Expanding the epilepsy spectrum in primary coenzyme Q10 deficiency with COQ4 variants - Case series and literature review.

Objective

To characterize the epileptic spectrum associated with COQ4 variants through three newly identified patients and literature review.

Methods

We retrospectively collected clinical data from three patients with COQ4 variants diagnosed at Chang Gung Memorial Hospital, Linkou Branch, between November 2021 and December 2023. A literature review identified 66 previously reported patients with COQ4 variants. Clinical presentation, genotype, seizure characteristics, epilepsy syndromes, electroencephalographic findings, and treatment information were extracted when available.

Results

Among the 69 cases with COQ4 variants in this study and previously reported cases, 48 (70%) had seizure presentations, including generalized-onset seizures, focal-onset seizures, epileptic spasms, and seizures of unknown onset. Here, we report three patients with COQ4 variants presenting with early infantile developmental and epileptic encephalopathy (EIDEE), the first reported case of epilepsy of infancy with migrating focal seizures (EIMFS) in a patient with COQ4 variants, and infantile epileptic spasms syndrome (IESS) with a favorable documented response to corticosteroid therapy, further expanding the epileptic phenotypic spectrum of COQ4 variants.

Significance

Our findings broaden the epileptic spectrum associated with COQ4 variants and highlight the importance of early genetic testing in infants with developmental and epileptic encephalopathies, EIMFS, or IESS. The favorable corticosteroid response observed in our patient with IESS and COQ4 variants may have therapeutic implications and warrants further investigation.