[MIM 139 311]

Acronym for Guanine Nucleotide-Alpha O1

Very rare: only a hundred cases have been described. Autosomal dominant transmission or de novo mutation of the gene encoding the GNAO1 protein (16q13), an alpha subunit of the heterotrimeric guanine nucleotide-binding proteins (G proteins), a large family of signal-transducing molecules. The GNAO1 disorder was initially defined as early infantile epileptic encephalopathy 17 (see Ohtahara syndrome). However, the severity of epilepsy can vary significantly, and some GNAO1 patients do not have epilepsy.

A broad spectrum of symptoms are possible:

-        developmental delay,

-        hypotonia, epilepsy,

-        movement disorders: chorea: rapid, irregular, non-stereotyped involuntary movements and dystonia: involuntary muscle contractions resulting in twisting or repetitive movements and abnormal postures, which in severe episodes can lead to status dystonicus

Treatment is difficult : deep brain stimulation, ketogenic diet, antiepileptics, clonidine

Anesthetic implications: 

development delay, severely polyhandicapped child, epilepsy.

References:

-         Ananth AL, Robichaux-Viehoever A, Kim Y-M, Hanson-Kahn A, Cox  R, Enns GM et al. 
Clinical course of six children with GNAO1 mutations causing a severe and distinctive movement disorder. 
Pediatr Neurol 2016; 59: 81-4.

Updated: January 2020