Alternative titles; symbols
HGNC Approved Gene Symbol: GPR143
SNOMEDCT: 78642008; ICD10CM: E70.310;
Cytogenetic location: Xp22.2 Genomic coordinates (GRCh38) : X:9,725,346-9,778,602 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| Xp22.2 | Nystagmus 6, congenital, X-linked | 300814 | X-linked recessive | 3 |
| Ocular albinism, type I, Nettleship-Falls type | 300500 | X-linked | 3 |
GPR143 is a G protein-coupled receptor (GPCR) that is exclusively expressed by melanocytes and retinal pigment epithelium (RPE). Unlike other GPCRs, GPR143 is not localized to the cell surface, but is exclusively found on the membranes of intracellular organelles, namely late endosomes/lysosomes and melanosomes (summary by Palmisano et al. (2008)).
By hybridization of the ocular albinism type I (OA1; 300500) critical region in 4 patients to a human retina cDNA library, followed by RACE-PCR analysis, Bassi et al. (1995) cloned GPR143. RT-PCR analysis detected a 1.6-kb transcript that was expressed at high levels in RNA samples from retina, including RPE, and from melanoma, with weak expression in brain and adrenal gland. The deduced 424-amino acid GPR143 protein has at least 6 putative transmembrane domains.
Newton et al. (1996) cloned and characterized mouse Gpr143, which they referred to as Moa1. Two Moa1 variants were isolated from a melanoma cDNA library and predicted proteins of 405 and 249 amino acids with 6 and 2 transmembrane-spanning regions, respectively. In adult tissues, both Moa1 isoforms were detected in the eye by Northern hybridization. In neonatal tissues, Moa1 RNA was detected in both skin and eye by Northern hybridization and was not affected by the absence of pigment in mice carrying the 'albino' mutation or by the type of pigment synthesized, i.e., eumelanin or pheomelanin, in mice carrying the 'black-and-tan' mutation. Expression of Moa1 RNA was not detected in embryonic tissues by Northern analysis or by in situ hybridization despite the active synthesis of ocular pigment by embryonic stage E16.5.
By immunogold electron microscopy of human melanocytic cell line MNT-1, Giordano et al. (2009) showed that GPR143 was widely distributed throughout the endo-melanosomal system but that most of the endogenous protein was localized in unpigmented stage II melanosomes.
Schiaffino et al. (1995) determined that the GPR143 gene contains 9 exons and spans 40 kb.
Vetrini et al. (2004) identified several putative transcription factor-binding sites in the 5-prime proximal region of the OA1 promoter, including sites for SP1 (189906), GBX2 (601135), HES1 (139605), and MITF (156845). There is no TATA box. The mouse Oa1 promoter region shows a nearly identical organization. Using several in vitro and in vivo approaches, Vetrini et al. (2004) confirmed that the MITF site, an E-box at position -28 from the transcription start site, was bound by the MITF-M isoform and was functional in pigmented mouse and human cells. MITF-M could drive expression of OA1 in melanocytes and retinal pigment epithelium.
Bassi et al. (1995) mapped the GPR143 gene to chromosome Xp22.3-p22.2, approximately 20 kb on the telomeric side of the APXL gene (SHROOM2; 300103). APXL spans 80 of the 110 kb of the OA1 critical region.
Comparative mapping of the X chromosome in eutherian mammals has revealed distinct regions of conservation as well as evolutionary rearrangements between human and mouse. Dinulos et al. (1996) mapped the murine homologs of OA1 and APXL. They found that the 2 genes map to bands F2-F3 in both M. spretus and the laboratory strains C57BL/6J, defining a new rearrangement between human and mouse X chromosomes.
Interspecific backcross mapping by Newton et al. (1996) yielded a map order and distances (in cM) of cen-Moa1-3.1 +/- 1.8-Piga (311770)-2.1 +/- 1.5-Amel (AMELX; 300391), indicating that Moa1 is located much farther away from the pseudoautosomal region than its human homolog.
GPCRs participate in the most common signal transduction system at the plasma membrane. The wide distribution of heterotrimeric G proteins in the internal membranes suggests that a similar signaling mechanism might also be used at intracellular locations. Schiaffino et al. (1999) provided structural evidence that the protein product of the OA1 gene, a pigment cell-specific integral membrane glycoprotein, represents a novel member of the GPCR superfamily and demonstrated that it binds heterotrimeric G proteins. Moreover, they showed that OA1 is not found at the plasma membrane, being instead targeted to specialized intracellular organelles, the melanosomes. The data suggested that OA1 represents the first example of an exclusively intracellular GPCR and supported the hypothesis that GPCR-mediated signal transduction systems also operate at the internal membranes in mammalian cells.
