Alternating Hemiplegia of Childhood (AHC)

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Disease Ontology 12 DOID:0050635 KEGG 37 H00998 MeSH 44 C536589 ICD10 33 G98 MESH via Orphanet 45 C536589

ICD10 via Orphanet 34 G98 UMLS via Orphanet 73 C0338488 Orphanet 59 ORPHA209978 ORPHA2131 UMLS 72 C0278110 C0338488

Genetics Home Reference : ²⁵ Alternating hemiplegia of childhood is a neurological condition characterized by recurrent episodes of temporary paralysis, often affecting one side of the body (hemiplegia). During some episodes, the paralysis alternates from one side of the body to the other or affects both sides at the same time. These episodes begin in infancy or early childhood, usually before 18 months of age, and the paralysis lasts from minutes to days. In addition to paralysis, affected individuals can have sudden attacks of uncontrollable muscle activity; these can cause involuntary limb movements (choreoathetosis), muscle tensing (dystonia), movement of the eyes (nystagmus), or shortness of breath (dyspnea). People with alternating hemiplegia of childhood may also experience sudden redness and warmth (flushing) or unusual paleness (pallor) of the skin. These attacks can occur during or separately from episodes of hemiplegia. The episodes of hemiplegia or uncontrolled movements can be triggered by certain factors, such as stress, extreme tiredness, cold temperatures, or bathing, although the trigger is not always known. A characteristic feature of alternating hemiplegia of childhood is that all symptoms disappear while the affected person is sleeping but can reappear shortly after awakening. The number and length of the episodes initially worsen throughout childhood but then begin to decrease over time. The uncontrollable muscle movements may disappear entirely, but the episodes of hemiplegia occur throughout life. Alternating hemiplegia of childhood also causes mild to severe cognitive problems. Almost all affected individuals have some level of developmental delay and intellectual disability. Their cognitive functioning typically declines over time.

MalaCards based summary : Alternating Hemiplegia of Childhood, also known as alternating hemiplegia, is related to adrenal hypoplasia, congenital and familial hemiplegic migraine, and has symptoms including hemiplegia, hemiplegia, flaccid and hemiplegia, transient. An important gene associated with Alternating Hemiplegia of Childhood is ATP1A2 (ATPase Na+/K+ Transporting Subunit Alpha 2), and among its related pathways/superpathways are Aldosterone-regulated sodium reabsorption and Endocrine and other factor-regulated calcium reabsorption. The drugs Glycerol and Sodium oxybate have been mentioned in the context of this disorder. Affiliated tissues include eye, skin and brain, and related phenotypes are behavior/neurological and homeostasis/metabolism

Disease Ontology : ¹² A hemiplegia characterized by recurrent episodes of temporary weakness or complete paralysis on one or both sides of the body.

NIH Rare Diseases : ⁵³ Alternating hemiplegia of childhood (AHC) is a neurological disorder that usually affects children before 18 months of age. Classic AHC causes recurrent episodes of paralysis (hemiplegia) that involve one or both sides of the body, multiple limbs, or a single limb. The paralysis may affect different parts of the body at different times and may be brief or last for several days. A characteristic feature of AHC is that symptoms disappear during sleep and return upon waking. Many affected children display some degree of developmental delay, abnormal eye (oculomotor) movements, uncontrolled limb movements (including ataxia, dystonia, and choreoathetosis) and seizures. The majority of cases of AHC are caused by a new change (called a mutation or pathogenic variant) in the ATP1A3 gene that is not inherited. Thus, most patients with AHC do not have a family history of the disorder. A small number of cases of AHC are caused by changes in the ATP1A2 gene. When this condition does run in families, it follows an autosomal dominant pattern of inheritance.Treatment is limited to therapies that can help reduce the severity and duration of symptoms.

NINDS : ⁵⁴ Alternating hemiplegia is a rare neurological disorder that develops in childhood, most often before the child is 18 months old. The disorder is characterized by recurrent episodes of paralysis that involve one or both sides of the body, multiple limbs, or a single limb. The paralysis may affect different parts of the body at different times and may be brief or last for several days. Oftentimes these episodes will resolve after sleep. Affected children may also have abnormal movements involving stiffening or "dance-like" movements of a limb, as well as walking and balance problems. Some children have seizures. Children may have normal or delayed development. There are both benign and more serious forms of the disorder. Alternating hemiplegia is primarily caused by mutations in the ATP1A3 gene. Occasionally, a mutation in the ATP1A2 gene is involved in the condition. These genes provide instructions for making very similar proteins. Mutations in these genes reduce the activity of an enzyme called Na+/K+ ATPase, which affects the signals that control muscle movement. However, it not yet clear how the reduced enzyme activity leads to the symptoms of the disorder.

KEGG : ³⁷ Alternating hemiplegia of childhood (AHC) is a rare disorder with onset before 18 months of age. The earliest manifestations of AHC are recurrent bilateral attacks of hemiplegia lasting minutes to days, abnormal ocular movements, and autonomic disturbances. A characteristic feature of AHC is the disappearance of all abnormalities when the child falls asleep.

Wikipedia : ⁷⁵ Alternating hemiplegia of childhood is an ultra-rare neurological disorder named for the transient... more...

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