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He D, Liu X, Yao T, Hu J, Zheng X, Tang L, Fan X. Oculocutaneous albinism type 4: Novel compound heterozygous mutations in the SLC45A2 gene in a Chinese case. Mol Genet Genomic Med 2024; 12:e2385. [PMID: 38337174 PMCID: PMC10858317 DOI: 10.1002/mgg3.2385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 12/13/2023] [Accepted: 01/16/2024] [Indexed: 02/12/2024] Open
Abstract
BACKGROUND Oculocutaneous albinism type 4 (OCA4) is a rare autosomal recessive disorder characterized by a reduction of pigmentation in skin, hair, and eyes, and OCA4 is mainly seen in the SLC45A2 gene variants. OBJECTIVE To report a Chinese patient suspected of oculocutaneous albinism and identify the causing mutation. METHODS Genomic DNA was extracted from the peripheral blood samples of the patient, his parents, and elder brother. Whole exome sequencing was performed in the family, and Sanger sequencing was then used to verify the mutations. RESULTS Compound heterozygous variants, c.1304C>A (p.S435Y) and c.301C>G (p.R101G) in SLC45A2 gene, were detected in the proband, which were inherited from his father and mother respectively. Based on the ACMG guidelines, we can interpret the c.1304C>A (p.S435Y) variant as a suspected pathogenic variant and the c.301C>G (p.R101G) variant as a clinically significant unspecified variant. The diagnosis of OCA4 is confirmed. CONCLUSION We firstly reported this case of OCA4 with the compound heterozygous variants in the SLC45A2 gene. Our findings further enrich the reservoir of SLC45A2 mutations in OCA4.
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Affiliation(s)
- Danyue He
- Department of DermatologyThe First Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiP.R. China
- Key Laboratory of Dermatology (Anhui Medical University), Ministry of EducationHefeiAnhuiP.R. China
- Key Laboratory of Major Autoimmune DiseasesHefeiAnhuiP.R. China
| | - Xiaonan Liu
- Department of DermatologyThe First Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiP.R. China
- Key Laboratory of Dermatology (Anhui Medical University), Ministry of EducationHefeiAnhuiP.R. China
- Key Laboratory of Major Autoimmune DiseasesHefeiAnhuiP.R. China
| | - Tianyu Yao
- Department of DermatologyThe First Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiP.R. China
- Key Laboratory of Dermatology (Anhui Medical University), Ministry of EducationHefeiAnhuiP.R. China
- Key Laboratory of Major Autoimmune DiseasesHefeiAnhuiP.R. China
| | - Jie Hu
- Department of DermatologyThe First Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiP.R. China
- Key Laboratory of Dermatology (Anhui Medical University), Ministry of EducationHefeiAnhuiP.R. China
- Key Laboratory of Major Autoimmune DiseasesHefeiAnhuiP.R. China
| | - Xiaodong Zheng
- Department of DermatologyThe First Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiP.R. China
- Key Laboratory of Dermatology (Anhui Medical University), Ministry of EducationHefeiAnhuiP.R. China
- Key Laboratory of Major Autoimmune DiseasesHefeiAnhuiP.R. China
| | - Lili Tang
- Department of DermatologyThe First Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiP.R. China
- Key Laboratory of Dermatology (Anhui Medical University), Ministry of EducationHefeiAnhuiP.R. China
- Key Laboratory of Major Autoimmune DiseasesHefeiAnhuiP.R. China
| | - Xing Fan
- Department of DermatologyThe First Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiP.R. China
- Key Laboratory of Dermatology (Anhui Medical University), Ministry of EducationHefeiAnhuiP.R. China
- Key Laboratory of Major Autoimmune DiseasesHefeiAnhuiP.R. China
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Evident hypopigmentation without other ocular deficits in Dutch patients with oculocutaneous albinism type 4. Sci Rep 2021; 11:11572. [PMID: 34078970 PMCID: PMC8172864 DOI: 10.1038/s41598-021-90896-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/05/2021] [Indexed: 02/04/2023] Open
Abstract
To describe the phenotype of Dutch patients with oculocutaneous albinism type 4 (OCA4), we collected data on pigmentation (skin, hair, and eyes), visual acuity (VA), nystagmus, foveal hypoplasia, chiasmal misrouting, and molecular analyses of nine Dutch OCA4 patients from the Bartiméus Diagnostic Center for complex visual disorders. All patients had severely reduced pigmentation of skin, hair, and eyes with iris transillumination over 360 degrees. Three unrelated OCA4 patients had normal VA, no nystagmus, no foveal hypoplasia, and no misrouting of the visual pathways. Six patients had poor visual acuity (0.6 to 1.0 logMAR), nystagmus, severe foveal hypoplasia and misrouting. We found two novel variants in the SLC45A2 gene, c.310C > T; (p.Pro104Ser), and c.1368 + 3_1368 + 9del; (p.?). OCA4 patients of this Dutch cohort all had hypopigmentation of skin, hair, and iris translucency. However, patients were either severely affected with regard to visual acuity, foveal hypoplasia, and misrouting, or visually not affected at all. We describe for the first time OCA4 patients with an evident lack of pigmentation, but normal visual acuity, normal foveal development and absence of misrouting. This implies that absence of melanin does not invariably lead to foveal hypoplasia and abnormal routing of the visual pathways.
