Neonatal onset of hot water reflex seizures in monozygotic twins subsequently manifesting episodes of alternating hemiplegia

Alternating hemiplegia of childhood: a distinct clinical entity and ATP1A3-related disorders: A narrative review

Alternating Hemiplegia of Childhood (AHC) is a rare disorder with onset in the first 18 months of life characterized by stereotyped paroxysmal manifestations of tonic and dystonic attacks, nystagmus with other oculomotor abnormalities, respiratory and autonomic dysfunctions. AHC is often associated with epileptic seizures and developmental delay. Hemiplegic paroxysm is the most remarkable symptom, although AHC includes a large series of clinical manifestations that interfere with the disease course. No cure is available and the treatment involves many specialists and therapies. Flunarizine is the most commonly used drug for reducing the frequency and intensity of paroxysmal events. Mutations in ATP1A2, particularly in ATP1A3, are the main genes responsible for AHC. Some disorders caused by ATP1A3 variants have been defined as ATP1A3-related disorders, including rapid-onset dystonia-parkinsonism, cerebellar ataxia, pes cavus, optic atrophy, sensorineural hearing loss, early infant epileptic encephalopathy, child rapid-onset ataxia, and relapsing encephalopathy with cerebellar ataxia. Recently, the term ATP1A3 syndrome has been identified as a fever-induced paroxysmal weakness and encephalopathy, slowly progressive cerebellar ataxia, childhood-onset schizophrenia/autistic spectrum disorder, paroxysmal dyskinesia, cerebral palsy/spastic paraparesis, dystonia, dysmorphism, encephalopathy, MRI abnormalities without hemiplegia, and congenital hydrocephalus. Herewith, we discussed about historical annotations of AHC, symptoms, signs and associated morbidities, diagnosis and differential diagnosis, treatment, prognosis, and genetics. We also reported on the ATP1A3-related disorders and ATP1A3 syndrome, as 2 recently established and expanded genetic clinical entities.

Long-term follow-up and novel genotype-phenotype analysis of monozygotic twins with ATP1A3 mutation in Alternating Hemiplegia of Childhood-2

Alternating Hemiplegia of Childhood (AHC) is a rare disorder characterized by frequent, transient attacks of hemiplegia involving either side of the body or both in association to several other disturbances including dystonic spells, abnormal ocular movements, autonomic manifestations, epileptic seizures and cognitive impairment. The clinical manifestations usually start before the age of 18 months. Two forms of the disorder known as AHC-1 (MIM#104290) and AHC-2 (MIM#614820) depends on mutations in ATP1A2 and ATP1A3 genes respectively, with over 75% of AHC caused by a mutation in the ATP1A3 gene. Herewith, we report serial clinical follow-up data of monozygotic (MZ) twin sisters, who presented in early life bath-induced dystonia, signs of acute encephalopathy at the age of 2 years, hemiplegic spells, and motor dysfunction after the age of 3 years, and in young/adult frequent episodes of headache with drastic reduction of paroxysmal motor attacks. The molecular analysis revealed a known pathogenic variant p.Asn773Ser (rs606231437) in ATP1A3 gene associated with an unusual and moderate AHC-2 phenotype, with mild cognitive impairment and lack of epilepsy. The aim of this study is to analyze the clinical phases of the MZ twins, and to investigate the novel genotype-phenotype correlation.

An 11-year follow-up study of neonatal-onset, bath-induced alternating hemiplegia of childhood in twins

The authors previously reported on the initial manifestations in a set of female twins, who presented soon after birth with bath-induced paroxysmal events each time they were immersed in a warm water bath. These episodes progressively ceased by the age of 36 months, replaced by paroxysmal episodes of alternating hemiplegia unrelated to water immersion. By age 4 years, the twins developed the classic features of alternating hemiplegia of childhood. Clinical outcomes at the age of 11 years are now reported. Standard and video-electroencephalograms showed a large, slow background activity followed by lower amplitude waves without focal abnormalities or other abnormal findings. This represents the first report on (a) alternating hemiplegia of childhood started with bath-induced paroxysmal episodes; (b) this condition in monozygotic twins; and (c) an 11-year follow-up study in which the twins continue to experience episodes of alternating hemiplegia in the setting of baseline cognitive impairment without epileptic episodes.

Bath-induced paroxysmal disorders in infancy

We reviewed those paroxysmal disorders of infancy and of the newborn in which the normal process of bathing may be an important trigger. We focused on infant bathing in normal temperature water (37 degrees C, range 36-38 degrees C) rather than in hot water that is above body temperature. Four principal diagnostic categories emerged: bathing epilepsy, alternating hemiplegia of childhood, hyperekplexia and paroxysmal extreme pain disorder. Bathing or water immersion epilepsy was the best studied and is arguably distinct from hot water epilepsy. The paroxysmal episodes previously attributed to aquagenic urticaria may have been examples of bathing epilepsy with a genetic component. Despite suggestions in the literature to the contrary, no convincing reports of bath-induced infantile syncope have been found. The underlying mechanisms of bath-induced paroxysmal disorders in infancy remain poorly understood, but all have autonomic manifestations and some if not all may be channelopathies.