODS: Retrospective review of 51 consecutive AHC patients (ages 2-45 years) enrolled in our AHC registry. NSAs were classified as mild (not needing intervention), moderate (needing intervention but not perceived as life threatening), or severe (needing intervention and perceived as life threatening). RESULTS: 19/51 patients (37 %) had 52 NSA events (6 mild, 11 moderate, 35 severe). Mean age of onset of NSA (± Standard Error of the Mean (SEM)): 3.8 ± 1.5 (range 0-24) years, frequency during follow up was higher at younger ages as compared to adulthood (year 1: 2.2/year, adulthood: 0.060/year). NSAs were associated with triggering factors, bradycardia and with younger age (p < 0.008 in all) but not with mutation status (p = 0.360). Triggers, observed in 17 patients, most commonly included epileptic seizures in 9 (47 %), anesthesia, AHC spells and intercurrent, stressful, conditions. Management included use of pulse oximeter at home in nine patients, home oxygen in seven, intubation/ventilatory support in seven, and basic CPR in six. An additional patient required tracheostomy. There were no deaths or permanent sequalae. CONCLUSIONS: AHC patients experience NSAs that are often severe. These events are usually triggered by seizures or other stressful events and can be successfully managed with interventions tailored to the severity of the NSA.

Development and testing of methods to record and follow up spells in patients with alternating hemiplegia of childhood.

BACKGROUND: Developing methods to record Alternating Hemiplegia of Childhood (AHC) spells is essential for clinical trials and patient care. OBJECTIVES: Test the following hypotheses: 1) Video-library training improves participants' ability to correctly identify AHC spells. 2) A custom-designed event-calendar with weekly reviews results in consistent documentation of such events over time. 3) Use of an electronic diary (e-Diary) to register events is a useful tool. METHODS: 1) A video-library of AHC type spells was developed along with specific training; the effect of the training was tested in 36 caregivers. 2) An event-calendar was similarly developed and provided to 5 caregivers with weekly videoconference meetings for 8 weeks. 3) An e-Diary was developed and offered to 33 patients; time of usage and caregivers' feedback (telephone interview) were analyzed. RESULTS: 1) Video-library training: Wilcoxon test showed improvement in caregiver identification of spells (p = 0.047), Cohen's Kappa demonstrated high degree of agreement between caregivers'-experts' classifications (>0.9). 2) Event-calendar: 96.42% of entries had complete information; this did not change during follow up (p = 0.804). 3) e-Diary: whereas 52% of respondents used the e-Diary when offered (duration: 10.5 ± 8.1 months), 96.3% indicated they would use it in future studies. Those who used it for 13 months, were very likely to use it during the rest of that year. CONCLUSIONS: Video-library training improved spell identification. Calendar with weekly reviews resulted in a sustained and consistent record keeping. Caregivers' e-Diary feedback was encouraging with long-term usage in many. These approaches could be helpful for AHC and, potentially, in similar disorders.

Precision therapy for a medically actionable ATP1A3 variant from a genomic medicine program in an underserved population.

BACKGROUND: Genomic medicine is revolutionizing the diagnosis of rare diseases, but the implementation has not benefited underrepresented populations to the same degree. Here, we report the case of a 7-year-old boy with hypotonia, global developmental delay, strabismus, seizures, and previously suspected mitochondrial myopathy. This proband comes from an underrepresented minority and was denied exome sequencing by his public insurance. METHODS: After informed consent was obtained, buccal cells from the proband were collected and whole exome sequencing was performed. Illumina Dragen and Emedgene software was used to analyze the data at Baylor Genetics. The variants were further intepreted according to ACMG guidelines and the patient's phenotype. RESULTS: Through whole-exome sequencing (WES) under the Community Texome project, he was found to have a heterozygous de novo pathogenic variant in the ATP1A3 gene located on chromosome 19q13. CONCLUSION: In retrospect, his symptomatology matches the known medical conditions associated with the ATP1A3 gene namely Alternating Hemiplegia of Childhood 2 (AHC), a rare autosomal dominant disorder with an incidence of 1 in one million. His single nucleotide variant, (c.2401G>A, p.D801N), is predicted to be damaging. The specific amino acid change p.D801N has been previously reported in ClinVar along with the allelic variant p.D801Y and both are considered pathogenic. The identification of this variant altered medical management for this patient as he was started on a calcium antagonist and has reported no further hemiplegic episodes. This case illustrates the value of implementing genomic medicine for precision therapy in underserved populations.