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Bibi N, Ullah A, Darwesh L, Khan W, Khan T, Ullah K, Khan B, Ahmad W. Identification and Computational Analysis of Novel TYR and SLC45A2 Gene Mutations in Pakistani Families With Identical Non-syndromic Oculocutaneous Albinism. Front Genet 2020; 11:749. [PMID: 32849781 PMCID: PMC7385404 DOI: 10.3389/fgene.2020.00749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/23/2020] [Indexed: 12/19/2022] Open
Abstract
Non-syndromic oculocutaneous albinism (nsOCA) is an inherited disorder of melanin biosynthesis with autosomal recessive mode of inheritance, presenting either hypopigmented or depigmented skin, hair, and eyes. It is genetically heterogeneous with seven loci (OCA1–OCA7) reported to date. In the present study, we have reported three consanguineous families (A, B, C) presenting identical nsOCA phenotypes. Sanger sequencing revealed a novel [NM_000372.5: c.826 T > C, p.(Cys276Arg)] and a recurrent variant [NM_000372.5: c.832C > T, p.(Arg278∗)] in tyrosinase (TYR) in families A and B, respectively. Microsatellite marker-based homozygosity mapping linked family C to OCA4. Sequence analysis identified a novel insertion variant (NM_016180.5: c.1331_1332insA) in the SLC45A2. Further, in silico mutagenesis and dynamic simulation approaches revealed that a novel Cys276Arg variant abolished the cysteine bridge and might contribute toward decreased stability of the TYR protein. Our study expands the mutation spectrum of the TYR and SLC45A2 genes and emphasizes that molecular investigations are essential for accurate disease diagnosis.
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Affiliation(s)
- Nousheen Bibi
- Department of Bioinformatics, Shaheed Benazir Bhutto Women University, Peshawar, Pakistan
| | - Asmat Ullah
- Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan.,Department of Molecular Biology, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Lubna Darwesh
- Department of Biochemistry, Hazara University, Mansehra, Pakistan
| | - Waqas Khan
- Department of Biochemistry, Hazara University, Mansehra, Pakistan
| | - Tanzeela Khan
- Department of Bioinformatics, Shaheed Benazir Bhutto Women University, Peshawar, Pakistan
| | - Kalim Ullah
- Department of Zoology, Kohat University of Science and Technology, Kohat, Pakistan
| | - Bushra Khan
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Wasim Ahmad
- Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan
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Gul H, Shah AH, Harripaul R, Mikhailov A, Prajapati K, Khan E, Ullah F, Zubair M, Ali MZ, Shah AH, Salman S, Khan S, Vincent JB, Khan MA. Genetic studies of multiple consanguineous Pakistani families segregating oculocutaneous albinism identified novel and reported mutations. Ann Hum Genet 2019; 83:278-284. [PMID: 30868578 DOI: 10.1111/ahg.12307] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 02/05/2019] [Accepted: 02/18/2019] [Indexed: 11/28/2022]
Abstract
Oculocutaneous albinism (OCA) is an autosomal-recessive disorder of a defective melanin pathway. The condition is characterized by hypopigmentation of hair, dermis, and ocular tissue. Genetic studies have reported seven nonsyndromic OCA genes, among which Pakistani OCA families mostly segregate TYR and OCA2 gene mutations. Here in the present study, we investigate the genetic factors of eight consanguineous OCA families from Pakistan. Genetic analysis was performed through single-nucleotide polymorphism (SNP) genotyping (for homozygosity mapping), whole exome sequencing (for mutation identification), Sanger sequencing (for validation and segregation analysis), and quantitative PCR (qPCR) (for copy number variant [CNV] validation). Genetic mapping in one family identified a novel homozygous deletion mutation of the entire TYRP1 gene, and a novel deletion of exon 19 in the OCA2 gene in two apparently unrelated families. In three further families, we identified homozygous mutations in TYR (NM_000372.4:c.1424G > A; p.Trp475*), NM_000372.4:c.895C > T; p.Arg299Cys), and SLC45A2 (NM_016180:c.1532C > T; p.Ala511Val). For the remaining two families, G and H, compound heterozygous TYR variants NM_000372.4:c.1037-7T > A, NM_000372.4:c.1255G > A (p.Gly419Arg), and NM_000372.4:c.1255G > A (p.Gly419Arg) and novel variant NM_000372.4:c.248T > G; (p.Val83Gly), respectively, were found. Our study further extends the evidence of TYR and OCA2 as genetic mutation hot spots in Pakistani families. Genetic screening of additional OCA cases may also contribute toward the development of Pakistani specific molecular diagnostic tests, genetic counseling, and personalized healthcare.
