SNOMEDCT: 722059002; ORPHA: 352745; DO: 0070100;
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
Gene/Locus |
Gene/Locus MIM number |
|---|---|---|---|---|---|---|
| 10q22.2-q22.3 | Albinism, oculocutaneous, type VII | 615179 | Autosomal recessive | 3 | LRMDA | 614537 |
A number sign (#) is used with this entry because of evidence that oculocutaneous albinism type VII (OCA7) is caused by homozygous mutation in the C10ORF11 gene (LRMDA; 614537) on chromosome 10q22.
Oculocutaneous albinism type VII (OCA7) is an autosomal recessive hypopigmentation disorder with predominant eye involvement including nystagmus, iris transillumination, and crossed asymmetry of the cortical visual response (Gronskov et al., 2013).
For a general phenotypic description and a discussion of genetic heterogeneity of oculocutaneous albinism, see OCA1 (203100).
Gronskov et al. (2013) studied individuals with oculocutaneous albinism (OCA) due to mutations in the C10ORF11 gene (see MOLECULAR GENETICS). The authors stated that most of the affected individuals had a light complexion with a tendency to lighter pigmentation than that of their relatives; eye symptoms predominated, with nystagmus and iris transillumination present in all patients. Extremely sparse pigmentation of the peripheral ocular fundus was seen. Visual evoked potentials showed crossed asymmetry of the cortical visual response (misrouting) in all tested individuals. Photophobia was not a major problem. Hair color varied from pale blond to dark brown.
The transmission pattern of OCA7 in the Faroese family reported by Gronskov et al. (2013) was consistent with autosomal recessive inheritance.
In a consanguineous Faroese family with OCA, Gronskov et al. (2013) performed homozygosity mapping and identified a 3.5-Mb homozygous region on chromosome 10q22.2-q22.3 (chr10:77,233,812-80,685,953; GRCh37) that segregated with disease in the family. Analysis of 3 additional unrelated patients, including 2 sisters, revealed homozygosity in an overlapping region.
In a consanguineous Faroese family with OCA mapping to chromosome 10q22.2-q22.3, Gronskov et al. (2013) analyzed the candidate gene C10ORF11 and identified homozygosity for a nonsense mutation (R194X; 614537.0001) that segregated with disease. Screening of an additional 8 unrelated Faroese probands with OCA revealed 5 patients who were also homozygous for the R194X mutation. Analysis of 92 controls from the Faroe Islands detected 3 heterozygous carriers of R194X, corresponding to a carrier frequency of 3.3%. Screening of 48 OCA patients residing in Denmark identified 1 patient of Lithuanian origin, known to be negative for mutation in other OCA-associated genes, who was apparently homozygous for a 1-bp duplication in the C10ORF11 gene (614537.0002).
Based on a consensus of the albinism research community (Montoliu et al., 2013), the form of oculocutaneous albinism caused by mutation in the C10ORF11 gene is here designated OCA7.
Gronskov, K., Dooley, C. M., Ostergaard, E., Kelsh, R. N., Hansen, L., Levesque, M. P., Vilhelmsen, K., Mollgard, K., Stemple, D. L., Rosenberg, T. Mutations in C10orf11, a melanocyte-differentiation gene, cause autosomal-recessive albinism. Am. J. Hum. Genet. 92: 415-421, 2013. [PubMed: 23395477] [Full Text: https://doi.org/10.1016/j.ajhg.2013.01.006]
Montoliu, L., Gronskov, K., Wei, A.-H., Martinez-Garcia, M., Fernandez, A., Arveiler, B., Morice-Picard, F., Riazuddin, S., Suzuki, T., Ahmed, Z. M., Rosenberg, T., Li, W. Increasing the complexity: new genes and new types of albinism. Pigment Cell Melanoma Res. 27: 11-18, 2013. [PubMed: 24066960] [Full Text: https://doi.org/10.1111/pcmr.12167]