Brain structural changes in alternating hemiplegia of childhood using single-case voxel-based morphometry analysis.

BACKGROUND AND PURPOSE: Alternating hemiplegia of childhood (AHC) is a rare neurodevelopmental disease caused by ATP1A3 mutations. Using voxel-based morphometry (VBM) analysis, we compared an AHC patient cohort with controls. Additionally, with single-case VBM analysis, we assessed the associations between clinical severity and brain volume in patients with AHC. MATERIALS AND METHODS: To investigate structural brain changes in gray matter (GM) and white matter (WM) volumes between 9 patients with AHC and 20 age-matched controls, VBM analysis was performed using three-dimensional T1-weighted magnetic resonance imaging. Single-case VBM analysis was also performed on nine patients with AHC to investigate the associations between the respective volumes of GM/WM differences and the motor level, cognitive level, and status epilepticus severity in patients with AHC. RESULTS: Compared with controls, patients with AHC showed significant GM volume reductions in both hippocampi and diffuse cerebellum, and there were WM reductions in both cerebral hemispheres. In patients with AHC, cases with more motor dysfunction, the less GM/WM volume of cerebellum was shown. Three of the six cases with cognitive dysfunction showed a clear GM volume reduction in the insulae. Five of the six cases with status epilepticus showed the GM volume reduction in hippocampi. One case had severe status epilepticus without motor dysfunction and showed no cerebellar atrophy. CONCLUSION: With single-case VBM analysis, we could show the association between region-specific changes in brain volume and the severity of various clinical symptoms even in a small sample of subjects.

The clinical spectrum associated with ATP1A2 variants in Chinese pediatric patients.

PURPOSE: To evaluate the clinical spectrum associated with ATP1A2 variants in Chinese children with hemiplegia, migraines, encephalopathy or seizures. METHODS: Sixteen children (12 males and 4 females), including ten patients with ATP1A2 variants whose cases had been published previously, were identified using next-generation sequencing. RESULTS: Fifteen patients had FHM2 (familial hemiplegic migraine type 2), including three who had AHC (alternating hemiplegia of childhood) and one who had drug-resistant focal epilepsy. Thirteen patients had DD (developmental delay). The onset of febrile seizures, which occurred between 5 months and 2 years 5 months (median 1 year 3 months) was earlier than the onset of HM (hemiplegic migraine), which occurred between 1 year 5 months and 13 years (median 3 years 11 months). Disturbance of consciousness subsided first, at 40 h to 9 days (median 4.5 days); hemiplegia and aphasia were resolved slowly, taking 30 min to 6 months (median 17.5 days) for the former and 24 h to over 1 year (median 14.5 days) for the latter. Cranial MRI showed edema in the cerebral hemispheres, mainly the left hemisphereacute attacks. All thirteen FHM2 patients recovered to baseline in 30 min to 6 months. Fifteen patients had between 1 and 7 (median 2) total attacks between the baseline and follow-up timepoints. We report twelve missense variants, including a novel variant ATP1A2 variant, p.G855E. CONCLUSIONS: The known genotypic and phenotypic spectra of Chinese patients with ATP1A2-related disorders were further expanded. Recurrent febrile seizures and DD combined with paroxysmal hemiplegia and encephalopathy should raise the clinical suspicion of FHM2. The avoidance of triggers and thus the prevention of attacks may be the most effective therapy for FHM2.

A novel heterozygous ATP1A2 pathogenic variant in a Chinese child with MELAS-like alternating hemiplegia.

BACKGROUND: Pathogenic variants of ATP1A2 (OMIM ID: 182340) are usually associated with familial hemiplegic migraine type 2 (FHM-2), alternating hemiplegia of childhood (AHC), early infantile epileptic encephalopathy (EIEE), transient cytotoxic edema, and so on. Here, we present a novel heterozygous ATP1A2 variant in a girl with alternating hemiplegia, febrile seizures, developmental delay (which subsequently subsided), and MELAS-like syndrome (as indicated by brain MRI). The patient did not experience migraine with aura. METHODS: The patient was an 8-year-old girl with normal growth and development. Beginning from the age of 3 years and 8 months, the patient experienced several episodes of alternating limb paralysis. The episodes were accompanied by the appearance of MELAS-like findings on brain MRI, which corresponded to the hemiplegia. There were abnormal linear signals in the cerebral cortex on the opposite side of the hemiplegic limb. Each time the patient recovered from hemiplegia, and each time MRI showed no lesions remained after recovery. No obvious abnormality was found in other examinations. Finally, the patient underwent whole-exome sequencing (WES). RESULTS: WES revealed a novel and de novo heterozygous variant in the ATP1A2 (NM_000702.3) c.335C>A:p.Ala112Asp (not previously reported). We examined the variant position in the 3D protein structure and found that a missense mutation at this site is a nonconservative substitution. The variation is nonpolymorphic. It occurs at a very low frequency in the population, and its ACMG classification is likely pathogenic. CONCLUSION: At present, there are limited reports of mutations in the ATP1A2 gene causing AHC. This is the first case of brain MRI showing MELAS-like imaging in an AHC patient, and more cases are needed for verification. Early genetic testing and family screening can aid in the diagnosis and treatment of genetic diseases. The relationship between ATP1A2 gene mutation genotype and clinical phenotype needs to be further studied.

