Tóth Tímea, Kupka Susan, Blin Nicolaus, Pfister Markus, Sziklai István
Debreceni Egyetem Orvos- és Egészségtudományi Centrum, Altalános Orvostudományi Kar Fül-orr-gégeklinika, Debrecen.
Orv Hetil. 2002 Oct 6;143(40):2285-9.
Hereditary hearing impairment is a heterogeneous disorder showing different pattern of inheritance and involving a multitude of different genes. Mutations in the GJB2 gene, especially the 35delG mutation, have been established as a major cause of inherited and sporadic non-syndromic deafness in different populations. Mutations in GJB2 gene, encoding gap junction protein (Connexin 26), may be responsible for up to 50% of cases of autosomal recessive non-syndromic hearing impairment and in 15-30% of sporadic cases.
The authors analyzed 15 north east Hungarian families and 30 sporadic cases with nonsyndromic hearing impairment for the 35delG mutation.
DNA were tested for the common 35delG mutation by a polymerase chain reaction based restriction enzyme assay (BsiYl).
Fifty two patients showing a homozygous 35delG mutation were audiological examined. Ordinarily these patients showed a prelingual, sensorineural, bilateral, symmetric hearing loss without progression. The audiograms were characterized by sloping or flat patterns. The carrier frequency of the 35delG mutation among control group was 5.1%.
The phenotypic manifestation varied in 30% of all analyzed patients, making genetic counseling extremely difficult. Due to this knowledge mutation analysis of GJB2 cannot distinctly predict the degree of hearing impairment.
遗传性听力障碍是一种异质性疾病，表现出不同的遗传模式，涉及众多不同基因。GJB2基因的突变，尤其是35delG突变，已被确认为不同人群中遗传性和散发性非综合征性耳聋的主要原因。编码缝隙连接蛋白（连接蛋白26）的GJB2基因突变可能导致高达50%的常染色体隐性非综合征性听力障碍病例以及15% - 30%的散发病例。
作者分析了15个匈牙利东北部家庭以及30例患有非综合征性听力障碍的散发病例，检测其中的35delG突变。
采用基于聚合酶链反应的限制性酶切分析（BsiYl）检测DNA中的常见35delG突变。
对52例显示纯合35delG突变的患者进行了听力学检查。通常这些患者表现为语前、感音神经性、双侧对称的听力损失且无进展。听力图的特征为斜坡型或平坦型。对照组中35delG突变的携带频率为5.1%。
在所有分析的患者中，30%的患者表型表现各异，这使得遗传咨询极为困难。基于这一认识，GJB2基因的突变分析无法明确预测听力障碍的程度。
