Abstracts

Rationale: Early infantile epileptic encephalopathy (EIEE) is defined as a severe form of age related epileptic encephalopathies that occurs within the first three months of life in the form of generalized tonic-clonic seizure and is associated with developmental delay or developmental regression. Metabolic disorders, brain abnormalities and genetic variants with certain gene mutations are considered the major etiologies for EIEE. One of which is a highly conserved gene, SYNJ1 (Synaptojanin 1) mutation. As a matter of fact, SYNJ1 mutation can be the causation of two different disease entities, in which its loss of function result in degenerative nerve diseases with intractable seizures and taupathies. Another variant, a homozygous missense mutation of SYNJ1 demonstrate early onset parkinsonism. Here, we further describe six patients from consanguineous Arabian families with intractable seizures, global developmental delay, generalized hypotonia, feeding difficulties and failure to thrive.

Methods: Whole-exome sequence was carried out and identified homozygous loss of function variants of SYNJ1 mutation.

Results: Whole-exome sequence was carried out and identified homozygous loss of function variants of SYNJ1 mutation. EEG findings are mainly epileptiform discharges showing hypsarrhythmia; as of brain MRI, there were findings of diffuse brain atrophy.

Conclusions: In this study, we bring six additional patients to eight previously published cases, a total of fourteen, and conclude that SYNJ1 variants should be established with diagnosing patients with infantile epileptic encephalopathy, global developmental delay, and generalized hypotonia with hypsarrhythmia. In addition to further delineating the spectrum of SYNJ1 mutations and its presenting phenotypes with the possible correlation of seizures and tau-pathies to juvenile parkonsism.

Funding: Please list any funding that was received in support of this abstract.: No funds.