Disease mutations of human α3 Na+/K+-ATPase define extracellular Na+ binding/occlusion kinetics at ion binding site III.

Na+/K+-ATPase, which creates transmembrane electrochemical gradients by exchanging 3 Na+ for 2 K+, is central to the pathogenesis of neurological diseases such as alternating hemiplegia of childhood. Although Na+/K+-ATPase has 3 distinct ion binding sites I-III, the difficulty of distinguishing ion binding events at each site from the others hinders kinetic study of these transitions. Here, we show that binding of Na+ at each site in the human α3 Na+/K+-ATPase can be resolved using extracellular Na+-mediated transient currents. When Na+/K+-ATPase is constrained to bind and release only Na+, three kinetic components: fast, medium, and slow, can be isolated, presumably corresponding to the protein dynamics associated with the binding (or release depending on the voltage step direction) and the occlusion (or deocclusion) of each of the 3 Na+. Patient-derived mutations of residues which coordinate Na+ at site III exclusively impact the slow component, demonstrating that site III is crucial for deocclusion and release of the first Na+ into the extracellular milieu. These results advance understanding of Na+/K+-ATPase mutation pathogenesis and provide a foundation for study of individual ions' binding kinetics.

Anesthetic Implications in Alternating Hemiplegia of Childhood: A Case Report.

The following case report describes a 13-year-old child with alternating hemiplegia of childhood (AHC) who underwent magnetic resonance imaging MRI with general anesthesia and experienced a hemiplegic spell, seizure, apnea, and sudden cardiac arrest with successful resuscitation. AHC is a rare neurodevelopmental disorder characterized by repeated episodes of weakness or paralysis affecting one or both sides of the body and multiple other neurologic problems. The challenges associated with this disorder include management of developmental delay, dystonia, hemiplegia, cerebrovascular dysfunction, apnea, and autonomic dysfunction. The current literature is extremely limited in describing the effects of general anesthesia for a patient with AHC. While the neurologic manifestations of AHC are well described, autonomic dysfunction and the potential for sudden cardiac arrest have not been widely reported. To our knowledge, this is the first case report to emphasize anesthetic considerations in a pediatric patient with AHC, specifically the unrecognized potential for cardiac arrhythmia and sudden cardiac arrest.

Molecular and clinical characteristics of ATP1A3-related diseases.

Objective: With detailed studies of ATP1A3-related diseases, the phenotypic spectrum of ATP1A3 has greatly expanded. This study aimed to potentially identify the mechanisms by which ATP1A3 caused neurological dysfunction by analyzing the clinical features and phenotypes of ATP1A3-related diseases, and exploring the distribution patterns of mutations in the subregions of the ATP1A3 protein, thus providing new and effective therapeutic approaches. Methods: Databases of PubMed, Online Mendelian Inheritance in Man, and Human Gene Mutation Database, Wanfang Data, and Embase were searched for case reports of ATP1A3-related diseases. Following case screening, we collected clinical information and genetic testing results of patients, and analyzed the disease characteristics on the clinical phenotype spectrum associated with mutations, genetic characteristics of mutations, and effects of drug therapy. Results: We collected 902 clinical cases related to ATP1A3 gene. From the results of previous studies, we further clarified the clinical characteristics of ATP1A3-related diseases, such as alternating hemiplegia of childhood (AHC), rapid-onset dystonia-parkinsonism; cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss syndrome, and relapsing encephalopathy with cerebellar ataxia, frequency of mutations in different phenotypes and their distribution in gene and protein structures, and differences in mutations in different clinical phenotypes. Regarding the efficacy of drug treatment, 80 of the 124 patients with AHC were treated with flunarizine, with an effectiveness rate of ~64.5%. Conclusions: Nervous system dysfunction due to mutations of ATP1A3 gene was characterized by a group of genotypic-phenotypic interrelated disease pedigrees with multiple clinical manifestations. The presented results might help guide the diagnosis and treatment of ATP1A3-related diseases and provided new ideas for further exploring the mechanisms of nervous system diseases due to ATP1A3 mutations.

