Alternating Hemiplegia of Childhood (AHC)
|In 1971 Verret and Steele reported eight patients they have followed from 1953 up to 1969, that suffer from intermittent hemiparesis beginning from infancy or early childhood. The authors suggested that , instead, these cases present a distinct clinical entity, namely Alternating Hemiplegia (in) Childhood and it should be differentiated from convulsive disorders based on the specific profile of the symptoms and when no seizure activity is recorded on EEGs and cerebral artheriography is normal.|
Bourgeois, Aicardi and Goutières studied 22 patients in France and in 1993 and established the clinical diagnostic criteria for Alternating Hemiplegia (of) Childhood:
AHC1: In 2004, in a kindred with a complex phenotype including AHC and seizures, Bassi et al and Swoboda et al found a novel heterozygous mutation in the ATP1A2 gene, coding for the a2 subunit of the Na,K pump. None of the tested typical AHC cases however was found positive for ATP1A2 gene mutations.
- onset before 18 months of age;
- occurrence of hemiplegia, tonic or dystonic attacks, nystagmus, dyspnea and other autonomic phenomena;
- dissapearence of these symptoms with sleep and reappearence 10 to 20 minutes after awakening;
- episodes of quadriplegia that occuring either when a hemiplegia shifts from one side to the other or as an isolated manifestation;
- development of cognitive impairment and of a choreoathetotic movement disorder.
AHC2: In 2012, several labs (Heinzen et al, Rosewich et al, Genome Diagnostics Nijmegen, Ishii et al.) used next-generation sequencing (NGS) to screen for de novo mutations in AHC patients and identified missense mutations in the ATP1A3 gene in the majority of these cases.