S2 File: This file contains the following sub-files: Figures A-C, Tables A-E and the references of the detected mutations in Tables A-E. Figure A shows the overall coverage of genes in the panel. Figures B and C show the genes that doesn’t reach 100% and 99%, respectively. Table A shows the variant numbers detected by NGS of 68 samples have previously tested by Sanger sequencing before. Table B shows the results of all 68 samples previously screened by Sanger sequencing. Table C shows the Z-score results for CNV detecting of family P041 and P048. Table D: Statistics of targeted NGS in 99 RP patients, shows the depth, coverage and variant numbers detected in 99 RP patients. Table E shows the mutations identified in 61 out of 99 RP patients.(RAR)pone.0185237.s002.rar (1.9M)GUID: D12AF020-8D31-4449-ACC9-879865E75832

Eighty-four unrelated STGD1 patients were found to carry two or more disease-causing ABCA4 mutations, and cosegregation analyses were performed in 54 (64.3%). (See Supplementary Table S3 for a summary of clinical phenotype of STGD1 patients). The mean disease onset age of the patients was 13.1 years (range, 2–44 years), and half of these patients experienced their symptoms of visual impairment in their first decade. We classified the patients into three groups by their disease onset age. For the patients in the first group, whose disease onset ages were between 1 and 10 years, the fraction (45.3%, 19/42) of patients carrying compound heterozygous or homozygous deleterious mutations (nonsense, frameshift insertion or deletion, or splicing mutations) or complex alleles was much higher than those observed for the patients in the group 2 (24.1%, 7/29) and group 3 (15.4%, 2/13), whose disease onset ages were from 11 to 20 years or older than 20 years, respectively. In contrast, the percentage of patients carrying compound heterozygous or homozygous missense mutations was higher in group 3 than in group 1 or group 2 (Table 2). The most common mutation (p.Y808X) was detected in 12 patients, and all were heterozygous compound with missense (6 patients), splicing (1 patient), and insertion or deletion (5 patients) mutations. The two most frequent missense mutations (p.F2188S and p.N965S) were identified as heterozygous. In 84 patients, 9 patients carried complex mutations, and 4 of those 9 patients carried a common complex allele p.E328V/p.E1036K. All these patients had early onset age and relatively severe visual acuity defects. One patient (010222) also carried three heterozygous mutations (p.E328, p.E1036K, and p.R1843W); however, he did not harbor the common complex allele p.E328V/p.E1036K, as only p.E1036K was detected in his son in the subsequent cosegregation analysis. Compared to the four patients carrying the common complex alleles (p.E328V/p.E1036K), patient 010221 had a late onset age (44 years old).

We identified 255 patients (87.9 %) harboring biallelic ABCA4 variants, 27 probands (9.3 %) with two or three variants but lacking familial segregation analysis, and eight patients (2.8 %) with monoallelic ABCA4 variants (Supplemental Table S4). We detected 268 distinct ABCA4 variants, consisting of 114 missense, 35 nonsense, 34 frameshift deletion or insertion, 31 canonical splice variants, 13 noncanonical splice site variants, 9 in-frame deletion or insertion, 9 DIVs, 4 structural variations, and 19 complex variants (Fig. 2).

We identified 255 patients (87.9 %) harboring biallelic ABCA4 variants, 27 probands (9.3 %) with two or three variants but lacking familial segregation analysis, and eight patients (2.8 %) with monoallelic ABCA4 variants (Supplemental Table S4). We detected 268 distinct ABCA4 variants, consisting of 114 missense, 35 nonsense, 34 frameshift deletion or insertion, 31 canonical splice variants, 13 noncanonical splice site variants, 9 in-frame deletion or insertion, 9 DIVs, 4 structural variations, and 19 complex variants (Fig. 2).

We identified 255 patients (87.9 %) harboring biallelic ABCA4 variants, 27 probands (9.3 %) with two or three variants but lacking familial segregation analysis, and eight patients (2.8 %) with monoallelic ABCA4 variants (Supplemental Table S4). We detected 268 distinct ABCA4 variants, consisting of 114 missense, 35 nonsense, 34 frameshift deletion or insertion, 31 canonical splice variants, 13 noncanonical splice site variants, 9 in-frame deletion or insertion, 9 DIVs, 4 structural variations, and 19 complex variants (Fig. 2).

