Asgharzade Samira, Reiisi Somayeh, Tabatabaiefar Mohammad Amin, Chaleshtori Morteza Hashemzadeh
Dept. of Molecular Medicine, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Cellular and Molecular Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran.
Iran J Public Health. 2017 Jan;46(1):76-82.
Hearing loss (HL) is the most frequent neurosensory impairment. HL is highly heterogeneous defect. This disorder affects 1 out of 500 newborns. This study aimed to determine the role of DFNB2 locus and frequency of gene mutations in a population from west of Iran.
Thirty families investigated in Shahrekord University of Medical Sciences in 2014, genetic linkage analysis via four short tandem repeat markers linked to was performed for two consanguineous families originating from Hamedan (family-13) and Chaharmahal-Bakhtiari (family-32) provinces of Iran, co-segregating autosomal recessive HL and showed no mutation in gene in our preliminary investigation. All 49 coding exons and exon- intron boundaries of the gene were amplified by PCR and analyzed using direct DNA sequencing.
Two of families displayed linkage to DFNB2. Family-13 segregated a homozygous missense mutation (c.6487G>A) in exon 48 that results in a p.G2163S amino acid substitution in C-terminal domain of the myosin VIIA protein. While family-32 segregated a homozygous nonsense mutation (c.448 C>T) in exon five, resulting in a premature truncation at amino acid position 150 (p.Arg150X) in the motor domain of this protein.
Mutation frequency of gene in different populations of Iran as well as cause of HL in most cases are still unknown and more extensive studies have to be done.
听力损失（HL）是最常见的神经感觉障碍。HL是一种高度异质性的缺陷。这种疾病影响每500名新生儿中的1名。本研究旨在确定DFNB2基因座在伊朗西部人群中的作用以及基因突变频率。
2014年在设拉子医科大学对30个家庭进行了调查，对来自伊朗哈马丹省（13号家庭）和恰哈马哈勒-巴赫蒂亚里省（32号家庭）的两个近亲家庭进行了与DFNB2相关的四个短串联重复标记的遗传连锁分析，这两个家庭共分离常染色体隐性HL，且在我们的初步调查中未发现该基因有突变。通过聚合酶链反应（PCR）扩增该基因的所有49个编码外显子和外显子-内含子边界，并使用直接DNA测序进行分析。
其中两个家庭显示与DFNB2连锁。13号家庭在外显子48中分离出一个纯合错义突变（c.6487G>A），导致肌球蛋白VIIA蛋白C末端结构域中的p.G2163S氨基酸替换。而32号家庭在外显子5中分离出一个纯合无义突变（c.448C>T），导致该蛋白运动结构域中第150位氨基酸（p.Arg150X）处提前截断。
伊朗不同人群中该基因的突变频率以及大多数情况下HL的病因仍然未知，必须进行更广泛的研究。