Giordano et al. (2009) used siRNA inactivation of GPR143 and combined morphologic and biochemical methods to investigate melanosome ultrastructure, melanosomal protein localization and expression in human pigmented melanocytic cells. GPR143 loss of function led to decreased pigmentation and caused formation of enlarged aberrant premelanosomes harboring disorganized fibrillar structures and displaying proteins of mature melanosomes and lysosomes at their membrane. GPR143 interacted biochemically with the premelanosomal protein MART1 (MLANA; 605513). Inactivation of MART1 by siRNA led to decreased stability of GPR143 and was accompanied by similar defects in premelanosome biogenesis and composition. Giordano et al. (2009) concluded that melanosome composition and identity are regulated at early stages by GPR143 and that MART1 likely acts as an escort protein for GPR143.
Ocular Albinism Type I
Bassi et al. (1995) identified 5 patients with OA1 (300500) who were carrying mutations within the GPR143 gene. Five intragenic deletions and a 2-bp insertion resulting in a premature stop codon (300808.0001) were identified by DNA analysis of patients with OA1. Some of these deletions were not overlapping, making it highly unlikely that the mutation involved in OA1 is located in an intron of the gene. Fine molecular characterization of the gene in 1 patient demonstrated that the deletion removed part of a coding exon. The APXL gene was completely deleted in 1 patient with isolated OA1. However, an extensive search for point mutations was performed in the 4,848-bp coding region of APXL from 57 patients and no functionally relevant mutation was identified.
Schiaffino et al. (1995) screened the entire OA1 coding region and 5-prime and 3-prime sequences for mutations and detected mutations in only one-third (21 of 60) of their patients with OA, including 2 frameshifts (e.g., 300808.0002) and a splice site mutation leading to truncated OA1 proteins, a deletion of a threonine codon at position 290, and 4 missense mutations (e.g., 300808.0008), 2 of which involved amino acids located within putative transmembrane domains.
Schnur et al. (1998) reported results of deletion and mutation screening of the full-length OA1 gene in 29 unrelated North American and Australian OA probands, including 5 with additional, nonocular phenotypic abnormalities (Schnur et al., 1994). They detected 13 intragenic gene deletions, including 3 of exon 1, 2 of exon 2, 2 of exon 4, and 6 others, which span exons 2 to 8. They also identified 8 novel missense mutations that clustered within exons 1, 2, 3, and 6 in conserved and/or putative transmembrane domains of the protein. There was also a splice acceptor site mutation, a nonsense mutation, a single base deletion, and a previously reported 17-bp exon 1 deletion. All patients with nonocular phenotypic abnormalities had detectable mutations. All told, 26 (approximately 90%) of 29 probands had detectable alterations in the OA1 gene, thus confirming that OA1 is the major locus for X-linked OA.
In Denmark, Rosenberg and Schwartz (1998) performed a retrospective survey of 112 patients with ocular albinism identified in a national register, including 60 male patients with proven or presumed X-linked ocular albinism. Based on the birth year cohorts 1960 to 1989, a point prevalence for OA1 at birth of 1 in 60,000 live born was calculated. They identified 14 OA1 families in the Danish population and obtained DNA from affected persons in 9 families. Mutation analysis demonstrated 7 presumed pathogenic mutations in the 9 families: 5 single nucleotide substitutions predicting a change of conserved amino acids, including G35D (300808.0008) and W133R (300808.0006), when compared with the mouse OA1 homolog, 1 deletion leading to the skipping of exon 2, and 1 example of a single nucleotide substitution expected to affect the 5-prime splice site of intron 2 (300808.0007). Subsequent genealogic investigations in the 3 families harboring the same mutation, W133R, disclosed that 2 of the 3 belonged to the same family. Clinical examination failed to identify any phenotype-genotype pattern except for the finding of a milder phenotype lacking iris translucency in the patient with the 5-prime splice site mutation of intron 2.
D'Addio et al. (2000) characterized 19 independent missense mutations with respect to processing and subcellular distribution on expression in COS-7 cells. Eleven of the 19 OA1 mutants (approximately 60%) were retained in the endoplasmic reticulum, showing defective intracellular transport and glycosylation, consistent with protein misfolding. The remaining 8 OA1 mutants (approximately 40%) displayed sorting and processing behaviors indistinguishable from those of the wildtype protein. Most of the latter mutations clustered within the second and third cytosolic loops, 2 regions that in canonical GPCRs are known to be critical for their downstream signaling, including G protein coupling and effector activation.
