[MIM 613 722, 614 959, 615 338,  616 645]

(Migrating partial epilepsy, EIMFS, MMPSI)

Rare. Variable transmission or de novo mutation of the KCNT1 gene (9q34.3). Epileptogenic encephalopathy. Other mutations in the same gene can lead to other phenotypes such as autosomal dominant nocturnal frontal epilepsy, West or Ohtahara syndrome, leukodystrophies, focal or multifocal epilepsies.

Seizures typically begin before 6 months of age and increase in frequency and severity, negatively affecting neurological development and often leading to a regression of mental capabilities and developmental disorders. They are essentially focal and motor but can also be tonic, clonic, myoclonic, spasms with a variable generalization. They are often accompanied by autonomic signs: profuse sweating, perioral cyanosis, apnea. They become almost continuous between 6 and 9 months of age and are resistant to treatment. One can also observe: predominantly axial hypotonia, microcephaly that appears around 12 months of age and sometimes choreoathetotic movements, dyskinesias and focal or generalized dystonia.

EEG: focal discharges migrating from a cortical area to a contiguous one and appearing independently in different locations. Frontal predominance with post-ictal suppression is sometimes observed. 

Imaging: normal before the onset of the seizures. Sometimes: delayed in myelinization, cerebellar atrophy, decrease in the volume of the hippocampus.

In some cases, the presence of arterial malformations has been observed: bronchopulmonary anastomoses of aortic origin (hemoptysis), arteriovenous fistulas, dilated cardiomyopathy.

Anesthetic implications:

treatment-resistant epilepsy (sometimes ketogenic diet); risk of vascular malformation (hemoptysis, signs of heart failure ?)

References :

-        Kawasaki Y, Kuki I, Ehara E, Murakami Y et al.
Three cases of KCNT1 mutations : malignant migrating partial seizures in infancy with massive systemic to pulmonary collateral arteries.
J Pediatr 2017 ; 191 :270-4.

-        Cassiba J, Bitton L, Mignot C, Doummar D, Heron B, Ducou Le Pointe H, Brenot P, Corvol H.
Pulmonary hemorrhage revealing multiple vascular malformations in a child with KCNT1 developmental epileptic encephalopathy.
J Pediatr 2021 ; 237 :311-2

Updated: October 2021