Table 2.
Recessive Retinitis Pigmentosa genes, localizations and functions
| Gene | Location | Function |
|---|---|---|
| ABCA4 | 1p22.1 | ATP binding cassette subfamily A member 4; Photoreceptor-specific ATP-binding cassette (ABC) transporter with N-retinylidene-PE as a substrate. |
| AGBL5 | 2p23.3 | ATP/GTP binding protein like 5; Metallocarboxypeptidase that mediates protein deglutamylation; can remove glutamate residues from both carboxyl termini and side chains of protein substrates. |
| ARL6 | 3q11.2 | ADP ribosylation factor like GTPase 6; Involved in membrane protein trafficking at the base of the cilium. |
| ARL2BP | 16q13.3 | ADP ribosylation factor like GTPase 2 binding protein; Binds to ARL2.GTP with high affinity. Role in nuclear translocation, retention and transcriptional activity of STAT3. |
| BBS1 | 11q13.2 | Bardet-Biedl syndrome 1 protein; Required for BBSome complex assembly, its ciliary localization and ciliogenesis. |
| BBS2 | 16q13 | Bardet-Biedl syndrome 2 protein; Required for BBSome complex assembly, its ciliary localization and ciliogenesis. |
| BEST1 | 11q12.3 | Bestrophin 1; Forms calcium-sensitive chloride channels; highly permeable to bicarbonate. |
| C2orf71 | 2p23.2 | Chromosome 2 open reading frame 71; Photoreceptor cilia protein connecting inner and outer segments. |
| C8orf37 | 8q22.1 | Chromosome 8 Open Reading Frame 37; Co-localizes with polyglutamylated tubulin at the base of the primary cilium in RPE cells. |
| CERKL | 2q31.3 | Ceramide kinase-like protein; has no detectable ceramide-kinase activity; protects cells from apoptosis in oxidative stress. |
| CLRN1 | 3q25.1 | Clarin 1; A role in excitatory ribbon synapse junctions between hair cells and cochlear ganglion cells and possibly in analogous synapses in retina. |
| CNGA1 | 4p12 | Cyclic nucleotide gated channel alpha 1; Rod cGMP-gated channel alpha subunit; Forms cGMP-gated cation channel for depolarization of rod photoreceptors. |
| CNGB1 | 16q21 | Cyclic nucleotide gated channel beta 1; Rod cGMP-gated channel beta subunit; Forms cGMP-gated cation channel for depolarization of rod photoreceptors. |
| CRB1 | 1q31.3 | Crumbs 1; Plays a role in photoreceptor morphogenesis in the retina. May maintain cell polarization and adhesion. |
| CYP4V2 | 4q35.1 | Cytochrome P450 family 4 subfamily V member 2; Involved in fatty acid and steroid metabolism in the eye. |
| DHDDS | 1p36.11 | Dehydrodolichyl Diphosphate Synthase Subunit; forms the dehydrodolichyl diphosphate synthase (DDS) complex, an essential component of the dolichol monophosphate (Dol-P) biosynthetic machinery |
| DHX38 | 16q22.2 | DEAH-Box Helicase 38; Unknown function; probable ATP-binding RNA helicase involved in pre-mRNA splicing. |
| EMC1 | 1p36.13 | ER membrane protein complex subunit 1; Unknown function. |
| EYS | 6q12 | Eyes Shut Homolog (Drosophila); An extracellular matrix protein, one of the largest human genes at > 2mb. Possibly involved in stability of photoreceptor ciliary axonemes. |
| FAM161A | 2p15 | Family with sequence similarity 161 member A; Ciliary protein and a member of the Golgi-centrosomal interactome; involved in development of retinal progenitors. |
| GNAT1 | 3p21.31 | G Protein Subunit Alpha Transducin 1; α subunit of the heterotrimeric G-protein transducing; stimulates the coupling of rhodopsin and cGMP-phoshodiesterase. |
| GPR125/ADGRA3 | 4p15.2 | Adhesion G protein-coupled receptor A3/G protein-coupled receptor 125; Involved in signal trasduction. |
| HGSNAT | 8p11.21 | Heparan-alpha-glucosaminide N-acetyltransferase; Lysosomal acetyltransferase that catalyzes transmembrane acetylation of the terminal glucosamine residues of heparan sulfate, prior to hydrolysis by α-N-acetylglucosaminidase. |
| IDH3B | 20p13 | Isocitrate Dehydrogenase 3 (NAD(+)) Beta; catalyzes the oxidation of isocitrate to alpha-ketoglutarate in the citric acid cycle. |
| IFT140 | 16p13.3 | Intraflagellar transport 140; Involved in ciliogenesis, cilia maintenance and retrograde ciliary transport. |
| IFT172 | 2p23.3 | Intraflagellar transport 172; Involved in formation and maintenance of cilia. |
| IMPG2 | 3q12.3 | Interphotoreceptor matrix proteoglycan 2; Involved in organization of interphotoreceptor matrix. |
| KIAA1549 | 7q34 | KIAA1549 protein; Unknown function. |
