NKAIN2 and Huntington disease: Similar to iAstro clusters 1 and 2 that had large proportion of HD iAstros, striatal cluster 5 had the highest expression of sodium, potassium, or calcium ion-binding genes, like Adgrv1, Nkain2, and Cacnb2, except for the potassium channel, Kcnd2, which was most highly expressed in striatal clusters 1 and 2.