Sequence Variants Found in Index Cases.

<p>RefSeq NG_008134.1, NM_004977.2, NP_004968.2, % reflects allele frequency.</p><p>*Variant Found in patient with p.Arg423His and sister.</p><p>**Known SNP rs35578310.</p

MRI of Patient with the p.Arg423His mutation.

<p>Cerebellar atrophy in a 48 year old female (H2591) with ataxia and the KCNC3^Arg423His mutation. Midsagittal T1-weighted MRI of the brain shows a small atrophic cerebellum with a normal appearing brainstem.</p

Clinical and mutation findings of p.Arg423His index patient and relatives.

<p>Nucleotide numbering for cDNA –based nomenclature uses 1+ as to the A of the ATG translation initiation codon in Genebank RefSeq NM_004977.2.</p><p>The initiation codon is codon 1. RefSeq NG_008134.1, NP_004968.2.</p

Mutation kinetics in <i>X. laevis</i> oocytes.

<p>p.Gly263Asp alters activation and deactivation kinetics in <i>X. laevis</i> oocytes. (<b>A</b>) p.Gly263Asp currents were evoked by stepping from −90 mV to voltages ranging from −90 mV to +70 mV in 10 mV increments. (<b>B</b>) Normalized isochronal tail current amplitudes have been plotted versus voltage for wild-type (▪, <i>n</i> = 84) and p.Gly263Asp (□, <i>n</i> = 8). (<b>C</b>) Activation time constant (τ_act) was plotted versus voltage. *Wild-type (▪, <i>n</i> = 36) and p.Gly263Asp (□, <i>n</i> = 8) values differed significantly , p<0.05. Inset: Wild-type (solid) and p.Gly263Asp (dotted) currents were evoked at 0 mV, scaled and overlaid. (<b>D</b>) Deactivation time constant (τ_deact) was plotted versus repolarization voltage. Wild-type (▪, <i>n</i> = 10) and p.Gly263Asp (□, <i>n</i> = 8) values differed significantly, p<0.05. Inset: Wild-type (solid) and p.Gly263Asp (dotted) tail currents were recorded at −60 mV, scaled and overlaid.</p