Table 1. Summary of disease-causing mechanisms of BEST1 P274R and I201T mutations.

	Mechanism		System	P274R	I201T
Phenotype	-		Patient	Severe	Mild
Function	I	CaC current	RPE	Null	Small
		Ca2+ sensitivity	RPE	N/A	Normal
		CaC current of BEST1	HEK293	Null	Small
	N	BEST1 expression	RPE	Normal	Normal
		Membrane localization	RPE	Diminished	Normal
	i	Unitary current	KpBest	Null	Small
Structure	-		KpBest crystal + human model	Disrupted	Slightly altered

I = N × P_o× i. I, whole-cell current amplitude; N, number of surface channels; P_o, channel open probability; i, unitary current.