Objective:The aim of this study is to analyze the mutation characteristics of GJB2 and SLC26A4 gene in patients with delayed non-syndromic hearing loss, which is beneficial to the early detection and intervention of delayed deafness. Methods:Sanger sequencing technology was used to detect two common genes in 139 patients with non-syndromic deafness, six hot spot mutations in GJB2 gene and SLC26A4 gene, and single heterozygous mutations found in GJB2 gene and SLC26A4 gene were detected by whole exome sequencing. Results:Among the 25 patients with deafness caused by GJB2 gene mutation, 12 of them passed universal newborn hearing screening and then developed delayed extremely severe hearing loss. The onset time of hearing loss was 6-48 months. All the genotypes were homozygous or compound heterozygous mutation of c. 235delC, especially genotype of GJB2 c. 235delC homozygous and c. 235delC/c. 299-300 delAT compound heterozygous mutations, and the CT manifestations were normal. Among the 42 patients with deafness caused by SLC26A4 gene mutation, 30 of them passed universal newborn hearing screening and developed delayed deafness. The onset time of hearing loss was three months to ten years old. Among them, the genotypes of 21 patients were compound heterozygous mutation, and 9 patients were homozygous mutation of c. 919-2A>G, especially genotypes were SLC26A4 c. 919-2A>G/c. 665G>T and c. 919-2A>G /c. 2027T>A compound heterozygous mutation. The CT findings of 19 cases showed single enlarged vestibular aqueduct, and 11 cases showed enlarged vestibular aqueduct with Mondini malformation. Conclusion:For the children who have passed universal newborn hearing screening, the genotypes detected are GJB2 c. 235delC homozygous, SLC26A4 c. 919-2A>G homozygous or compound heterozygous mutations, especially genotypes GJB2 c. 235delC homozygous, c. 235delC/c. 299-300delAT compound heterozygous mutations and SLC26A4 c. 919-2A>G/c. 665G>T and c. 919-2A>G/c. 2027T>A compound heterozygous mutation. Attention should be paid to the hearing problems of children all the time, and the possibility of delayed deafness in the future should be considered.
目的：分析迟发性非综合征性耳聋患者GJB2和SLC26A4基因突变特点，利于迟发性耳聋的早期发现和干预。 方法：应用Sanger测序技术对139例非综合征性耳聋患者的2个常见基因，即GJB2基因和SLC26A4基因的6个热点突变进行检测，对在GJB2基因和SLC26A4基因检测发现的单杂合突变再行全外显子检测。 结果：25例由GJB2基因突变致聋的患者，其中12例患者出生时通过听力筛查后发展为迟发性极重度聋，开始出现听力下降的时间为6~48个月，基因型均为c.235delC纯合或复合杂合突变，尤其基因型为GJB2 c.235delC纯合和c.235delC/ c.299-300delAT复合杂合突变，CT表现正常。42例由SLC26A4基因突变致聋的患者中，30例患者出生时通过了听力筛查，随后发展为迟发性耳聋，开始出现听力下降的时间为3个月~10岁。其中21例基因型为复合杂合突变，9例为c.919-2A>G纯合突变，尤其基因型为SLC26A4 c.919-2A>G/c.665G>T和c.919-2A>G/c.2027T>A复合杂合突变。19例CT表现为单独前庭导水管扩大，11例表现为前庭导水管扩大伴Mondini畸形。 结论：对于出生时通过了听力筛查，同时基因检测的基因型为GJB2 c.235delC纯合、SLC26A4 c.919-2A>G纯合或复合杂合突变，尤其基因型为GJB2 c.235delC纯合和c.235delC/c.299-300delAT复合杂合突变及SLC26A4 c.919-2A>G/c.665G>T和c.919-2A>G/c.2027T>A复合杂合突变者，应时刻关注听力问题，考虑后续有迟发性耳聋的可能。.
Keywords: GJB2 gene; SLC26A4 gene; genotype; non-syndromic hearing loss.
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