Study on TYR gene variant from a pedigree with oculocutaneous albinism.
10.3760/cma.j.cn511374-20200609-00422
- VernacularTitle:一个眼皮肤白化病家系的
TYR基因变异研究
- Author:
Yingzhen ZHANG
1
;
Caihong JIN
;
Min GUO
;
Duofu LI
;
Lianming CHAI
;
Yang WU
;
Donglu LI
Author Information
1. Gansu Medical College, Pingliang, Gansu 744000, China. 1113662817@qq.com.
- Publication Type:Journal Article
- MeSH:
Albinism, Oculocutaneous/genetics*;
Consanguinity;
Heterozygote;
Humans;
Mutation;
Pedigree
- From:
Chinese Journal of Medical Genetics
2021;38(9):833-837
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE:To analyze gene variants in a Chinese pedigree with oculocutaneous albinism (OCA).
METHODS:Gene sequencing of the proband and his parents was performed using chip capture high-throughput sequencing and Sanger sequencing techniques, and PolyPhen-2, SIFT, MutationTaster, and FATHMM software were used to predict the function of new variants. At the same time,the pedigree and variant genes of 4 albinism patients from this pedigree were analyzed.
RESULTS:Sequencing results showed that the proband's TYR gene (NM_000372) has c.230G>A (p.Arg77Gln) and c.120_121insG (p.Asp42GlyfsTer35) compound heterozygous variants. The proband's father carries c.230G>A heterozygous variant, and the mother carries c.120_121insG heterozygous variant, indicating that the proband's two variants are from his father and mother. The former is a known missense variant, which can cause abnormal or loss of the original function of the protein polypeptide chain. The latter c.120_121insG(p.Asp42GlyfsTer35) is an unreported frameshift variant of the TYR gene subregion (EX1; CDS1). PolyPhen-2, SIFT, MutationTaster and FATHMM predictions are all prompted as "harmful variants". This variant caused the amino acid encoded protein to terminate prematurely, producing a truncated protein, which eventually formed a 76-amino acid short-type TYR protein instead of the 529-amino acid wild-type TYR protein. Through the pedigree analysis, the four patients in the pedigree are all of the same type of compound heterozygous variants, and the disease-causing genes are all from the patient's parents. They belong to a special form of consanguineous marriage within 5 generations.
CONCLUSION:The compound heterozygous variants of c.230G>A (p.Arg77Gln) and c.120_121insG (p.Asp42GlyfsTer35) of the TYR gene may underlie the disease in this pedigree. The gene sequencing results enrich the variant spectrum of the TYR gene, and has facilitated molecular diagnosis for the patient.