The impact of Transcranial Magnetic Stimulation (TMS) on seizure course in people with and without epilepsy.

Objective: To elucidate the effects of single and paired-pulse TMS on seizure activity at electrographic and clinical levels in people with and without epilepsy. Methods: A cohort of 35 people with epilepsy, two people with alternating hemiplegia of childhood (AHC) with no epilepsy, and 16 healthy individuals underwent single or paired-pulse TMS combined with EEG. Clinical records and subject interviews were used to examine seizure frequency four weeks before and after TMS. Results: There were no significant differences in seizure frequency in any subject after TMS exposure. There was no occurrence of seizures in healthy individuals, and no worsening of hemiplegic attacks in people with AHC. Conclusions: No significant changes in seizure activity were found before or after TMS. Significance: This study adds evidence on the safety of TMS in people with and without epilepsy with follow-up of four weeks after TMS.

Characterization of sedation and anesthesia complications in patients with alternating hemiplegia of childhood.

BACKGROUND: Alternating hemiplegia of childhood (AHC) pathophysiology suggests predisposition to sedation and anesthesia complications. GOALS: Hypotheses: 1) AHC patients experience high rates of sedation-anesthesia complications. 2) ATP1A3 mutation genotype positivity, age, and AHC severity correlate with more severe complications. 3) Prior short QTc correlates with cardiac rhythm complications. METHODS: Analysis of 34 consecutive AHC patients who underwent sedation or anesthesia. Classification of complications: mild (not requiring intervention), moderate (intervention), severe (intervention, risk for permanent injury or potential life-threatening emergency). STATISTICS: Fisher Exact test, Spearman correlations. RESULTS: These patients underwent 129 procedures (3.79 ± 2.75 procedures/patient). Twelve (35%) experienced complications during at least one procedure. Fourteen/129 procedures (11%) manifested one or more complications (2.3% mild, 7% moderate, 1.6% severe). Of the total 20 observed complications, six (33.3%) were severe: apneas (2), seizures (2), bradycardia (1), ventricular fibrillation that responded to resuscitation (1). Moderate complications: non-life-threatening bradycardias, apneas, AHC spells or seizures. Complications occurred during sedation or anesthesia and during procedures or recovery periods. Patients with disease-associated ATP1A3 variants were more likely to have moderate or severe complications. There was no correlation between complications and age or AHC severity. Presence of prior short QTc correlated with cardiac rhythm complications. After this series was analyzed, another patient had severe recurrent laryngeal dystonia requiring tracheostomy following anesthesia with intubation. CONCLUSIONS: During sedation or anesthesia, AHC patients, particularly those with ATP1A3 variants and prior short QTc, are at risk for complications consistent with AHC pathophysiology. Increased awareness is warranted during planning, performance, and recovery from such procedures.

Non-Stationary Outcome of Alternating Hemiplegia of Childhood into Adulthood.

BACKGROUND: Although described as non-progressive, alternating hemiplegia of childhood (AHC) can display a sudden deterioration, anecdotally reported mainly in childhood. Outcome in adulthood is uncertain. OBJECTIVES: Aim of this study is to describe the long-term follow-up of neurological function in adults with AHC. METHODS: Seven adults with AHC were included in this retrospective single-center study. Clinical history and previous investigation data were gathered from the review of medical records. Video-documented neurological examination was performed at the last follow-up visit in four out of the seven reported indivisuals. RESULTS: Over a median follow-up of 16 years, neurological outcome and trajectories were heterogeneous. All individuals showed new neurological signs or symptoms. Three experienced a serious irreversible neurological deterioration after prolonged quadriplegic episodes and/or status epilepticus in their second or third decade. One patient died at age 29. CONCLUSIONS: This video-series suggests that AHC in adulthood is not stationary; larger cohorts are needed to identify genotype-phenotype correlations and clinically useful outcome predictors.

Alternating Hemiplegia of Childhood: neurological comorbidities and intrafamilial variability.

