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Ocular albinism, type I(OA1)

MedGen UID:
90991
Concept ID:
C0342684
Disease or Syndrome
Synonyms: Nettleship-Falls type ocular albinism; OA1; Ocular albinism type 1; Ocular albinism, type I, Nettleship-Falls type; Ocular Albinism, X-Linked; X-linked recessive ocular albinism
SNOMED CT: OA1 - X-linked ocular albinism (78642008); X-linked ocular albinism (78642008); X-linked recessive ocular albinism (78642008); X-linked ocular albinism, Nettleship type (78642008); Nettleship-Falls type ocular albinism (78642008); Ocular albinism, type I (78642008); X linked ocular albinism (78642008)
Modes of inheritance:
X-linked recessive inheritance
MedGen UID:
375779
Concept ID:
C1845977
Finding
Source: Orphanet
A mode of inheritance that is observed for recessive traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked recessive disorders manifest in males (who have one copy of the X chromosome and are thus hemizygotes), but generally not in female heterozygotes who have one mutant and one normal allele.
 
Gene (location): GPR143 (Xp22.2)
 
Monarch Initiative: MONDO:0021019
OMIM®: 300500
Orphanet: ORPHA54

Definition

Ocular albinism type I (OA1) is the most common form of ocular albinism. Clinical presentation of OA1 in Caucasians is characterized by nystagmus, impaired visual acuity, iris hypopigmentation with translucency, albinotic fundus, macular hypoplasia, and normally pigmented skin and hair. Carrier females usually have punctate iris translucency and a mottled pattern of fundus pigmentation. In contrast to Caucasian patients, black or Japanese patients with OA1 often have brown irides with little or no translucency and varying degrees of fundus hypopigmentation, the so-called 'nonalbinotic fundus' (summary by Xiao and Zhang, 2009). [from OMIM]

Additional description

From MedlinePlus Genetics
Unlike some other forms of albinism, ocular albinism does not significantly affect the color of the skin and hair. People with this condition may have a somewhat lighter complexion than other members of their family, but these differences are usually minor.

The most common form of ocular albinism is known as the Nettleship-Falls type or type 1. Other forms of ocular albinism are much rarer and may be associated with additional signs and symptoms, such as hearing loss.

Ocular albinism is characterized by severely impaired sharpness of vision (visual acuity) and problems with combining vision from both eyes to perceive depth (stereoscopic vision). Although the vision loss is permanent, it does not worsen over time. Other eye abnormalities associated with this condition include rapid, involuntary eye movements (nystagmus); eyes that do not look in the same direction (strabismus); and increased sensitivity to light (photophobia). Many affected individuals also have abnormalities involving the optic nerves, which carry visual information from the eye to the brain.

Ocular albinism is a genetic condition that primarily affects the eyes. This condition reduces the coloring (pigmentation) of the iris, which is the colored part of the eye, and the retina, which is the light-sensitive tissue at the back of the eye. Pigmentation in the eye is essential for normal vision.  https://medlineplus.gov/genetics/condition/ocular-albinism

Clinical features

From HPO
Photophobia
MedGen UID:
43220
Concept ID:
C0085636
Sign or Symptom
Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light.
Giant melanosomes in melanocytes
MedGen UID:
812551
Concept ID:
C3806221
Finding
The presence of large spherical melanosomes (1 to 6 micrometer in diameter) in the cytoplasm of melanocytes.
Nystagmus
MedGen UID:
45166
Concept ID:
C0028738
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
Ocular albinism
MedGen UID:
38147
Concept ID:
C0078917
Congenital Abnormality
An abnormal reduction in the amount of pigmentation (reduced or absent) of the iris and retina.
Reduced visual acuity
MedGen UID:
65889
Concept ID:
C0234632
Finding
Diminished clarity of vision.
Foveal hypoplasia
MedGen UID:
393047
Concept ID:
C2673946
Finding
Underdevelopment of the fovea centralis.
Depigmented fundus
MedGen UID:
870372
Concept ID:
C4024816
Finding
Nystagmus-induced head nodding
MedGen UID:
871300
Concept ID:
C4025788
Disease or Syndrome
Head movements associated with nystagmus, that may represent an attempt to compensate for the involuntary eye movements and to improve vision.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVOcular albinism, type I
Follow this link to review classifications for Ocular albinism, type I in Orphanet.

Professional guidelines

PubMed

Moreno-Artero E, Morice-Picard F, Lasseaux E, Robert MP, Coste V, Michaud V, Leclerc-Mercier S, Bremond-Gignac D, Arveiler B, Hadj-Rabia S
Genes (Basel) 2022 Nov 23;13(12) doi: 10.3390/genes13122198. PMID: 36553465Free PMC Article
Kessel L, Kjer B, Lei U, Duno M, Grønskov K
Ophthalmic Genet 2021 Jun;42(3):230-238. Epub 2021 Feb 22 doi: 10.1080/13816810.2021.1881979. PMID: 33612058
White D, Rabago-Smith M
J Hum Genet 2011 Jan;56(1):5-7. Epub 2010 Oct 14 doi: 10.1038/jhg.2010.126. PMID: 20944644

Recent clinical studies

Etiology

Zhong J, You B, Xu K, Zhang X, Xie Y, Li Y
Ophthalmic Genet 2021 Dec;42(6):717-724. Epub 2021 Aug 4 doi: 10.1080/13816810.2021.1958352. PMID: 34346269

Diagnosis

Zhong J, You B, Xu K, Zhang X, Xie Y, Li Y
Ophthalmic Genet 2021 Dec;42(6):717-724. Epub 2021 Aug 4 doi: 10.1080/13816810.2021.1958352. PMID: 34346269
Han R, Wang X, Wang D, Wang L, Yuan Z, Ying M, Li N
Sci Rep 2015 Jul 10;5:12031. doi: 10.1038/srep12031. PMID: 26160353Free PMC Article
Roma C, Ferrante P, Guardiola O, Ballabio A, Zollo M
Gene 2007 Nov 1;402(1-2):20-7. Epub 2007 Aug 1 doi: 10.1016/j.gene.2007.07.020. PMID: 17822861

Clinical prediction guides

Mao X, Chen M, Yu Y, Liu Q, Yuan S, Fan W
BMC Ophthalmol 2021 Mar 30;21(1):156. doi: 10.1186/s12886-021-01905-7. PMID: 33785018Free PMC Article
Incerti B, Cortese K, Pizzigoni A, Surace EM, Varani S, Coppola M, Jeffery G, Seeliger M, Jaissle G, Bennett DC, Marigo V, Schiaffino MV, Tacchetti C, Ballabio A
Hum Mol Genet 2000 Nov 22;9(19):2781-8. doi: 10.1093/hmg/9.19.2781. PMID: 11092754

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