Oetting (2002) found that a total of 25 missense, 2 nonsense, 9 frameshift, and 5 splicing mutations in the OA1 gene had been reported in association with type I ocular albinism. There were also reports of several deletions of some or all exons of the OA1 gene with deletions of exon 2 resulting from unequal crossing-over, due to flanking Alu repeats. Oetting (2002) referred to an albinism database website.
In a Chinese patient with ocular albinism, Xiao and Zhang (2009) identified an intragenic deletion in the GPR143 gene (300808.0013).
X-linked Congenital Nystagmus 6
In a large 6-generation Chinese family with congenital nystagmus as the main feature (NYS6; 300814), Liu et al. (2007) analyzed 21 candidate genes and identified a missense mutation in the GPR143 gene (S89F; 300808.0009) in affected males and carrier females.
Zhou et al. (2008) and Peng et al. (2009) identified mutations in the GPR143 gene (300808.0011 and 300808.0012, respectively) in 2 unrelated Chinese families with X-linked recessive congenital nystagmus without features of ocular albinism. Female carriers were unaffected.
Incerti et al. (2000) generated and characterized Oa1-deficient mice by gene targeting. Knockout males were viable, fertile, and phenotypically indistinguishable from wildtype littermates. Ophthalmologic examination showed hypopigmentation of the ocular fundus in mutant animals compared with wildtype. Analysis of the retinofugal pathway revealed a reduction in the size of the uncrossed pathway, demonstrating a misrouting of the optic fibers at the chiasm, as observed in OA1 patients. Microscopic examination of the RPE showed the presence of giant melanosomes comparable with those described in OA1 patients. Ultrastructural analysis of the RPE cells suggested that the giant melanosomes may form by abnormal growth of single melanosomes rather than by the fusion of several organelles.
Palmisano et al. (2008) found reduced melanosome number and abnormal melanosome distribution toward the apical pole of Oa1 -/- RPE at embryonic stages that preceded the formation of macromelanosomes. In cultured -/- skin melanocytes, melanosomes were depleted from the perinuclear area and accumulated toward the cell periphery. In Oa1 -/- melanocytes, melanosomes interacted normally with the microtubule cytoskeleton and recruited factors required for actin-mediated melanosome capture; however, Oa1 -/- melanosomes appeared unable to release from the peripheral actin filaments. Palmisano et al. (2008) concluded that OA1 plays a regulatory role in distributing melanosomes between microtubule- and actin-based cytoskeletal elements.
In 4 apparently unrelated families with OA1 (300500), Bassi et al. (1995) found an insertional mutation of a CG dinucleotide at position 992 of the cDNA. Such CG dinucleotide insertions have been attributed to the symmetric element GCCG immediately following the insertion site (Cooper and Krawczak, 1991). The mutation completely cosegregated with the disease allele in the 4 families and produced a frameshift in the predicted protein product with a subsequent premature stop codon 20 amino acids downstream. The identification of this same mutational event in 4 families from the same region in the Netherlands suggested founder effect. Since all 4 families had multiple affected members in at least 4 generations, it was not possible to trace the origin of the mutation. It is likely that they share a common ancestor. Another such large pedigree on which clinical records date back to the 19th century was identified in Newfoundland by the Canadian National Institute for the Blind (Johnson et al., 1971).
In probands of a British family with OA1 (300500), Schiaffino et al. (1995) identified a 17-bp deletion within exon 1 of the GPR143 gene, producing a frameshift leading to a premature stop codon. Schnur et al. (1998) identified the same mutation in probands of an Australian-British family with OA1.
In a patient with OA1 (300500), Schnur et al. (1998) identified a missense mutation that converted codon 133 from TGG (trp) to CGG (arg) (W133R). The patients also showed developmental delay and renal and immune dysfunction. In another family, the same W133R mutation was found. That family was of interest because a manifesting female had a 45,XO karyotype (Turner syndrome).
In a patient with ocular albinism (OA1; 300500) and giant pigment granules in melanocytes, Schnur et al. (1998) demonstrated a mutation changing codon 152 from AGC (ser) to AAC (asn) (S152N) in the OA1 gene. The patient also had Becker-type muscular dystrophy (300376), which Schnur et al. (1998) concluded was probably coincidental.
