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Sequence analysis of tyrosinase gene in ocular and oculocutaneous albinism patients: introducing three novel mutations.

Khordadpoor-Deilamani F, Akbari MT, Karimipoor M, Javadi G - Mol. Vis. (2015)

Bottom Line: Albinism is a heterogeneous genetic disorder of melanin synthesis that results in hypopigmented eyes (in patients with ocular albinism) or hair, skin, and eyes (in individuals with oculocutaneous albinism).It is associated with decreased visual acuity, nystagmus, strabismus, and photophobia.We found 10 mutations, 3 of which were novel.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.

ABSTRACT

Purpose: Albinism is a heterogeneous genetic disorder of melanin synthesis that results in hypopigmented eyes (in patients with ocular albinism) or hair, skin, and eyes (in individuals with oculocutaneous albinism). It is associated with decreased visual acuity, nystagmus, strabismus, and photophobia. The tyrosinase gene is known to be involved in both oculocutaneous albinism and autosomal recessive ocular albinism. In this study, we aimed to screen the mutations in the TYR gene in the nonsyndromic OCA and autosomal recessive ocular albinism patients from Iran.

Methods: The tyrosinase gene was examined in 23 unrelated patients with autosomal recessive ocular albinism or nonsyndromic OCA using DNA sequencing and bioinformatics analysis.

Results: TYR gene mutations were identified in 14 (app. 60%) albinism patients.

Conclusions: We found 10 mutations, 3 of which were novel. No mutation was found in our ocular albinism patients, but one of them was heterozygous for the p.R402Q polymorphism.

No MeSH data available.


Related in: MedlinePlus

The pedigree of patient 4. The nonpathogenic nature of p.R402Q and p.S192Y can be inferred from the above pedigree in which the patient’s parents do not show any albinism features.
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f1: The pedigree of patient 4. The nonpathogenic nature of p.R402Q and p.S192Y can be inferred from the above pedigree in which the patient’s parents do not show any albinism features.

Mentions: The contribution of the p.R402Q variant to the albinism phenotype has been heavily disputed in the literature [7,16]. According to our study, it doesn’t seem to be pathogenic. In Figure 1, Figure 2, and Figure 3, the pedigrees of our three OCA patients (patients 4, 9, and 15) are in support of this phenomenon. Nonpathogenicity of p.S192Y can also be inferred from these pedigrees. Since the parents of patient 4 are both homozygous for p.R402Q and p.S192Y, respectively, and do not show the albinism phenotype, none of these variants could be considered pathogenic in the homozygous state (Figure 1). Also, p.S192Y is not pathogenic in heterozygous form in combination with other mutations such as p.R239W or p.M332I in the parents of patient 9 (Figure 2). Moreover, according to the pedigree of patient 15, both p.S192Y and p.R402Q, together with p.G47S, are not pathogenic (Figure 3).


Sequence analysis of tyrosinase gene in ocular and oculocutaneous albinism patients: introducing three novel mutations.

Khordadpoor-Deilamani F, Akbari MT, Karimipoor M, Javadi G - Mol. Vis. (2015)

The pedigree of patient 4. The nonpathogenic nature of p.R402Q and p.S192Y can be inferred from the above pedigree in which the patient’s parents do not show any albinism features.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499471&req=5

f1: The pedigree of patient 4. The nonpathogenic nature of p.R402Q and p.S192Y can be inferred from the above pedigree in which the patient’s parents do not show any albinism features.
Mentions: The contribution of the p.R402Q variant to the albinism phenotype has been heavily disputed in the literature [7,16]. According to our study, it doesn’t seem to be pathogenic. In Figure 1, Figure 2, and Figure 3, the pedigrees of our three OCA patients (patients 4, 9, and 15) are in support of this phenomenon. Nonpathogenicity of p.S192Y can also be inferred from these pedigrees. Since the parents of patient 4 are both homozygous for p.R402Q and p.S192Y, respectively, and do not show the albinism phenotype, none of these variants could be considered pathogenic in the homozygous state (Figure 1). Also, p.S192Y is not pathogenic in heterozygous form in combination with other mutations such as p.R239W or p.M332I in the parents of patient 9 (Figure 2). Moreover, according to the pedigree of patient 15, both p.S192Y and p.R402Q, together with p.G47S, are not pathogenic (Figure 3).

Bottom Line: Albinism is a heterogeneous genetic disorder of melanin synthesis that results in hypopigmented eyes (in patients with ocular albinism) or hair, skin, and eyes (in individuals with oculocutaneous albinism).It is associated with decreased visual acuity, nystagmus, strabismus, and photophobia.We found 10 mutations, 3 of which were novel.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.

ABSTRACT

Purpose: Albinism is a heterogeneous genetic disorder of melanin synthesis that results in hypopigmented eyes (in patients with ocular albinism) or hair, skin, and eyes (in individuals with oculocutaneous albinism). It is associated with decreased visual acuity, nystagmus, strabismus, and photophobia. The tyrosinase gene is known to be involved in both oculocutaneous albinism and autosomal recessive ocular albinism. In this study, we aimed to screen the mutations in the TYR gene in the nonsyndromic OCA and autosomal recessive ocular albinism patients from Iran.

Methods: The tyrosinase gene was examined in 23 unrelated patients with autosomal recessive ocular albinism or nonsyndromic OCA using DNA sequencing and bioinformatics analysis.

Results: TYR gene mutations were identified in 14 (app. 60%) albinism patients.

Conclusions: We found 10 mutations, 3 of which were novel. No mutation was found in our ocular albinism patients, but one of them was heterozygous for the p.R402Q polymorphism.

No MeSH data available.


Related in: MedlinePlus