| KIZ | 20p11.23 | Kizuna centrosomal protein; Localizes to centrosomes, strengthening and stabilizing the pericentriolar region prior to spindle formation. |
| LRAT | 4q32.1 | Lecithin retinol acyltransferase; Transfers the acyl group from phosphatidylcholine to all-trans retinol, producing all-trans retinyl esters. |
| MAK | 6p24.2 | Male germ-cell associated kinase; Unknown function. |
| MERTK | 2q13 | C-mer proto-oncogene receptor tyrosine kinase; A regulator of rod outer segment fragment phagocytosis. |
| MVK | 12q24.11 | Mevalonate kinase; Involved in the synthesis of isopentenyl diphosphate from (R)-mevalonate. |
| NEK2 | 1q32.3 | NIMA (never in mitosis gene A)-related kinase 2; Involved in regulation of centrosome disjunction. |
| NEUROD1 | 2q31.3 | Neuronal differentiation protein 1; Acts as a transcriptional activator. |
| NR2E3 | 15q23 | Nuclear receptor subfamily 2 group E3; Transcription factor, that is an activator of rod development and repressor of cone development. |
| NRL | 14q11.2 | Neural retina leucine zipper; Transcription factor which regulates expression of rod-specific genes, involved in photoreceptor cell development and function |
| OFD1 | Xp22.2 | Oral-facial-digital syndrome 1 protein; Involved in biogenesis of the cilium and controlling centriole length during cell division. |
| PDE6A | 5q32 | Alpha subunit of cGMP phosphodiesterase; involved in visual transduction cycle. |
| PDE6B | 4p16.3 | Beta subunit of cGMP phosphodiesterase; involved in visual transduction cycle. |
| PDE6G | 17q25.3 | Gamma subunit of cGMP phosphodiesterase; involved in visual transduction cycle. |
| POMGNT1 | 1p34.1 | Protein O-linked acetylglucosaminyltransferase 1 (beta 1,2-); Participates in O-mannosyl glycosylation. |
| PRCD | 17q25.1 | Progressive rod-cone degeneration protein; Unknown function. |
| PRIM1 | 12q13.3 | DNA primase small subunit; Polymerase that synthesizes small RNA primers for Okazaki fragments made during discontinuous DNA replication. |
| RBP3 | 10q11.22 | Retinol-binding protein 3 (IRBP); Shuttles 11-cis and all trans retinoids between the retinol isomerase in RPE and visual pigments in photoreceptor cells. |
| RGR | 10q23.1 | RPE-retinal G protein-coupled receptor; may be involved in regulating recycling of retinal. |
| RHO | 3q22.1 | Rhodopsin; Light-induced isomerization of 11-cis to all-trans retinal leading to G-protein activation and release of all-trans retinal. |
| RLBP1 | 15q26.1 | Retinaldehyde-binding protein 1; Soluble retinoid carrier essential for function of photoreceptors. |
| RP1 | 8q11.23-q12.1 | Oxygen-regulated protein 1; Involved in organization of photoreceptor outer segments. |
| RP1L1 | 8p23.1 | Retinitis pigmentosa 1-like 1 protein; Required for differentiation of photoreceptors and organization of photoreceptor outer segments. |
| RP2 | Xp11.3 | Retinitis pigmentosa 2 (X-linked); Involved in trafficking between Golgi and the ciliary membrane. |
| RPE65 | 1p31.2 | Retinoid isomerohydrolase; Involved in production of 11-cis retinal and visual pigment regeneration. |
| RPGR | Xp11.4 | X-linked retinitis pigmentosa GTPase regulator; Involved in ciliogenesis |
| SAG | 2q37.1 | Rod photoreceptor-arrestin; Binds to photoactivated-phosphorylated rhodopsin, thereby apparently preventing the transducin-mediated activation of phosphodiesterase |
| SLC7A14 | 3q26.2 | Solute carrier family 7 member 14; Unknown function. |
| SLC24A1 | 15q22.31 | Solute carrier family 24 (sodium/potassium/calcium exchanger) member 1; Critical component of visual transduction, controlling the calcium concentration of outer segments. |
| SPATA7 | 14q31.3 | Spermatogenesis associated protein 7; Required for recruitment and localization of RPGRIP1 to the photoreceptor cilium. |
| TRNT1 | 3p26.2 | CCA adding tRNA nucleotidyl transferase 1; Adds and repairs CCA sequences necessary for attachment of amino acids to the 3' terminus of tRNA molecules. |
| TTC8 | 14q31.3 | Tetratricopeptide repeat protein 8; Subunit of the BBSome complex required for proper cilia functions. |
| TULP1 | 6p21.31 | Tubby-like protein 1; Required for normal development of photoreceptor synapses. |
| USH2A | 1q41 | Usherin; Involved in photoreceptor cell maintenance. |
| ZNF408 | 11p11.2 | Zinc finger protein 408; Unknown function. |
| ZNF513 | 2p23.3 | Zinc finger protein 513; Transcriptional regulator involved in retinal development and maintenance. |