Absence of Mutation in the SLC2A1 Gene in a Cohort of Patients with Alternating Hemiplegia of Childhood (AHC)
ABSTRACT Alternating hemiplegia of childhood (AHC) is a rare neuropediatric disorder classically characterized by episodes of hemiplegia developing in the first months of life, various non-epileptic paroxysmal events and global neurological impairment. If the etiology is unresolved, the disorder is highly suspected to be monogenic with DE NOVO autosomal dominant mutations. A missense mutation in the SLC2A1 gene encoding the facilitative glucose transporter-1 (GLUT1) was recently described in a child fulfilling the existing criteria for the diagnosis of AHC, with the exception of age at onset, thus suggesting a clinical overlap between AHC and GLUT1 deficiency syndrome due to SLC2A1 mutations. We have studied a cohort of 23 patients to investigate whether patients with classical AHC harbor SLC2A1 mutations. Automated Sanger sequencing and MLPA analyses failed to detect any SLC2A1 mutations in the 23 patients analyzed, thus excluding mutations of this gene as a frequent cause of classical AHC.
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ABSTRACT: Alternating hemiplegia of childhood (AHC) is a rare neurological disorder characterised by early-onset episodes of hemiplegia, dystonia, various paroxysmal symptoms, and developmental impairment. Almost all cases of AHC are sporadic but AHC concordance in monozygotic twins and dominant transmission in a family with a milder phenotype have been reported. Thus, we aimed to identify de-novo mutations associated with this disease. We recruited patients with clinically characterised AHC from paediatric neurology departments in Germany and with the aid of a parental support group between Sept, 2004, and May 18, 2012. We used whole-exome sequencing of three proband-parent trios to identify a disease-associated gene and then tested whether mutations in the gene were also present in the remaining patients and their healthy parents. We analysed genotypes and characterised their associations with the phenotypic spectrum of the disease. We studied 15 female and nine male patients with AHC who were aged 8-35 years. ATP1A3 emerged as the disease-associated gene in AHC. Whole-exome sequencing showed three heterozygous de-novo missense mutations. Sequencing of the 21 remaining affected individuals identified disease-associated mutations in ATP1A3 in all patients, including six de-novo missense mutations and one de-novo splice-site mutation. Because ATP1A3 is also the gene associated with rapid-onset dystonia-parkinsonism (DYT12, OMIM 128235) we compared the genotypes and phenotypes of patients with AHC in our cohort with those of patients with rapid-onset dystonia-parkinsonism reported in the scientific literature. We noted overlapping clinical features, such as abrupt onset of dystonic episodes often triggered by emotional stress, a rostrocaudal (face to arm to leg) gradient of involvement, and signs of brainstem dysfunction, as well as clearly differentiating clinical characteristics, such as episodic hemiplegia and quadriplegia. Mutation analysis of the ATP1A3 gene in patients who met clinical criteria for AHC allows for definite genetic diagnosis and sound genetic counselling. AHC and rapid-onset dystonia-parkinsonism are allelic diseases related to mutations in ATP1A3 and form a phenotypical continuum of a dystonic movement disorder. Eva Luise and Horst Köhler Foundation for Humans with Rare Diseases.The Lancet Neurology 07/2012; 11(9):764-73. DOI:10.1016/S1474-4422(12)70182-5 · 21.82 Impact Factor
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ABSTRACT: Alternating hemiplegia of childhood is a rare, predominantly sporadic disorder. Diagnosis is clinical, and little is known about genetics. Glucose transporter 1 deficiency syndrome shares with alternating hemiplegia of childhood paroxysmal and nonparoxysmal symptoms. The aim of the study was to investigate glucose transporter 1 mutations in 30 Italian patients. Genetic material was analyzed by DNA amplification and glucose transporter 1 region sequencing. Mutational analysis findings of the SLC2A1 gene were negative in all patients. The pattern of movement disorders was reviewed. Interictal dystonia and multiple paroxysmal events were typical of alternating hemiplegia of childhood. In conclusion, alternating hemiplegia of childhood is a heterogeneous clinical condition, and although glucose transporter 1 deficiency can represent an undiagnosed cause of this disorder, mutational analysis is not routinely recommended. Alternatively, a careful clinical analysis and the 3-O-methyl-D-glucose uptake test can allow prompt identification of a subgroup of patients with alternating hemiplegia of childhood treatable with a ketogenic diet.Journal of child neurology 08/2012; 28(7). DOI:10.1177/0883073812452789 · 1.67 Impact Factor
Article: Alternating hemiplegia of childhood.[Show abstract] [Hide abstract]
ABSTRACT: Alternating hemiplegia of childhood (AHC) is a very rare disease characterized by recurrent attacks of loss of muscular tone resulting in hypomobility of one side of the body. The etiology of the disease due to ATP1A3 gene mutations in the majority of patients. Few familial cases have been described. AHC has an onset in the first few months of life. Hemiplegic episodes are often accompanied by other paroxysmal manifestations, such as lateral eyes and head deviation toward the hemiplegic side and a very peculiar monocular nystagmus. As the attack progresses, hemiplegia can shift to the other side of the body. Sometimes the attack can provoke bilateral paralysis, and these patients may have severe clinical impairment, with difficulty in swallowing and breathing. Hemiplegic attacks may be triggered by different stimuli, like bath in warm water, motor activity, or emotion. The frequency of attacks is high, usually several in a month or in a week. The duration is variable from a few minutes to several hours or even days. Sleep can stop the attack. Movement disorders such as dystonia and abnormal movements are frequent. Cognitive delay of variable degree is a common feature. Epilepsy has been reported in 50% of the cases, but seizure onset is usually during the third or fourth year of life. Many drugs have been used in AHC with very few results. Flunarizine has the most supportive anecdotal evidence regarding efficacy.Handbook of Clinical Neurology 01/2013; 112:821-6. DOI:10.1016/B978-0-444-52910-7.00001-5