Color Fundus Photographs
(A) Color fundus photographs of patient IV:3 in family 1.
(B) Color fundus photographs, fundus autofluorescence, and Goldmann kinetic perimetry of patient II:2 in family 2. Goldmann perimetry isopters for targets III4a, II4a, and I4a are shown.

Region of Autozygosity Mapping and Analysis Of Gene Structure for the TRPM1 Gene
(A) Region of autozygosity for family 1 on chromosome 15q, of 15.9 Mb and 280 SNPs flanked by rs2090622 and rs10518928. A total of 106 Unigene clusters were found in the region. Only the partial region is shown in this figure.
(B) Results of RACE experiments for TRPM1 transcripts in human retina and skin. One transcript with a 201 bp 5′ extension of the published exon 1 was found in both skin and retinal tissue. An alternative and previously unreported 5′ exon of 275 bp, denoted here as exon 1a, was detected in retina approximately 84 Kb upstream of the published exon 2, spliced directly to exon 2 (omitting exon 1). Approximate physical distances are shown.
(C) The start codon of TRPM1 in the published sequence (NM_002420.4) is shown (rs4779816), with other likely translation start sites in the different transcripts.

Pedigrees from Evaluated Families
Electropherograms of DNA sequence surrounding likely disease-causing variants are shown beneath each pedigree.

International-Standard Full-Field ERGs and Pattern ERGs from One Eye of Three Affected Individuals and One Control Subject
Top to bottom: patient IV:3 in family 1, patient II:2 in family 2, patient II:1 in family 3, control subject. Columns 1 and 2 show dark-adapted ERGs for flash intensities of 0.01 and 11.5 cd.s/m2 (columns 1 and 2). Columns 3 and 4 show light-adapted ERGs for a flash intensity of 3.0 cd.s/m2 presented at 30Hz (column 3) or 2Hz (column 4). Column 5 shows pattern ERGs (PERGs) recorded to an alternating checkerboard (check size 0.75 degrees, 4 reversals per s). Column 6 shows additional ON-OFF ERGs that use an orange stimulus (560 cd/m2, duration 200 ms) superimposed on a green background (150 cd/m2). Column 7 shows S-cone ERGs that use a blue stimulus (445 nm, 80 cd/m2) on an orange background (620 nm, 560 cd/m2). Dim-flash rod ERGs are undetectable (column 1). Bright-flash, dark-adapted ERGs are profoundly electronegative, with a b-wave of much lower amplitude than the borderline or minimally reduced a-wave. Photopic 30 Hz flicker ERGs show a slightly flattened trough and normal (patient II:1 in family 3) to marginally delayed peak times. Photopic single-flash ERGs show a broadened a-wave trough and a reduced-amplitude, sharply-rising b-wave lacking photopic oscillatory potentials. PERGs are undetectable, in keeping with macular involvement. Photopic ON-OFF ERGs show a profoundly reduced ON b-wave with relative sparing of the OFF response. S-cone ERGs show loss of the S-cone-specific component (the latter of the two peaks in the control subject), with some reduction in the amplitude of the L-M cone peak (the earlier of the two peaks in the normal). The findings therefore suggest ON pathway dysfunction in rods and all cone types.

Experiments Examining TRPM1 RNA and 5′ RACE Experiments
(A) The integrity of RNA samples from human retina and skin were assessed with the Experion system (Bio-Rad, Hercules, CA, USA). The traces show similar peaks and ratios for 28S and 18S RNA molecules (vertical axis, fluorescence intensity; horizontal axis, migration time), suggesting low degradation and comparable quality from both tissues. The right panel shows the data as a computer-generated gel image.
(B) 2% agarose gel of DNA fragments generated from 5′ RACE experiments from the RNA assessed in Figure 5A (see main text and Table S2). With the use of a primer complimentary to a 5′ adapter oligonucleotide (Invitrogen, Carlsbad, CA, USA) and a gene-specific primer complimentary to exon 3, two main bands were produced, consistent with the published sequence (smaller band, 200 bp), as well as a mixture of the previously unreported 5′ exon 1a (∼475 bp) and as the 5' extension of exon 1 (475 bp), also previously unreported. The larger band was predominant in the retina, and the smaller was predominant in skin.
(C) After the generation of sequence from multiple clones of the 5′ RACE products (see main text), RT-PCR experiments were performed on skin and retina RNA and separated on 2% agarose, with the use of primers shown in the schematic below for determination of the presence of the various transcripts in the two tissues. The skin consistently failed to amplify for two different primers in exon 1a when used with reverse primers from exon 3 and 6. RT-PCR from comparable amounts of RNA gave less-dense bands than that in the retina for all other primer combinations. Lanes indicate the following: lane 0, ladder (subsequent lanes are paired reactions from retina and skin); lanes 1 and 2, 1aF and 3R; lanes 3 and 4, 1aF1 and 6R; lanes 5 and 6, 1F1 and 3R; lanes 7 and 8, 1F2 and 3R; lanes 9 and 10, 1F1 and 6R; lane 11, PCR with 1F1 and 6R from genomic DNA control; lane 12, same as 11 with water as control.