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Affiliation(s)
- Hadia Gul
- Department of Biological Sciences, Faculty of Sciences, Gomal University, D.I. Khan, Pakistan
| | - Abdul Haleem Shah
- Department of Biological Sciences, Faculty of Sciences, Gomal University, D.I. Khan, Pakistan
| | - Ricardo Harripaul
- Molecular Neuro-Psychiatry and Development Lab (MiND), Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada
| | - Anna Mikhailov
- Molecular Neuro-Psychiatry and Development Lab (MiND), Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada
| | - Kamalben Prajapati
- Molecular Neuro-Psychiatry and Development Lab (MiND), Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada
| | - Ejazullah Khan
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
| | - Farman Ullah
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
| | - Muhammad Zubair
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan.,Department of Cell and Developmental Biology, School of Life Sciences, University of Science and Technology, Hefei, China
| | - Muhammad Zeeshan Ali
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
| | - Ayesha Haleem Shah
- Department of Biological Sciences, Faculty of Sciences, Gomal University, D.I. Khan, Pakistan
| | - Said Salman
- Department of Plant Breeding and Genetics, Ghazi University, D.G. Khan, Pakistan
| | - Saadullah Khan
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology, Kohat, Pakistan
| | - John B Vincent
- Molecular Neuro-Psychiatry and Development Lab (MiND), Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Muzammil Ahmad Khan
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
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Shahzad M, Yousaf S, Waryah YM, Gul H, Kausar T, Tariq N, Mahmood U, Ali M, Khan MA, Waryah AM, Shaikh RS, Riazuddin S, Ahmed ZM. Molecular outcomes, clinical consequences, and genetic diagnosis of Oculocutaneous Albinism in Pakistani population. Sci Rep 2017; 7:44185. [PMID: 28266639 PMCID: PMC5339803 DOI: 10.1038/srep44185] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 02/03/2017] [Indexed: 12/31/2022] Open
Abstract
Nonsyndromic oculocutaneous Albinism (nsOCA) is clinically characterized by the loss of pigmentation in the skin, hair, and iris. OCA is amongst the most common causes of vision impairment in children. To date, pathogenic variants in six genes have been identified in individuals with nsOCA. Here, we determined the identities, frequencies, and clinical consequences of OCA alleles in 94 previously unreported Pakistani families. Combination of Sanger and Exome sequencing revealed 38 alleles, including 22 novel variants, segregating with nsOCA phenotype in 80 families. Variants of TYR and OCA2 genes were the most common cause of nsOCA, occurring in 43 and 30 families, respectively. Twenty-two novel variants include nine missense, four splice site, two non-sense, one insertion and six gross deletions. In vitro studies revealed retention of OCA proteins harboring novel missense alleles in the endoplasmic reticulum (ER) of transfected cells. Exon-trapping assays with constructs containing splice site alleles revealed errors in splicing. As eight alleles account for approximately 56% (95% CI: 46.52–65.24%) of nsOCA cases, primarily enrolled from Punjab province of Pakistan, hierarchical strategies for variant detection would be feasible and cost-efficient genetic tests for OCA in families with similar origin. Thus, we developed Tetra-primer ARMS assays for rapid, reliable, reproducible and economical screening of most of these common alleles.
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Affiliation(s)
- Mohsin Shahzad
- Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Sairah Yousaf
- Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, USA.,Institute of Molecular Biology &Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | - Yar M Waryah
- Molecular Biology &Genetics Department, Medical Research Center, Liaquat University of Medical &Health Sciences, Jamshoro, Pakistan
| | - Hadia Gul
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
| | - Tasleem Kausar
- Institute of Molecular Biology &Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | - Nabeela Tariq
- Institute of Molecular Biology &Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | - Umair Mahmood
- Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Muhammad Ali
- Government College University, Faisalabad, Pakistan
| | - Muzammil A Khan
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
| | - Ali M Waryah
- Molecular Biology &Genetics Department, Medical Research Center, Liaquat University of Medical &Health Sciences, Jamshoro, Pakistan
| | - Rehan S Shaikh
- Institute of Molecular Biology &Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Zubair M Ahmed
- Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, USA
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