ADIPOR1

ADIPOR1 stands for adiponectin receptor 1. The protein it makes sits on the surface of cells and receives signals from adiponectin, a hormone that influences fatty acid breakdown and insulin sensitivity. When adiponectin binds to the receptor, it switches on an internal signaling pathway (AMP-activated kinase) that helps cells manage energy and fats. In the eye, mouse studies have found the receptor in the photoreceptors (the light-sensing cells) and in the retinal pigment epithelium, a supportive layer beneath them. In those studies, the receptor acted like a switch that controls how much DHA the retina takes up and keeps, which appears important for keeping photoreceptors healthy.

The human evidence linking ADIPOR1 to inherited retinal disease is limited to a small number of reports. In one report, researchers used whole-genome analysis and found a change in both copies of ADIPOR1 in a person with a syndromic form of retinitis pigmentosa, a disease that gradually damages the retina. In a separate report, a single change in one copy of ADIPOR1 was found to track with disease across a large Chinese family who had non-syndromic retinitis pigmentosa, with features such as night blindness, narrowing side vision, and reduced sharpness of vision. A separate study reported that a common variation within ADIPOR1 was statistically associated with advanced age-related macular degeneration in a Finnish population, though this is a risk-association finding rather than proof that the gene causes that disease. In mice lacking a working copy of the gene, photoreceptors did not function normally, electrical responses of the retina were reduced, and the cells gradually degenerated.

It is well established that ADIPOR1 makes a receptor for adiponectin and helps regulate fat and sugar metabolism throughout the body. Laboratory work in mice consistently shows that when ADIPOR1 is missing, the retina loses DHA and photoreceptors deteriorate, which points to a genuine role for this gene in retinal health. A handful of human reports have identified ADIPOR1 changes in people with retinitis pigmentosa, which is why it is treated as a candidate cause of inherited retinal disease.

Because the human evidence rests on very few reports, it is not yet certain how often, or by what inheritance pattern, ADIPOR1 causes retinal disease in people. The two published human cases actually describe different patterns: one involved changes in both gene copies with additional non-eye features, while the other described a single-copy change passed down through a family with retinal disease alone. The reported link to age-related macular degeneration came from one population study and describes a modest statistical risk, not a direct cause. ADIPOR1 is not currently included in GeneReviews, the standard clinical reference for well-established retinal disease genes, which reflects how limited the human evidence still is. Whether findings from mouse and cell studies will translate into human disease and treatment remains an open question.

No approved therapy currently targets ADIPOR1-related retinal disease. Much of the ongoing research explores the gene's role in fatty acid handling in the retina, building on findings that ADIPOR1 helps supply DHA to photoreceptors. In mice missing ADIPOR1, researchers found a harmful buildup of a fat molecule called ceramide, and treating the animals with ceramide-lowering drugs improved photoreceptor (definition: A light-sensing cell in the retina. Rods (used for night and peripheral vision) and cones (used for color and detail) are the two types.) survival and some measures of vision. These are early laboratory findings in animals and are not treatments available to patients. Separate mouse and cell studies have also examined adiponectin-related molecules in the context of age-related macular degeneration, but these too remain preclinical (definition: Research done in cells or animals, before a treatment is considered ready to be studied in people.).

• An ADIPOR1 change found in a person with syndromic retinitis pigmentosa

  Single human case report with supporting laboratory work.

  What was found:

  They identified a change in both copies of ADIPOR1 in a person whose features resembled those seen in ADIPOR1-deficient mice, including retinal disease and non-eye findings.

  Why it matters:

  This was among the first reports proposing ADIPOR1 as a cause of retinal disease in humans.

  Limitation: A single case cannot establish how commonly or reliably ADIPOR1 causes disease.

• An ADIPOR1 change tracked with retinitis pigmentosa in a large family

  Single-family human study with animal-model support.

  What was found:

  A single-copy ADIPOR1 change (p.Y310C) followed the disease through the family, and reducing the gene in zebrafish preferentially harmed rod photoreceptors, a hallmark of the disease.

  Why it matters:

  It suggested ADIPOR1 could cause non-syndromic dominant retinitis pigmentosa, a different pattern from the syndromic report.

  Limitation: Findings come from one family, and the differing inheritance patterns across reports remain unexplained.

• ADIPOR1 helps photoreceptors conserve DHA

  Preclinical animal and cell research.

  What was found:

  Mice without ADIPOR1 had reduced retinal DHA, weakened electrical responses, and progressive photoreceptor loss; boosting the receptor increased DHA uptake in cells.

  Why it matters:

  It identified a biological mechanism by which ADIPOR1 loss could damage the retina.

  Limitation: Results are from mice and cultured cells and may not directly predict human disease.

• Lowering ceramide protected photoreceptors in ADIPOR1-deficient mice

  Preclinical animal research (proof of concept).

  What was found:

  ADIPOR1-deficient retinas accumulated ceramide, and drug treatment that lowered ceramide improved photoreceptor survival and some vision measures.

  Why it matters:

  It offers a possible therapeutic direction for ADIPOR1-related retinal disease.

  Limitation: This is an early animal study, not a treatment available or proven in people.

• A common ADIPOR1 variant and age-related macular degeneration

  Human association study.

  What was found:

  One common variation within ADIPOR1 showed a modest statistical association with advanced disease.

  Why it matters:

  It raised ADIPOR1 as a possible risk factor for age-related macular degeneration in that population.

  Limitation: The finding was modest, from a single population, and reflects risk rather than cause.

One of the two published human reports described a syndromic form, meaning the person had features beyond the eyes alongside retinal disease, so families may want to ask a clinician whether any non-eye monitoring is appropriate in their specific case. Because the two reports differed in how the gene change was inherited, a genetic counselor can best explain what a particular ADIPOR1 result may mean for relatives. Otherwise, the general guidance shown on every gene page applies here.

• Given that ADIPOR1 is a candidate rather than an established gene, how confident are we that it explains the retinal findings in my case?
• Was the specific ADIPOR1 variant found in one copy or both copies, and what does that suggest about how it might have been inherited?
• Would testing other family members help confirm whether this variant is meaningful?
• One published human case had features beyond the eyes — are there any non-eye findings that would be worth monitoring in my situation?
• Is any additional or repeat genetic testing recommended to look for other possible causes?
• How might this result affect how my vision is monitored over time?

If ADIPOR1 has appeared in your genetic results, discussing it with a retinal specialist or genetic counselor can help clarify what the finding means given how limited the current evidence is. Because a candidate finding may need additional confirmation, it can be useful to ask whether the specific variant has been seen before and whether other family members' testing would help interpret it. RP Hope's genetic testing resources explain what testing and counseling involve and what questions to bring.