Covered on Genetics Home Reference: cone-rod dystrophyretinitis pigmentosaFrom NCBI Gene: Stargardt disease 4Cone-rod dystrophy 12Bull's eye macular dystrophyRetinitis pigmentosa 41From UniProt: Retinitis pigmentosa 41 (RP41): A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well. [MIM:612095] Retinal macular dystrophy 2 (MCDR2): A bull's-eye macular dystrophy characterized by bilateral annular atrophy of retinal pigment epithelium at the macula. [MIM:608051] Cone-rod dystrophy 12 (CORD12): An inherited retinal dystrophy characterized by retinal pigment deposits visible on fundus examination, predominantly in the macular region, and initial loss of cone photoreceptors followed by rod degeneration. This leads to decreased visual acuity and sensitivity in the central visual field, followed by loss of peripheral vision. Severe loss of vision occurs earlier than in retinitis pigmentosa. [MIM:612657] Stargardt disease 4 (STGD4): A common hereditary macular degeneration. It is characterized by decreased central vision, atrophy of the macula and underlying retinal pigment epithelium, and frequent presence of prominent flecks in the posterior pole of the retina. [MIM:603786]

     From NCBI Gene: This gene encodes a pentaspan transmembrane glycoprotein. The protein localizes to membrane protrusions and is often expressed on adult stem cells, where it is thought to function in maintaining stem cell properties by suppressing differentiation. Mutations in this gene have been shown to result in retinitis pigmentosa and Stargardt disease. Expression of this gene is also associated with several types of cancer. This gene is expressed from at least five alternative promoters that are expressed in a tissue-dependent manner. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2009] From UniProt: May play a role in cell differentiation, proliferation and apoptosis (PubMed:24556617). Binds cholesterol in cholesterol-containing plasma membrane microdomains and may play a role in the organization of the apical plasma membrane in epithelial cells. During early retinal development acts as a key regulator of disk morphogenesis. Involved in regulation of MAPK and Akt signaling pathways. In neuroblastoma cells suppresses cell differentiation such as neurite outgrowth in a RET-dependent manner (PubMed:20818439).

The following transcription factors affect gene expression:

• p53
• C/EBPbeta

Tissue specificity:

Isoform 1 is selectively expressed on CD34 hematopoietic stem and progenitor cells in adult and fetal bone marrow, fetal liver, cord blood and adult peripheral blood. Isoform 1 is not detected on other blood cells. Isoform 1 is also expressed in a number of non-lymphoid tissues including retina, pancreas, placenta, kidney, liver, lung, brain and heart. Found in saliva within small membrane particles. Isoform 2 is predominantly expressed in fetal liver, skeletal muscle, kidney, and heart as well as adult pancreas, kidney, liver, lung, and placenta. Isoform 2 is highly expressed in fetal liver, low in bone marrow, and barely detectable in peripheral blood. Isoform 2 is expressed on hematopoietic stem cells and in epidermal basal cells (at protein level). Expressed in adult retina by rod and cone photoreceptor cells (at protein level).

Molecular Function:

• Actinin Binding
• Cadherin Binding

Biological Processes:

• Retina Layer Formation
• Photoreceptor Cell Maintenance
• Retina Morphogenesis In Camera-Type Eye
• Camera-Type Eye Photoreceptor Cell Differentiation
• Glomerular Visceral Epithelial Cell Differentiation
• Glomerular Parietal Epithelial Cell Differentiation
• Positive Regulation Of Nephron Tubule Epithelial Cell Differentiation