Epileptic Encephalopathy, Early Infantile 47

Clinical Characteristics
Ocular Features: 

The fundus is normal early but optic atrophy with narrowed vessels develops eventually.  Cerebral visual impairment has been described.  VEPs were normal at 4 months of age in one patient.

Systemic Features: 

Tonic seizures have their onset in the first month of life.  These become refractory as documented by the EEG which shows severe background slowing, multifocal origins, and hypsarrhythmia.  Psychomotor development is severely delayed and accompanied by profound intellectual disability.  The two reported children were unable to stand and never developed speech.  Feeding difficulties requires tube feeding.  Microcephaly eventually develops along with axial hypotonia and limb ataxia.

Brain MRI was normal at 5 months of age in one individual but at 6 years old showed cerebellar atrophy.  Her younger male sibling at 2 months of age had a normal MRI but cerebellar atrophy was present at 3 years of age.  He died at 3.5 years while his older sib died at age 7 years.


Heterozygous mutations in the FGF12 gene (3q28-q29) are responsible for this condition.  One family with 2 affected children has been reported but neither parent carried the mutation in somatic cells suggesting germline mosaicism.

For autosomal recessive forms of early onset epileptic encephalopathy in this database see Epileptic Encephalopathy, Early Infantile 28 (616211) and Epileptic Encephalopathy, Early Infantile 48 (617276).

Treatment Options: 

No treatment is available for the general condition.  Complete supportive care is required.  Seizures are described as 'refractory' to treatment.

Article Title: 


Siekierska A, Isrie M, Liu Y, Scheldeman C, Vanthillo N, Lagae L, de Witte PA, Van Esch H, Goldfarb M, Buyse GM. Gain-of-function FHF1 mutation causes early-onset epileptic encephalopathy with cerebellar atrophy. Neurology. 2016 Jun 7;86(23):2162-70.

PubMedID: 27164707