MCID: ALB010
MIFTS: 32

Albinism, Oculocutaneous, Type Ib

Categories: Genetic diseases, Rare diseases, Eye diseases, Skin diseases, Metabolic diseases

Aliases & Classifications for Albinism, Oculocutaneous, Type Ib

MalaCards integrated aliases for Albinism, Oculocutaneous, Type Ib:

Name: Albinism, Oculocutaneous, Type Ib 53 13 69
Oca1b 53 49 55 71 51
Oculocutaneous Albinism Type 1b 49 55 28
Yellow Albinism 53 49 71
Albinism, Yellow Mutant Type 53 49
Albinism, Oculocutaneous, Type I, Temperature-Sensitive 69
Temperature-Sensitive Oculocutaneous Albinism Type 1 55
Oculocutaneous Albinism Type I Temperature-Sensitive 71
Minimal Pigment Oculocutaneous Albinism 69
Oculocutaneous Albinism, Amish Type 55
Oculocutaneous Albinism, Type Ib 53
Platinum Oculocutaneous Albinism 55
Oculocutaneous Albinism Type Ib 71
Yellow Oculocutaneous Albinism 55
Albinism, Oculocutaneous, 1b 71
Albinism Yellow Mutant Type 71
Yellow Mutant Albinism 49
Ts Oca Type 1 55
Oca1-Ts 55
Oca-Its 71
Oca-Ib 71

Characteristics:

Orphanet epidemiological data:

55
temperature-sensitive oculocutaneous albinism type 1
Inheritance: Autosomal recessive; Prevalence: <1/1000000 (Worldwide); Age of onset: Infancy,Neonatal;
oculocutaneous albinism type 1b
Inheritance: Autosomal recessive; Prevalence: 1-9/100000 (Worldwide); Age of onset: Infancy,Neonatal; Age of death: normal life expectancy;

HPO:

31
albinism, oculocutaneous, type ib:
Inheritance autosomal recessive inheritance


Classifications:



Summaries for Albinism, Oculocutaneous, Type Ib

NIH Rare Diseases : 49 The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.Orpha Number: 79434Disease definitionOculocutaneous albinism type 1B (OCA1B) is a type of OCA1 (see this term) characterized by skin and hair hypopigmentation, nystagmus, reduced iris and retinal pigment and misrouting of the optic nerves.EpidemiologyThe worldwide prevalence of OCA1 is estimated at 1/40,000. OCA1B is considered to account for about half of all overall OCA1 cases among non-Hispanic Caucasian patients.Clinical descriptionNewborns have white or very light yellow hair but with age the hair can darken to blond or light brown. Eyelash hair can be darker than scalp and eyebrow hair. Skin remains creamy white but a minimal amount of tanning is possible along with freckles and pigmented nevi. Nytagmus is sometimes visible at birth but in others not until 3 to 4 months of age. It continues throughout life but becomes less rapid with age and is usually more noticeable in times of stress, anger or tiredness. Iris color is blue at birth and can change to brownish tan or greenish hazel or remain unchanged. Visual acuity ranges from 20/100 to 20/200. With time, skin can become rough, coarse and thickened if sun protection procedures are not followed. Patients have an increased risk of developing basal and squamous cell carcinomas but melanomas are rare.EtiologyOCA1B is caused by a mutation in the TYR gene located on chromosome 11q14.2 encoding tyrosinase. The mutation causes the production of a partially active or hypomorphic tyrosinase enzyme that leads to minimal melanin formation in melanocytes.Diagnostic methodsThe characteristic clinical findings along with confirmatory genetic testing are used to diagnose OCA1B. Ophthalmologic examination reveals visualization of the choroidal blood vessels, reduced retinal pigment and foveal hypoplasia. Alternating strabismus, reduced stereoscopic vision, and an altered visual evoked potential (VEP) are associated with the characteristic misrouting of the optic nerves at the chiasm. Molecular genetic testing is necessary to obtain a definitive diagnosis, as some OCA1B patients have a certain degree of phenotypical variation which may lead to confusion in distinguishing it from other OCAs. This overlap of clinical symptoms emphasizes the importance of genetic analysis in the diagnosis of albinism.Differential diagnosisDifferential diagnoses include the other forms of OCA and X-linked recessive ocular albinism (XLOA) as well as syndromes with albinism as a feature such as Hermansky-Pudlak syndromes 1-9, Chediak-Higashi syndrome, Griscelli syndromes 1-3, and Waardenburg syndrome type II (see these terms).Antenatal diagnosisPrenatal testing is theoretically possible for at risk pregnancies by molecular genetic testing although there are no reports of it having been performed.Genetic counselingThis disorder is inherited autosomal recessively and genetic counseling is available.Management and treatmentAnnual ophthalmologic examination is necessary and corrective lenses or glasses are given to improve visual acuity. Dark glasses may be needed to relieve photophobia. Strabismus surgery can be performed for functional or cosmetic reasons. Protection from sunlight is imperative and patients should wear clothing and sunscreen on exposed skin to prevent burning and reduce the risk of skin cancer. Annual skin examinations should also be performed to identify any pre-cancerous or cancerous lesions.PrognosisOCA1B is not life threatening and remains stable after childhood. The medical and social consequences can however have major impacts on a patient's daily life.Visit the Orphanet disease page for more resources. Last updated: 4/1/2013

MalaCards based summary : Albinism, Oculocutaneous, Type Ib, also known as oca1b, is related to albinism, oculocutaneous, type ia and oculocutaneous albinism, and has symptoms including photophobia, nystagmus and visual impairment. An important gene associated with Albinism, Oculocutaneous, Type Ib is TYR (Tyrosinase). The drug Nitisinone has been mentioned in the context of this disorder. Affiliated tissues include skin, eye and testes.

