Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038379 (strabismus)
 9,317 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Albinism, caused by a deficiency of melanin pigment in the skin, hair, and eye (oculocutaneous albinism [OCA]), or primarily in the eye (ocular albinism [OA]), results from mutations in genes involved in the biosynthesis of melanin pigment. The lack of melanin pigment in the developing eye leads to fovea hypoplasia and abnormal routing of the optic nerves. These changes are responsible for the nystagmus, strabismus, and reduced visual acuity common to all types of albinism. Mutations in six genes have been reported to be responsible for different types of oculocutaneous and ocular albinism, including the tyrosinase gene (TYR) and OCA1 (MIM# 203100), the OCA2 gene and OCA2 (MIM# 203200), the tyrosinase-related protein-1 gene (TYRP1) and OCA3 (MIM# 203290), the HPS gene and Hermansky-Pudlak syndrome (MIM# 203300), the CHS gene (CHS1), and Chediak-Higashi syndrome (MIM# 214500), and the X-linked ocular albinism gene and OA1 (MIM#300500). The function of only two of the gene products is known tyrosinase and tyrosinase-related protein-1 both of which are enzymes in the melanin biosynthetic pathway. Continued mutational analysis coupled with function/structure studies should aid our understanding of the function of the remaining genes and their role in albinism. Mutation and polymorphism data on these genes are available from the International Albinism Center Albinism Database web site (http://www.cbc.umn.edu/tad).
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PMID:Molecular basis of albinism: mutations and polymorphisms of pigmentation genes associated with albinism. 1009 67

Oculocutaneous albinism (OCA) affects approximately 1/20,000 people worldwide. All forms of OCA exhibit generalized hypopigmentation. Reduced pigmentation during eye development results in misrouting of the optic nerves, nystagmus, alternating strabismus, and reduced visual acuity. Loss of pigmentation in the skin leads to an increased risk for skin cancer. Two common forms and one infrequent form of OCA have been described. OCA1 (MIM 203100) is associated with mutations of the TYR gene encoding tyrosinase (the rate-limiting enzyme in the production of melanin pigment) and accounts for approximately 40% of OCA worldwide. OCA2 (MIM 203200), the most common form of OCA, is associated with mutations of the P gene and accounts for approximately 50% of OCA worldwide. OCA3 (MIM 203290), a rare form of OCA and also known as "rufous/red albinism," is associated with mutations in TYRP1 (encoding tyrosinase-related protein 1). Analysis of the TYR and P genes in patients with OCA suggests that other genes may be associated with OCA. We have identified the mouse underwhite gene (uw) and its human orthologue, which underlies a new form of human OCA, termed "OCA4." The encoded protein, MATP (for "membrane-associated transporter protein") is predicted to span the membrane 12 times and likely functions as a transporter.
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PMID:Mutations in the human orthologue of the mouse underwhite gene (uw) underlie a new form of oculocutaneous albinism, OCA4. 1157 7

Oculocutaneous albinism (OCA) is a group of inherited disorders of melanin biosynthesis characterized by a generalized reduction in pigmentation of hair, skin and eyes. The prevalence of all forms of albinism varies considerably worldwide and has been estimated at approximately 1/17,000, suggesting that about 1 in 70 people carry a gene for OCA. The clinical spectrum of OCA ranges, with OCA1A being the most severe type with a complete lack of melanin production throughout life, while the milder forms OCA1B, OCA2, OCA3 and OCA4 show some pigment accumulation over time. Clinical manifestations include various degrees of congenital nystagmus, iris hypopigmentation and translucency, reduced pigmentation of the retinal pigment epithelium, foveal hypoplasia, reduced visual acuity usually (20/60 to 20/400) and refractive errors, color vision impairment and prominent photophobia. Misrouting of the optic nerves is a characteristic finding, resulting in strabismus and reduced stereoscopic vision. The degree of skin and hair hypopigmentation varies with the type of OCA. The incidence of skin cancer may be increased. All four types of OCA are inherited as autosomal recessive disorders. At least four genes are responsible for the different types of the disease (TYR, OCA2, TYRP1 and MATP). Diagnosis is based on clinical findings of hypopigmentation of the skin and hair, in addition to the characteristic ocular symptoms. Due to the clinical overlap between the OCA forms, molecular diagnosis is necessary to establish the gene defect and OCA subtype. Molecular genetic testing of TYR and OCA2 is available on a clinical basis, while, at present, analysis of TYRP1 and MATP is on research basis only. Differential diagnosis includes ocular albinism, Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, Griscelli syndrome, and Waardenburg syndrome type II. Carrier detection and prenatal diagnosis are possible when the disease causing mutations have been identified in the family. Glasses (possibly bifocals) and dark glasses or photocromic lenses may offer sufficient help for reduced visual activity and photophobia. Correction of strabismus and nystagmus is necessary and sunscreens are recommended. Regular skin checks for early detection of skin cancer should be offered. Persons with OCA have normal lifespan, development, intelligence and fertility.
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PMID:Oculocutaneous albinism. 1798 20

Albinism is a heterogeneous genetic disorder of melanin synthesis that results in hypopigmented hair, skin and eyes. It is associated with decreased visual acuity, nystagmus, strabismus and photophobia. Six genes are known to be involved in nonsyndromic oculocutaneous albinism (OCA). In this study, we aimed to find the disease causing mutations in albinism patients using homozygosity mapping. Twenty three unrelated patients with nonsyndromic OCA or autosomal recessive ocular albinism were recruited in this study. All of the patients' parents had consanguineous marriage and all were screened for TYR mutations previously. At first, we performed homozygosity mapping using fluorescently labeled primers to amplify a novel panel of 13 STR markers inside the OCA genes and then the screened loci in each family were studied using PCR and cycle sequencing methods. We found five mutations including three mutations in OCA2, one mutation in SLC45A2 and one mutation in C10ORF11 genes, all of which were novel. In cases where the disease causing mutations are identical by descent due to a common ancestor, these STR markers can enable us to screen for the responsible genes.
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PMID:Homozygosity mapping in albinism patients using a novel panel of 13 STR markers inside the nonsyndromic OCA genes: introducing 5 novel mutations. 2681 37