Case#: Male, Family #1, Patient #1, II:1 in pedigree

DiseaseAssertion: Hypomorphic Stargardt disease

FamilyInfo: Paternal female cousin also has hypomorphic Stargardt disease and both of them carry the complex allele p.[L541P; A1038V] and p.N1868I. Additionally, their paternal aunt was diagnosed with Stargardt disease. This information can be found on Fig.1.

CasePresentingHPOs: HP:0000622, HP:0025010

CaseHPOFreeText: This proband developed blurred vision at age 30. The foveal atrophy affects the left eye. In the first visit at 33.9 years old patient presents with 20/25-3 Snellen VA OD, 20/70-2 Snellen VA OS, 0.16 LogMAR VA OD, 0.58 LogMAR VA OS, and stage 1. In the last visit at age 40.7, the patient had a 20/40-2 Snellen VA OD, a 10/80-1 Snellen VA OS, 0.34 LogMAR VA OD, 0.92 LogMAR VA OS, and was now in stage 2. In a Goldmann Visual Field test, they found central scotomas II4e; mild-moderate constriction II2e.

CaseNotHPOs: N/a

CaseNotHPOFreeText: The proband maintained some relative foveolar sparing in his right eye and had a BCVAs of 20/4022 (test done at 40 years old).

Genotyping Method: Genetic testing was performed at Columbia University. It was not stated which method this proband underwent, so the genetic testing could have been one of the following: "The entire ABCA4 gene locus was sequenced in 17 patients; the ABCA4 gene, including all exons and intron/exon boundaries were sequenced in 4 patients. In the remaining 6 cases representing family members, only targeted testing was performed."

PreviouslyPublished: N/a

**Variant: ** M1) NM_000350.3(ABCA4):c.5603A>T M2) NM_000350.3(ABCA4):c.1622T>C (p.Leu541Pro)

ClinVar: M1) 99390 M2) 99067

CAID: N/a

gnomAD: M1) The highest minor allele frequency was 0.05787 (https://www.ncbi.nlm.nih.gov/clinvar/variation/99390/) M2) The highest minor allele frequency was 0.00017 (https://www.ncbi.nlm.nih.gov/clinvar/variation/99067/)

SupplementalData: Table 1. provided patient information for those with p.N1868I ABCA4 Stargardt disease and the associated ABCA4 mutations. Fig.1. shows the pedigrees of the families. Fig.3. shows Macular SD-OCT line profiles for some of the patients. Table 2. describes the onset/symptoms of the patients with p.N1868I ABCA4 Stargardt Disease. Table 3. shows Visual Acuity and Stage at Baseline and Most Recent Follow-up in Patients With p.N1868I ABCA4 Stargardt Disease. Fig.4. shows BCVA better eye vs Duration since first examination for the patients. Table 4. shows clinical findings in the patients.