In a patient with OA1 (300500) characterized by the presence of giant pigment granules in melanocytes, Schnur et al. (1998) identified a thr232-to-lys (T232K) missense mutation resulting from a change of ACG to AAG in the OA1 gene. The mother had a normal fundus examination; the mother and the affected grandfather had 'vitiligo.'
In 3 presumably unrelated Danish families with OA1 (300500), Rosenberg and Schwartz (1998) found a T-to-A transversion at nucleotide 457 of the OA1 gene that resulted in a trp133-to-arg (W133R) missense mutation in the gene product. Subsequently, 2 of the families were found to be related.
In a patient with X-linked ocular albinism (OA1; 300500), Rosenberg and Schwartz (1998) found deletion of exon 2 and part of the flanking introns resulting from a G-to-A transition at nucleotide 420 of the GPR143 gene. The mutation changed the last nucleotide of exon 2, which per se did not cause any amino acid change; however, the mutation changed the consensus sequence of the donor splice site from GCGgt to GCAgt. The most frequent 3-prime exon sequence of the donor splice site is GAG (Krawczak et al., 1992). The change of the 3-prime sequence of exon 2 to GCA would be expected to weaken or destroy the splicing signal. Such mutations have been found in several genes, e.g., PROC (612283) (Lind et al., 1993), and have been shown to result in exon skipping. The patient with the splice site mutation showed a milder phenotype than did other patients with missense mutations; there was no iris translucency.
In a study of 9 families with X-linked ocular albinism (OA1; 300500), Rosenberg and Schwartz (1998) identified 7 pathogenic mutations. Only 1 of these, gly35 to asp (G35D), had previously been identified (Schiaffino et al., 1995).
In a large 6-generation Chinese family in which 8 males had congenital nystagmus (NYS6; 300814), Liu et al. (2007) identified a 266C-T transition in exon 2 of the GPR143 gene, resulting in a ser89-to-phe (S89F) substitution at a highly conserved residue. The mutation was found in 5 affected males and 4 carrier females and was not found in 4 unaffected family members or 200 controls. The pedigree pattern was consistent with X-linked recessive inheritance.
In affected members of a 3-generation family with variable features of ocular albinism (300500), Preising et al. (2001) identified a 14-bp deletion beginning at nucleotide 816 and affecting the splice donor signal of intron 6 of the GPR143 gene. The male proband was diagnosed with OA1 at age 3 months with typical clinical features, including congenital nystagmus, iris translucency, macular hypoplasia, fundus hypopigmentation, and normal pigmentation of skin and hair. Examination at age 4 years showed increased pigmentation of the iris and fundus and improved visual acuity. A 51-year-old maternal uncle also had congenital nystagmus, clear macular hypoplasia and stromal focal hypopigmentation of the iris, but no iris translucency or fundus hypopigmentation. Macromelanosomes were present on skin biopsy. A 79-year-old maternal relative had congenital nystagmus and high myopia with macular change, but no iris translucency. Two carrier females had mosaic pattern of hypopigmented retinal epithelium, consistent with a carrier status of ocular albinism. RT-PCR studies showed that the 14-bp deletion resulted in a frameshift and premature termination of the protein at residue 259. The resulting gene product lacks the last transmembrane domain from the extracellular loop 3 to the C terminus. Preising et al. (2001) suggested that this mutation results in a hypomorphic allele that causes impaired membrane fusion of melanosomes and the plasma membrane. They proposed a model of OA1 in this family that allowed increase of pigmentation with age. Thus, postnatal normalization of the extracellular dopamine levels due to delayed distribution and membrane budding or fusion of melanosomes in melanocytes could result in increasing pigmentation and a seemingly variable phenotype.
In affected males in a 4-generation Chinese family with congenital nystagmus (300814), Zhou et al. (2008) identified a 37-bp deletion in exon 1 of the GPR143 gene, predicted to result in a frameshift and premature termination. The mutant transcript is likely to be degraded by nonsense-mediated mRNA decay and loss of function. All male mutation carriers had X-linked congenital nystagmus without evidence of ocular albinism. Obligate mutation carriers did not have nystagmus, consistent with X-linked recessive inheritance.
In affected members of a Chinese family with X-linked congenital nystagmus (300814), Peng et al. (2009) identified a 19-bp duplication (291_309) in exon 1 of the GPR143 gene, resulting in a frameshift, premature termination, and nonsense-mediated mRNA decay. All patients were male, and had binocular spontaneous horizontal oscillations without head nodding. They all had reduced vision, amblyopia, and mild compound hypermetropic astigmatism. None of the patients had classic features of ocular albinism. Female carriers were unaffected, consistent with X-linked recessive inheritance.
