Genetic analyses of Vietnamese patients with oculocutaneous albinism. Issue 9 (23rd July 2022)

• Record Type: Journal Article
• Authors: Thuong, Ma Thi Huyen; Anh, Luong Thi Lan; Nhung, Vu Phuong; Ngoc, Tran Thi Bich; Lan, Hoang Thu; Phuong, Doan Kim; Ha, Nguyen Hai; Van Hai, Nong; Ton, Nguyen Dang
• Is Part Of: Journal of clinical laboratory analysis. Volume 36:Issue 9(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-23
• Subjects: HPS1 -- OCA2 -- oculocutaneous albinism -- TYR -- vietnamese -- WES; Diagnosis, Laboratory -- Periodicals; Medical laboratory technology -- Periodicals; 616
• DOI: 10.1002/jcla.24625
• Languages: English
• ISSNs: 0887-8013

Abstract

Abstract: Background: Oculocutaneous albinism (OCA) is an autosomal recessive disease with hypopigmentation in skin, hair, and eyes, causing by the complete absence or reduction of melanin in melanocytes. Many types of OCA were observed based on the mutation in different causing genes relating to albinism. OCA can occur in non‐syndromic and syndromic forms, where syndromic OCA coexists with additional systemic consequences beyond hypopigmentation and visual‐associated symptoms. Methods: We performed whole exome sequencing in seven affected individuals (P1‐P7) for mutation identification, and then, Sanger sequencing was used for verifications. Results: Among them, five patients (P1‐P5) have mutations on TYR gene including c.346C > T, c.929insC, c.115 T > C, and c.559_560ins25. The mutation on OCA2 and HPS1 genes was found in patient 6 (P6, OCA2 c.2323G > A) and patient 7 (P7, HPS1 c.972delC), respectively. Confirmation in parents (except the family of the elderly patient, P5) showed that the mother and the father in each family carried one of the variants that were detected in patients. Additionally, the effective genetic counseling was applied in the third pregnancy of a family with two OCA children (P1 and P2). Conclusion: To our best knowledge, this is the first case with a novel homozygous missense mutation (c.115 T > C, p.W39R) in the TYR gene. This study provides a broader spectrum of mutations linked to the oculocutaneous albinism, an additional scientific basis for diagnosis, and appropriate genetic counseling for risk couples. Abstract : Oculocutaneous albinism (OCA) is an autosomal recessive disease with hypopigmentation in skin, hair and eyes, causing by the complete absence or reduction of melanin in melanocytes. We performed whole exome sequencing in seven affected individuals (P1‐P7) for mutation identification. Among them, five patients (P1‐P5) have mutations on TYR gene, one (P6) in OCA2 and one (P7) in HPS1 . To our best knowledge, this is the first case with a homozygous missense mutation (c.115T>C, p.W39R) in the TYR gene. This study provides a broader spectrum of mutations linked to the oculocutaneous albinism, an additional scientific basis for diagnosis, and appropriate genetic counselling for risk couples.