A new type of oculocutaneous albinism with a novel OCA2 mutation

Lee, Sang Yoon; Byun, Jun Chul; Jang, Kyung Mi; Kim, Saeyoon; Hwang, Su-Kyeong

doi:10.12701/yujm.2020.00339

Cited by 2 publications

(2 citation statements)

References 16 publications

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“…Visual acuity is 2/10 in the OCA1B type. Another variant of OCA1 is temperature-sensitive OCA in which initially non-pigmented body hair is present but pigmented hair of hands and feet may develop with time due to temperatures difference between exposed and covered body parts [ 35 , 36 ].…”

Section: Clinical Features Of Different Oca Typesmentioning

confidence: 99%

Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review

Ullah

2022

Genes

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Oculocutaneous albinism (OCA) is an autosomal recessive syndromic and non-syndromic defect with deficient or a complete lack of the melanin pigment. The characteristics of OCA appears in skin, hair, and eyes with variable degree of pigmentation. Clinical manifestations of OCA include nystagmus, photophobia, reduced visual acuity, hypo-plastic macula, and iris trans-illumination. There are eight OCA types (OCA1–8) documented with non-syndromic characteristics. Molecular studies identified seven genes linked to the OCA phenotype (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, C10orf11, and DCT) and one locus (OCA5) in consanguineous and sporadic albinism. The complications of OCA result in skin cancer and variable syndromes such as Hermansky–Pudlak syndrome (HPS) Chediak–Higashi syndrome (CHS). In the Pakistani population, autosomal recessive non-syndromic OCA is common and is associated with a large number of consanguineous families, and mutations in genes of non-syndromic types are reported. This review highlights the updates on the genetic mutation of OCA genes reported from Pakistani families. Several studies reported the genetic mutations in OCA1, OCA2, OCA3, OCA4, and OCA6 albinism in Pakistani families. A locus, OCA5, was also reported from the Pakistani population, but the gene has not been identified. A new type of OCA8 was identified due to the DCT gene mutation, and it is also reviewed here.

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Section: Clinical Features Of Different Oca Typesmentioning

confidence: 99%

Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review

Ullah

2022

Genes

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“…Causative variants in OCA2 were found to be the most common in pediatric patients with OA/OCA in the United States, representing 28% of cases (Chan et al., 2023). OCA2 is involved in the transport of tyrosine, stabilizing the melanosome protein complexes, regulating the pH of melanosome and the glutathione metabolism, and maintaining the stability of tyrosinase, all of which are essential for melanin synthesis (Lee et al., 2021; Montoliu et al., 2014; Yuasa et al., 2007). The identified OCA2 pathogenic variants include missense/nonsense single nucleotide variants (SNVs), splicing variants, and small and large indels (Chan et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

Novel compound heterozygous mutations in OCA2 gene were identified in a Chinese family with oculocutaneous albinism

Jiang,

Zhang,

Kan

et al. 2023

Molec Gen & Gen Med

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BackgroundOculocutaneous albinism (OCA) is a group of rare autosomal recessive disorders characterized by clinical genetic heterogeneity. OCA type II (OMIM: 203200) is the most common subtype among African and African Americans, primarily caused by pathogenic variants in the OCA2 (HGNC ID: 8101) gene. In this study, we presented a Chinese family with OCA and reported two novel variants in the OCA2 gene.MethodsWhole‐exome sequencing (WES) was performed to identify pathogenic variants in the proband. The candidate variants were subsequently validated using Sanger sequencing and QPCR assay. Additionally, bioinformatics analyses were employed to predict the deleteriousness and conservation of the identified mutations.ResultsIn the 16‐year‐old male proband, two novel compound heterozygous OCA2 variants, NM_000275.3: c.1640T>G (NP_000266.2: p.L547R) and an exons 10‐19 deletion variant, were identified. Meanwhile, a reported heterozygous variant c.1441G>A/p.A481T (NM_000275.3, NP_000266.2) in the OCA2 gene was also found in the proband. Sanger sequencing confirmed that the two variants c.1441G>A/p.A481T and c.1640T>G/p.L547R were inherited from his father. Moreover, qPCR assay revealed that the exons 10‐19 deletion was inherited from the mother, his sister also carried this variant. Fortunately, the variant was not detected in the amniotic fluid of the proband's sister. Multiple online bioinformatics tools predicted the variant c.1640T>G to be damaging, leading to the replacement of a highly conserved leucine with an arginine. The gross exon 10‐19 deletion in the OCA2 gene resulted in a truncated, non‐functional protein losing the 3–9 transmembrane α‐helices domains. According to the American College of Medical Genetics and Genomics classification, these three variants in the OCA2 gene were evaluated as likely pathogenic.ConclusionThis study has identified two novel compound variants in the OCA2 gene and a previously reported variant in a Chinese family with OCA. By expanding the mutation spectrum of the OCA2 gene, our findings contribute to a better understanding of the genetic basis of OCA.

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A new type of oculocutaneous albinism with a novel OCA2 mutation

Cited by 2 publications

References 16 publications

Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review

Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review

Novel compound heterozygous mutations in OCA2 gene were identified in a Chinese family with oculocutaneous albinism

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