In a Chinese patient with ocular albinism (OA1; 300500), Xiao and Zhang (2009) identified a deletion of exons 1 and 2 of the GPR143 gene. The patient and his carrier mother both demonstrated an unusual phenotype of iris hyperpigmentation without translucency, with apparent mosaic pigmentation of the fundus.
Bassi, M. T., Schiaffino, M. V., Renieri, A., De Nigris, F., Galli, L., Bruttini, M., Gebbia, M., Bergen, A. A. B., Lewis, R. A., Ballabio, A. Cloning of the gene for ocular albinism type 1 from the distal short arm of the X chromosome. Nature Genet. 10: 13-19, 1995. [PubMed: 7647783] [Full Text: https://doi.org/10.1038/ng0595-13]
Cooper, D. N., Krawczak, M. Mechanisms of insertional mutagenesis in human genes causing genetic disease. Hum. Genet. 87: 409-415, 1991. [PubMed: 1652548] [Full Text: https://doi.org/10.1007/BF00197158]
d'Addio, M., Pizzigoni, A., Bassi, M. T., Baschirotto, C., Valetti, C., Incerti, B., Clementi, M., De Luca, M., Ballabio, A., Schiaffino, M. V. Defective intracellular transport and processing of OA1 is a major cause of ocular albinism type 1. Hum. Molec. Genet. 9: 3011-3018, 2000. [PubMed: 11115845] [Full Text: https://doi.org/10.1093/hmg/9.20.3011]
Dinulos, M. B., Bassi, M. T., Rugarli, E. I., Chapman, V., Ballabio, A., Disteche, C. M. A new region of conservation is defined between human and mouse X chromosomes. Genomics 35: 244-247, 1996. [PubMed: 8661129] [Full Text: https://doi.org/10.1006/geno.1996.0347]
Giordano, F., Bonetti, C., Surace, E. M., Marigo, V., Raposo, G. The ocular albinism type 1 (OA1) G-protein-coupled receptor functions with MART-1 at early stages of melanogenesis to control melanosome identity and composition. Hum. Molec. Genet. 18: 4530-4545, 2009. [PubMed: 19717472] [Full Text: https://doi.org/10.1093/hmg/ddp415]
Incerti, B., Cortese, K., Pizzigoni, A., Surace, E. M., Varani, S., Coppola, M., Jeffery, G., Seeliger, M., Jaissle, G., Bennett, D. C., Marigo, V., Schiaffino, M. V., Tacchetti, C., Ballabio, A. Oa1 knock-out: new insights on the pathogenesis of ocular albinism type 1. Hum. Molec. Genet. 9: 2781-2788, 2000. [PubMed: 11092754] [Full Text: https://doi.org/10.1093/hmg/9.19.2781]
Johnson, G. J., Gillan, J. G., Pearce, W. G. Ocular albinism in Newfoundland. Canad. J. Ophthal. 6: 237-248, 1971. [PubMed: 5125647]
Krawczak, M., Reiss, J., Cooper, D. N. The mutational spectrum of single base-pair substitutions in mRNA splice junctions of human genes: causes and consequences. Hum. Genet. 90: 41-54, 1992. [PubMed: 1427786] [Full Text: https://doi.org/10.1007/BF00210743]
Lind, B., van Solinge, W. W., Schwartz, M., Thorsen, S. Splice site mutation in the human protein C gene associated with venous thrombosis: demonstration of exon skipping by ectopic transcript analysis. Blood 82: 2423-2432, 1993. [PubMed: 8400292]
Liu, J. Y., Ren, X., Yang, X., Guo, T., Yao, Q., Li, L., Dai, X., Zhang, M., Wang, L., Liu, M., Wang, Q. K. Identification of a novel GPR143 mutation in a large Chinese family with congenital nystagmus as the most prominent and consistent manifestation. J. Hum. Genet. 52: 565-570, 2007. [PubMed: 17516023] [Full Text: https://doi.org/10.1007/s10038-007-0152-3]
Newton, J. M., Orlow, S. J., Barsh, G. S. Isolation and characterization of a mouse homolog of the X-linked ocular albinism (OA1) gene. Genomics 37: 219-225, 1996. [PubMed: 8921399] [Full Text: https://doi.org/10.1006/geno.1996.0545]