BACKGROUND: Alternating of Childhood (AHC) is an uncommon and complex disorder characterized by age of onset before 18 months with recurrent hemiplegia of one or either sides of the body or quadriplegia. The disorder is mainly caused by mutations in ATP1A3 gene, and to a lesser extent in ATP1A2 gene. In AHC neurological co-morbidities are various and frequently reported including developmental delay, epilepsy, tonic or dystonic spells, nystagmus,autonomic manifestations with intrafamilial variability. CASE PRESENTATION: Clinical and genetic findings of a couple of twins (Family 1: Case 1 and Case 2) and a couple of siblings (Family 2: Case 3 and Case 4) coming from two different Italian families affected by AHC were deeply examined. In twins of Family 1, a pathogenic variant in ATP1A3 gene (c.2318A>G) was detected. In siblings of Family 2, the younger brother showed a novel GRIN2A variant (c.3175 T > A), while the older carried the same GRIN2A variant, and two missense mutations in SCNIB (c.632 > A) and KCNQ2 (1870 G > A) genes. Clinical manifestations of the four affected children were reported along with cases of AHC drawn from the literature. CONCLUSIONS: Hemiplegic episode is only a sign even if the most remarkable of several and various neurological comorbidities in AHC affected individuals. Molecular analysis of the families here reported showed that clinical features of AHC may be also the result of an unexpected genetic heterogeneity.

Different phenotypes of neurological diseases, including alternating hemiplegia of childhood and rapid-onset dystonia-parkinsonism, caused by de novo ATP1A3 mutation in a family.

BACKGROUND: The spectrum of neurological diseases related to ATP1A3 gene mutations is highly heterogeneous and exhibits different phenotypes. Phenotype overlaps, including alternating hemiplegia of childhood (AHC), early infantile epileptic encephalopathy, and rapid-onset dystonia-parkinsonism (RDP), can also occur at extremely low incidences. Currently, over 90 types of pathogenic mutations have been identified in ATP1A3. PATIENTS AND METHODS: The family of a 2-year-11-month-old proband with AHC was recruited for this clinical investigation. The proband was screened for candidate mutation gene sites using next-generation sequencing and target-region capture technology. Sanger sequencing was used to identify carriers among family members. RESULTS: The mother of the proband with AHC was diagnosed with dystonia (later diagnosed as RDP). The biochemical and immune indices of the proband and the mother were not abnormal. Moreover, brain imaging of the proband revealed no significant abnormalities. However, the electroencephalogram of the mother was mildly abnormal, with no spike wave discharge. Brain MRI revealed slight cerebellar atrophy. Electromyography revealed neurogenic damage, with a decrease in the conduction velocity of the left ulnar and radial nerves. Based on the sequencing data, both the proband and her mother carried c.823G > C p. (Ala275Pro) heterozygotes; other family members were not identified as carriers. With a PolyPhen-2 score of 0.997 and SIFT score of 0.001, this mutation can be considered damaging. CONCLUSION: Family genotype-phenotype correlation analysis revealed that the phenotype and gene mutation were co-segregated, suggesting that it may be a pathogenic mutation.

Progression of alternating hemiplegia of childhood-related focal epilepsy to electrical status epilepticus in sleep with reversible encephalopathy.

Mutations in the ATP1A3 gene (which encodes the main α subunit in neuronal Na+/K+-ATPases) cause various neurological syndromes including alternating hemiplegia of childhood. This rare disorder is characterized by paroxysmal episodes of hemiplegia, dystonia, oculomotor abnormalities, and occasionally developmental regression. Approximately 50% of alternating hemiplegia of childhood patients also have epilepsy, which is either focal or generalized. Seizures are often drug resistant. We report a 10-year-old girl with the D801N ATP1A3 mutation and alternating hemiplegia of childhood who manifested with drug-resistant focal seizures as an infant and throughout childhood. At the age of about10.5 years, her epilepsy evolved into electrical status epilepticus in sleep with generalized discharges. These changes coincided with developmental regression consistent with epileptic encephalopathy. Additionally, MRI and MR spectroscopy showed new cortical atrophy and markedly depressed N-acetyl aspartate peaks compared to previous normal studies. Electrical status epilepticus in sleep resolved after medication adjustments. She, now, only four months after her diagnosis of electrical status epilepticus in sleep, has regained most of the skills that were lost only a few months earlier. Our observations document that alternating hemiplegia of childhood can result in the above-described unique features; particularly, progression of focal epilepsy to electrical status epilepticus in sleep with generalized features and reversible epileptic encephalopathy.