Table_5.xls (35K)GUID: F0FBE3EF-4607-46DE-9804-35E6F0FB6695

P023 ABCA4 20 c.3035_3037delACA p.Asn1012Ile ATP-binding domain novel deletion – DCABCA4 24 c.3547G>T p.Gly1183Cys – reported – – –ABCA4 46 c.6289C>T p.Pro2097Ser ATP-binding domain novel missense probablydamagingDC

In this study, we summarized the phenotypic and genotypic characteristics of 129 Chinese patients with ABCA4-RD.

STGD in 48 patients (55%) was explained by recessive ABCA4 mutations (supplemental table S2). Only 22 patients could be solved using previously known STGD causing mutations. However, we identified 35 novel mutations in ABCA4 contributing to the diagnosis of 25 STGD patients. This contained 10 novel mutations leading to amino acid substitutions already known to cause disease and mutations known to cause diseases other than STGD. In addition, we identified 13 novel nonsense mutations. The remaining 12 novel mutations are well justified, and novel mutations were either completely absent or extremely rare in controls.

Introducing a comprehensive genetic testing strategy by combining single gene Sanger sequencing, next-generation sequencing (NGS) including whole exome sequencing (WES), and a specific hereditary eye disease enrichment panel (HEDEP) sequencing, to identify the disease-causing variants of 800 Chinese probands affected with non-syndromic IRDs.

A cohort of 12 unrelated STGD families diagnosed on the basis of clinical manifestations underwent analysis by targeted exome or whole-exome sequencing. Bioinformatics analysis, Sanger sequencing, and cosegregation analysis of available family members were used to validate sequencing data and confirm the presence of disease-causing genes. Results: Using targeted exome and whole-exome sequencing, we found that eight families had disease-causing variants in the ABCA4 gene, one family had only one heterozygous variant in the ABCA4 gene, and the remaining three families have not been identified with any disease-causing variants for STGD. We identified 15 variants in the ABCA4 gene; of these, five variants have not been previously described for STGD.

Table S2. ABCA4 variant categorization:

Supplementary Materials

We identified 255 patients (87.9 %) harboring biallelic ABCA4 variants, 27 probands (9.3 %) with two or three variants but lacking familial segregation analysis, and eight patients (2.8 %) with monoallelic ABCA4 variants (Supplemental Table S4). We detected 268 distinct ABCA4 variants, consisting of 114 missense, 35 nonsense, 34 frameshift deletion or insertion, 31 canonical splice variants, 13 noncanonical splice site variants, 9 in-frame deletion or insertion, 9 DIVs, 4 structural variations, and 19 complex variants (Fig. 2).

We identified 255 patients (87.9 %) harboring biallelic ABCA4 variants, 27 probands (9.3 %) with two or three variants but lacking familial segregation analysis, and eight patients (2.8 %) with monoallelic ABCA4 variants (Supplemental Table S4). We detected 268 distinct ABCA4 variants, consisting of 114 missense, 35 nonsense, 34 frameshift deletion or insertion, 31 canonical splice variants, 13 noncanonical splice site variants, 9 in-frame deletion or insertion, 9 DIVs, 4 structural variations, and 19 complex variants (Fig. 2).

Peripheral venous blood was obtained from 24 clinically diagnosed Korean STGD patients, followed by extraction of genomic DNAs. Using exome sequencing we investigated gene mutations for the adenosine triphosphate-binding cassette, subfamily A, member 4 (ABCA4) elongation of very-long-chain fatty acids 4 (ELOVL4), and prominin 1 (PROM1), and confirmed gene mutations by the direct sequencing of polymerase chain reaction products.

Screening of reported pathogenic variants in ABCA4 for Stargardt (STGD) The disease prevalence of STGD is estimated as 1 in 10000 individuals4. It has been estimated that about 70% of STGD patients carry variants in ABCA45. Therefore, this represents the scenario of a recessive disease with a relatively homogeneous genetic cause. We screened 945 reported pathogenic variants in ABCA4 genes collected in HGMD. Among them, 11 variants are likely benign, as their population AF in is higher than 0.7% (1/20000‾‾‾‾‾‾‾‾√)<math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="M11"><mrow><mrow><mo>(</mo><mrow><msqrt><mrow><mn>1</mn><mo>/</mo><mn>20000</mn></mrow></msqrt></mrow><mo>)</mo></mrow></mrow></math>, the cutoff based on STGD disease prevalence, therefore were excluded from further analysis. The remaining 934 variants were subjected to our test model. As a result, 26 variants with the AF in the range of 0.46% to 0.03% were identified as likely benign (Binomial test1, Bonferroni correction p-value ≤ 0.05/934 and test2 Bonferroni correction p-value > 0.05/934) (Figure 3A).