OMIM : 53 Oculocutaneous albinism type I is an autosomal recessive disorder characterized by absence of pigment in hair, skin, and eyes, and does not vary with race or age. Severe nystagmus, photophobia, and reduced visual acuity are common features. OCA type I is divided into 2 types: type IA, characterized by complete lack of tyrosinase activity due to production of an inactive enzyme, and type IB, characterized by reduced activity of tyrosinase. Although OCA caused by mutations in the TYR gene was classically known as 'tyrosinase-negative' OCA, Tripathi et al. (1992) noted that some patients with 'tyrosinase-positive' OCA may indeed have TYR mutations resulting in residual enzyme activity. These patients can be classified as having OCA1B. (606952)

UniProtKB/Swiss-Prot : 71 Albinism, oculocutaneous, 1B: An autosomal recessive disorder in which the biosynthesis of melanin pigment is reduced in skin, hair, and eyes. It is characterized by partial lack of tyrosinase activity. Patients have white hair at birth that rapidly turns yellow or blond. They manifest the development of minimal-to-moderate amounts of cutaneous and ocular pigment. Some patients may have with white hair in the warmer areas (scalp and axilla) and progressively darker hair in the cooler areas (extremities). This variant phenotype is due to a loss of tyrosinase activity above 35-37 degrees C.

Related Diseases for Albinism, Oculocutaneous, Type Ib

Diseases in the Oculocutaneous Albinism family:

Albinism, Oculocutaneous, Type Vi Albinism, Oculocutaneous, Type Ia
Albinism, Oculocutaneous, Type Ii Albinism, Oculocutaneous, Type Iii
Albinism, Oculocutaneous, Type Iv Albinism, Oculocutaneous, Type Ib
Albinism, Oculocutaneous, Type Vii Albinism, Oculocutaneous, Type V

Diseases related to Albinism, Oculocutaneous, Type Ib via text searches within MalaCards or GeneCards Suite gene sharing:

# Related Disease Score Top Affiliating Genes
1 albinism, oculocutaneous, type ia 10.9
2 oculocutaneous albinism 9.9
3 albinism 9.9

Symptoms & Phenotypes for Albinism, Oculocutaneous, Type Ib

Clinical features from OMIM:

606952

Human phenotypes related to Albinism, Oculocutaneous, Type Ib:

55 31 (show all 18)
# Description HPO Frequency Orphanet Frequency HPO Source Accession
1 photophobia 55 31 frequent (33%) Frequent (79-30%) HP:0000613
2 nystagmus 55 31 frequent (33%) Frequent (79-30%) HP:0000639
3 visual impairment 55 31 frequent (33%) Frequent (79-30%) HP:0000505
4 abnormality of retinal pigmentation 55 31 hallmark (90%) Very frequent (99-80%) HP:0007703
5 strabismus 55 31 hallmark (90%) Very frequent (99-80%) HP:0000486
6 melanocytic nevus 55 31 frequent (33%) Frequent (79-30%) HP:0000995
7 melanoma 55 31 occasional (7.5%) Occasional (29-5%) HP:0002861
8 hypopigmentation of hair 55 31 Very frequent (99-80%) HP:0005599
9 thickened skin 55 31 occasional (7.5%) Occasional (29-5%) HP:0001072
10 iris hypopigmentation 55 31 hallmark (90%) Very frequent (99-80%) HP:0007730
11 squamous cell carcinoma of the skin 55 31 occasional (7.5%) Occasional (29-5%) HP:0006739
12 freckling 55 31 hallmark (90%) Very frequent (99-80%) HP:0001480
13 hypoplasia of the fovea 55 31 frequent (33%) Frequent (79-30%) HP:0007750
14 hypopigmentation of the skin 55 31 Very frequent (99-80%) HP:0001010
15 abnormality of the optic nerve 55 31 frequent (33%) Frequent (79-30%) HP:0000587
16 albinism 55 31 hallmark (90%) Very frequent (99-80%) HP:0001022
17 basal cell carcinoma 55 31 occasional (7.5%) Occasional (29-5%) HP:0002671
18 hypopigmentation of the fundus 31 HP:0007894

Drugs & Therapeutics for Albinism, Oculocutaneous, Type Ib

Drugs for Albinism, Oculocutaneous, Type Ib (from DrugBank, HMDB, Dgidb, PharmGKB, IUPHAR, NovoSeek, BitterDB):


# Name Status Phase Clinical Trials Cas Number PubChem Id
1
Nitisinone Approved, Investigational Phase 1, Phase 2 104206-65-7 115355

