Case#: 47-year-old female, sibling of patient 1.

DiseaseAssertion: Discordant STGD phenotype

FamilyInfo: The mother was found to harbour p.L541V/p.A1038V, and the father carried the p.R811C mutation; both of whom were asymptomatic with normal retinal examination (Fig. 1). ABCA4 screening detected three variants: two variants p.L541V and p.A1038V – commonly co-inherited in a complex allele in STGD (Maugeri et al. 2000) – and a third novel variant p.R881C (Fig. 1). Patient 1 had all three variants

CasePresentingHPOs: HP:0007401, HP:0025010, HP:0011507

CasePhenotypeFreeText: Patient 2 is the 47-year-old sister of patient 1. At initial examination in 1994, she reported a central scotoma. VA was 6/9 in both eyes with bilateral subtle foveal atrophy and perifoveal yellowish-white flecks (Fig. 1). By 2003, foveal atrophy had progressed with more perifoveal flecks (Fig. 1). In 2012, her VA was 6/12 bilaterally, but fundus findings remained stable (Fig. 1). AF imaging demonstrated a mottled signal within the central macula, optical coherence tomography showed outer retinal disruption confined to the central macula

CaseNotHPOs: N/A

CaseNotPhenotypeFreeText: N/A

CasePreviousTesting: The article mentions ABCA4 screen but does not go into detail. However, it does say,”(patient 2) harboured the complex allele (p.L541V/p.A1038V)”

GenotypingMethod: Again only mentioned ABCA4 screening without going into detail.

Variant: NM_000350.3:c.1621C>G and NM_000350.3(ABCA4):c.3113C>T

LegacyVariant: c.1621C>G (p.Leu541Val) and c.3113C>T(p.Ala1038Val)

CAID: CA341280463 and CA119135

gnomeAD: chr1-94063251-G-C and chr1-94043413-G-A

PreviouslyPublished: N/A

AdditionalInfo: Figure 1 provides information about the imaging of patients’ eyes that helps determine phenotype.