Impaired Color Recognition in HCN1 Epilepsy: A Single Case Report.

2022-03-10

Mckenzie, Chaseley E

Ho, Chen-Jui

Forster, Ian C

Soh, Ming S

Phillips, A Marie

Chang, Ying-Chao

Scheffer, Ingrid E

Reid, Christopher A

Tsai, Meng-Han

HCN1

color vision

developmental and epileptic encephalopathy

epilepsy

missense

Journal Article

0000-0002-2311-2174

0000-0002-1457-8028

0000-0003-3087-9952

0000-0002-3638-2077

10.3389/fneur.2022.834252

Variants in HCN1 are associated with a range of epilepsy syndromes including developmental and epileptic encephalopathies. Here we describe a child harboring a novel de novo HCN1 variant, E246A, in a child with epilepsy and mild developmental delay. By parental report, the child had difficulty in discriminating between colors implicating a visual deficit. This interesting observation may relate to the high expression of HCN1 channels in rod and cone photoreceptors where they play an integral role in shaping the light response. Functional analysis of the HCN1 E246A variant revealed a right shift in the voltage dependence of activation and slowing of the rates of activation and deactivation. The changes in the biophysical properties are consistent with a gain-of-function supporting the role of HCN1 E246A in disease causation. This case suggests that visual function, including color discrimination, should be carefully monitored in patients with diseases due to HCN1 pathogenic variants.

link

Frontiers in neurology 2022; 13: 834252

Frontiers in neurology

1664-2295