Interventional clinical trials:


# Name Status NCT ID Phase Drugs
1 Nitisinone for Type 1B Oculocutaneous Albinism Completed NCT01838655 Phase 1, Phase 2 Nitisinone

Search NIH Clinical Center for Albinism, Oculocutaneous, Type Ib

Genetic Tests for Albinism, Oculocutaneous, Type Ib

Genetic tests related to Albinism, Oculocutaneous, Type Ib:

# Genetic test Affiliating Genes
1 Oculocutaneous Albinism Type 1b 28 TYR

Anatomical Context for Albinism, Oculocutaneous, Type Ib

MalaCards organs/tissues related to Albinism, Oculocutaneous, Type Ib:

38
Skin, Eye, Testes

Publications for Albinism, Oculocutaneous, Type Ib

Articles related to Albinism, Oculocutaneous, Type Ib:

# Title Authors Year
1
Identification of a functionally significant tri-allelic genotype in the Tyrosinase gene (TYR) causing hypomorphic oculocutaneous albinism (OCA1B). ( 28667292 )
2017
2
Ophthalmic features of minimal pigment oculocutaneous albinism. ( 8190479 )
1994

Variations for Albinism, Oculocutaneous, Type Ib

UniProtKB/Swiss-Prot genetic disease variations for Albinism, Oculocutaneous, Type Ib:

71
# Symbol AA change Variation ID SNP ID
1 TYR p.Val275Phe VAR_007669 rs104894314
2 TYR p.Thr325Ala VAR_007675 rs61754379
3 TYR p.Ser380Pro VAR_007681 rs61754391
4 TYR p.His390Asp VAR_007684 rs62645914
5 TYR p.Arg403Ser VAR_007687 rs104894316
6 TYR p.Pro406Leu VAR_007689 rs104894313
7 TYR p.Arg422Gln VAR_007691 rs61754393
8 TYR p.Pro152Ser VAR_007925 rs145513733
9 TYR p.Glu294Lys VAR_007928 rs757754120
10 TYR p.Arg402Gly VAR_007937

ClinVar genetic disease variations for Albinism, Oculocutaneous, Type Ib:

6 (show all 12)
# Gene Variation Type Significance SNP ID Assembly Location
1 TYR NM_000372.4(TYR): c.1037-7T> A single nucleotide variant Pathogenic/Likely pathogenic rs61754381 GRCh37 Chromosome 11, 88960984: 88960984
2 TYR NM_000372.4(TYR): c.551C> G (p.Ser184Ter) single nucleotide variant Likely pathogenic rs367543066 GRCh38 Chromosome 11, 89178504: 89178504
3 TYR NM_000372.4(TYR): c.739T> C (p.Cys247Arg) single nucleotide variant Likely pathogenic rs367543068 GRCh38 Chromosome 11, 89178692: 89178692
4 TYR NM_000372.4(TYR): c.242C> T (p.Pro81Leu) single nucleotide variant Pathogenic/Likely pathogenic rs28940876 GRCh37 Chromosome 11, 88911363: 88911363
5 TYR NM_000372.4(TYR): c.823G> T (p.Val275Phe) single nucleotide variant Pathogenic rs104894314 GRCh37 Chromosome 11, 88924373: 88924373
6 TYR NM_000372.4(TYR): c.1118C> A (p.Thr373Lys) single nucleotide variant Pathogenic rs61754388 GRCh37 Chromosome 11, 88961072: 88961072
7 TYR NM_000372.4(TYR): c.1147G> A (p.Asp383Asn) single nucleotide variant Pathogenic rs121908011 GRCh37 Chromosome 11, 88961101: 88961101
8 TYR NM_000372.4(TYR): c.1217C> T (p.Pro406Leu) single nucleotide variant Pathogenic/Likely pathogenic rs104894313 GRCh37 Chromosome 11, 89017973: 89017973
9 TYR NM_000372.4(TYR): c.1265G> A (p.Arg422Gln) single nucleotide variant Pathogenic rs61754393 GRCh37 Chromosome 11, 89018021: 89018021
10 TYR NM_000372.4(TYR): c.140G> A (p.Gly47Asp) single nucleotide variant Pathogenic rs61753180 GRCh37 Chromosome 11, 88911261: 88911261
11 TYR NM_000372.4(TYR): c.1467dupT (p.Ala490Cysfs) duplication Pathogenic rs61754399 GRCh37 Chromosome 11, 89028411: 89028411
12 TYR NM_000372.4(TYR): c.1A> G (p.Met1Val) single nucleotide variant Pathogenic rs28940881 GRCh37 Chromosome 11, 88911122: 88911122

Expression for Albinism, Oculocutaneous, Type Ib

Search GEO for disease gene expression data for Albinism, Oculocutaneous, Type Ib.

Pathways for Albinism, Oculocutaneous, Type Ib

GO Terms for Albinism, Oculocutaneous, Type Ib

Sources for Albinism, Oculocutaneous, Type Ib

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65 SNOMED-CT via HPO
66 SNOMED-CT via Orphanet
67 TGDB
68 Tocris
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70 UMLS via Orphanet
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