Abstract Details

Title Knobloch Syndrome-1: An Uncommon Cause for Genetic Focal Epilepsy

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) P10 - Poster Session 10 (8:00 AM-9:00 AM)

Poster/Presentation
Number 10-006

Objective To describe a rare case of Knobloch syndrome-1 presenting with focal epilepsy.

Background

Knobloch syndrome-1, an autosomal recessive disorder first described in 1971, is associated with the COL18A1 gene. Pathognomonic features include high myopia, vitreoretinal degeneration, and occipital encephalocele. Despite case descriptions in the literature focusing on ocular manifestations, this syndrome can be associated with polymicrogyria and other migrational abnormalities, leading to epilepsy and/or intellectual disability. Herein, we present a case of a young, well-educated woman with focal epilepsy, high myopia, and polymicrogyria on MRI found to have Knobloch syndrome-1.

Design/Methods Single case report with clinical, neuroimaging, and genetic correlation.

Results A 19-year-old Iraqi woman with congenital high myopia presented with new-onset focal impaired consciousness and focal-to-bilateral tonic-clonic seizures. She denied a family history of epilepsy; however, her paternal grandmother and two paternal cousins had congenital high myopia of unclear etiology. She was a developmentally normal, bright college student. MRI brain revealed extensive polymicrogyria bilaterally in the frontal lobes, post-central gyrus, and peri-sylvian cortex. EEG captured intermittent left temporal slowing. An Invitae genetic epilepsy panel revealed homozygosity for a pathogenic COL18A1 (c.2338C>T) variant. She was treated with lacosamide initially, with cenobamate later added for persistent seizures.

Conclusions Knobloch syndrome-1 is a rare clinically heterogenous disorder. COL18A1 is a collagen XVIII/endostatin gene highly expressed throughout the human eye. Pathogenic variations in this gene can also lead to abnormal neuronal migration. The scarce descriptions of patients with epilepsy and Knobloch syndrome-1 in the literature note intellectual disability. Our patient had a unique phenotype in that she was a high functioning college student, diagnosed later in life. She was also the first in her family line to exhibit seizures, with other family members only describing ocular manifestations. This case exemplifies the importance of a thorough history and examination, not overlooking ocular findings, in evaluating new-onset epilepsy.

Authors/Disclosures
Junaid M. Essa, DO PRESENTER	Dr. Essa has nothing to disclose.
Ashley L. Lefebvre, DO, PharmD (UF Health Jacksonville)	Dr. Lefebvre has nothing to disclose.
Katherine A. Zarroli, MD (University of Florida - Jacksonville)	Dr. Zarroli has nothing to disclose.

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