Oetting, W. S. New insights into ocular albinism type 1 (OA1): mutations and polymorphisms of the OA1 gene. Hum. Mutat. 19: 85-92, 2002. [PubMed: 11793467] [Full Text: https://doi.org/10.1002/humu.10034]
Palmisano, I., Bagnato, P., Palmigiano, A., Innamorati, G., Rotondo, G., Altimare, D., Venturi, C., Sviderskaya, E. V., Piccirillo, R., Coppola, M., Marigo, V., Incerti, B., Ballabio, A., Surace, E. M., Tacchetti, C., Bennett, D. C., Schiaffino, M. V. The ocular albinism type 1 protein, an intracellular G protein-coupled receptor, regulates melanosome transport in pigment cells. Hum. Molec. Genet. 17: 3487-3501, 2008. Note: Erratum: Hum. Molec. Genet. 26: 3028-3029, 2017. [PubMed: 18697795] [Full Text: https://doi.org/10.1093/hmg/ddn241]
Peng, Y., Meng, Y., Wang, Z., Qin, M., Li, X., Dian, Y., Huang, S. A novel GPR143 duplication mutation in a Chinese family with X-linked congenital nystagmus. Molec. Vis. 15: 810-814, 2009. [PubMed: 19390656]
Preising, M., Op de Laak, J.-P., Lorenz, B. Deletion in the OA1 gene in a family with congenital X linked nystagmus. Brit. J. Ophthal. 85: 1098-1103, 2001. [PubMed: 11520764] [Full Text: https://doi.org/10.1136/bjo.85.9.1098]
Rosenberg, T., Schwartz, M. X-linked ocular albinism: prevalence and mutations--a national study. Europ. J. Hum. Genet. 6: 570-577, 1998. [PubMed: 9887374] [Full Text: https://doi.org/10.1038/sj.ejhg.5200226]
Schiaffino, M. V., Bassi, M. T., Galli, L., Renieri, A., Bruttini, M., De Nigris, F., Bergen, A. A. B., Charles, S. J., Yates, J. R. W., Meindl, A., Lewis, R. A., King, R. A., Ballabio, A. Analysis of the OA1 gene reveals mutations in only one-third of patients with X-linked ocular albinism. Hum. Molec. Genet. 4: 2319-2325, 1995. [PubMed: 8634705] [Full Text: https://doi.org/10.1093/hmg/4.12.2319]
Schiaffino, M. V., d'Addio, M., Alloni, A., Baschirotto, C., Valetti, C., Cortese, K., Puri, C., Bassi, M. T., Colla, C., De Luca, M., Tacchetti, C., Ballabio, A. Ocular albinism: evidence for a defect in an intracellular signal transduction system. Nature Genet. 23: 108-112, 1999. [PubMed: 10471510] [Full Text: https://doi.org/10.1038/12715]
Schnur, R. E., Gao, M., Wick, P. A., Keller, M., Benke, P. J., Edwards, M. J., Grix, A. W., Hockey, A., Jung, J. H., Kidd, K. K., Kistenmacher, M., Levin, A. V., and 11 others. OA1 mutations and deletions in X-linked ocular albinism. Am. J. Hum. Genet. 62: 800-809, 1998. [PubMed: 9529334] [Full Text: https://doi.org/10.1086/301776]
Schnur, R. E., Wick, P. A., Bailey, C., Rebbeck, T., Weleber, R. G., Wagstaff, J., Grix, A. W., Pagon, R. A., Hockey, A., Edwards, M. J. Phenotypic variability in X-linked ocular albinism: relationship to linkage genotypes. Am. J. Hum. Genet. 55: 484-496, 1994. [PubMed: 7915878]
Vetrini, F., Auricchio, A., Du, J., Angeletti, B., Fisher, D. E., Ballabio, A., Marigo, V. The microphthalmia transcription factor (Mitf) controls expression of the ocular albinism type 1 gene: link between melanin synthesis and melanosome biogenesis. Molec. Cell. Biol. 24: 6550-6559, 2004. [PubMed: 15254223] [Full Text: https://doi.org/10.1128/MCB.24.15.6550-6559.2004]
Xiao, X., Zhang, Q. Iris hyperpigmentation in a Chinese family with ocular albinism and the GPR143 mutation. Am. J. Med. Genet. 149A: 1786-1788, 2009. [PubMed: 19610097] [Full Text: https://doi.org/10.1002/ajmg.a.32818]
Zhou, P., Wang, Z., Zhang, J., Hu, L., Kong, X. Identification of a novel GPR143 deletion in a Chinese family with X-linked congenital nystagmus. Molec. Vis. 14: 1015-1019, 2008. [PubMed: 18523664]