A Fast-Moving Inherited Macular Dystrophy
Beneath the retina runs a thin structural layer called Bruch's membrane, sitting between the retina and the blood supply that feeds it. In Sorsby fundus dystrophy, a faulty protein causes that layer to thicken abnormally, and the retina responds by sprouting new, fragile blood vessels to try to compensate — vessels that leak and bleed with very little provocation. It's this abnormal vessel growth, arriving decades earlier than it typically would with ordinary age-related disease, that makes Sorsby dystrophy one of the more aggressive conditions covered on this site.
For a Ghanaian patient in their thirties or forties whose central vision has dropped sharply over a matter of weeks rather than years, that speed itself is often the earliest clue pointing toward Sorsby dystrophy rather than a slower, more typical dystrophy.
Unlike most inherited macular conditions, Sorsby dystrophy can cause genuinely sudden or rapid central vision loss in one eye, with the second eye usually following within a few years. Distortion of straight lines and a rapidly expanding blurred patch in central vision are common presenting complaints, and a subtle difficulty adjusting to dim lighting sometimes shows up months, or even longer, before the more dramatic central symptoms appear.
TIMP3, the gene at fault here, ordinarily produces a protein tasked with keeping tissue turnover around Bruch's membrane properly balanced. Once that regulation breaks down, the membrane starts thickening in a way it shouldn't, and the retina reacts by pushing out new blood vessels through the weakened barrier — vessels that are structurally poor and prone to leaking almost as soon as they form. A single copy of the faulty gene, inherited from either parent, is enough on its own to bring on the condition.
The tell-tale sign on a routine fundus exam is a scatter of pale yellow-white deposits tracing the path of the retinal vessels — a pattern that, once seen, tends to stick in a specialist's memory. From there, imaging shifts toward hunting for active neovascular tissue specifically: OCT angiography, and fluorescein angiography where a clearer picture is needed, both aimed at establishing whether new vessels are currently leaking. TIMP3 genetic testing confirms the underlying cause, and because this condition can move quickly, we don't let that testing sit on a waiting list.
Whenever active leaking vessels are found, dealing with that immediate threat takes precedence over everything else on the treatment plan. Once the eye has settled and stabilised, we turn to regenerative stem cell therapy for patients who qualify, built around supporting the retina going forward, and we keep a tighter follow-up interval here than we would for the slower dystrophies, simply because Sorsby has a track record of moving fast when it moves at all.
It genuinely can, and that's actually one of the clues we look for. Sorsby dystrophy is known for behaving this way, unlike almost every other inherited macular condition, where change tends to unfold over years rather than weeks.
It happens, since the two can look strikingly similar on a scan once new vessels are involved. What separates them is largely the timeline — Sorsby shows up decades earlier — along with family history and a TIMP3 genetic test.
It's a genuine reason to move quickly, since untreated leaking vessels can cause additional vision loss in a short space of time. Our first step is always getting that specific problem under control before anything else.
Not inevitable, though the odds are real — this is a dominant condition, so a child of an affected parent has roughly a coin-flip chance of carrying the gene. How severely it shows up, if it does, tends to differ from person to person, and a genetic test can give your family a clearer answer.