Çağrı GÜLEÇ, Ayça Dilruba ASLANGER, Volkan KARAMAN, Bernd WOLLNİK, Fatih TEPGEÇ, Hülya KAYSERİLİ, Oya UYGUNER

GJB2 İLİŞKİLİ NON-SENDROMİK İŞİTME KAYBI VARYANTLARININ SPEKTRUMU VE TÜRK TOPLUMUNDAKİ SIKLIKLARI

Amaç: İşitme kaybı, çocukluk çağındaki en önemli kronik sağlık sorunlarından biridir ve yaşam kalitesini konuşma, eğitim ve sosyal ilişki sorunlarına yol açarak azaltır. Özellikle non-sendromik işitme kaybında genetik faktörlerin rolü etkilenmiş kişi ve ailelerinin genetik tanı ve genetik danışma aşamalarında doğru yönlendirilmesi açısından kilit bir rol oynar. Bu nedenle, non-sendromik işitme kaybı olan hasta ve ailelerinin önümüzdeki yıllarda genetik tanı ve danışmasına katkıda bulunmak amacıyla, bu çalışmada, 2002-2021 yılları arasında sinirsel tip işitme kaybı tanısı alan hastalardaki GJB2 gen varyantlarını ve sıklıklarını sunmaya çalıştık. Gereç ve Yöntem: GJB2 geninin iki ekzonu, 402 hasta DNA’sında iki ayrı PCR ile çoğaltıldı ve Sanger yöntemi ile dizilendi. Bulgular: Non-sendromik işitme kaybı olan olguların %35’inde (141/402) GJB2 geninde 13 farklı değişim saptadık. Hastaların %53,9’u en yaygın (%59,21) varyant olan c.35delG değişimini homozigot taşırken, %33,3’ü birleşik heterozigot olarak taşıyordu. Yaklaşık %13’ünde ise değişim heterozigot olarak belirlendi. Çalışma grubumuzda en yaygın GJB2 varyantı olan c.35delG değişimini sırasıyla c.71G>A (%6,38), c.-23+1G>A (%3,54) ve c.233delG (%2,48) değişimleri izlemiştir. Keratit-ihtiyoz-sağırlık (KID) ve palmoplantar keratoderma (PPK) sendromu tanılı sekiz hastanın dördünde heterozigot p.Asp50Glu (c.150C>A) değişimi saptandı. Sonuç: Sonuçlarımız, Türkiye’deki non-sendromik işitme kaybı hastalarındaki c.35delG varyantının uzun zamandır bilinen baskınlığını bir kez daha göstermektedir. Ayrıca, tek mutant alelsaptanan hastaların oranı, non-sendromik işitme kaybının alelik heterojenitesi nedeniyle rastlantısal olarak değerlendirilebileceği gibi, digenik kalıtımı da düşündürebilir

Anahtar Kelimeler:

Sinirsel tip işitme kaybı, GJB2 geni, c.35delG değişimi, mutasyon sıklığı

GJB2-RELATED NON-SYNDROMIC HEARING LOSS VARIANTS’ SPECTRUM AND THEIR FREQUENCY IN TURKISH POPULATION

Objective: Hearing loss (HL) is one of the most prevalent chronic conditions in children and has consequences in speech, language, education, and social functioning which impede the quality of life. Due to the major involvement of the genetic factors in HL, especially non-syndromic HL (NSHL), genetic diagnosis and genetic counseling have a major impact on early management of the affected individuals and their families. Herein, we report the GJB2 gene variants and their frequencies in NSHL cohort at a tertiary health center between 2002-2021 to contribute for the future genetic counseling of Turkish NSHL patients. Materials and Methods: Two exons of the GJB2 gene were amplified in 402 NSHL patients by two separate PCR reactions and sequenced using the Sanger technique. Results: We found 13 different GJB2 variants in 35% (141/402) of the patients with NSHL. 53.9% were homozygous and 33.3% were compound heterozygous for the most common (59.21%) variant, c.35delG. Approximately 13% of the patients were found to carry the variants in the heterozygous state. The most frequent GJB2 variant c.35delG was followed by c.71G>A (6.38%), c.-23+1G>A (3.54%) and c.233delG (2.48%). We found heterozygous p.Asp50Glu (c.150C>A) alteration in four of eight patients with keratitis, ichthyosis, deafness (KID) and palmoplantar keratoderma (PPK) syndrome. Conclusion: Our results further emphasize the well-known prevalance of the GJB2 c.35delG alteration being the most predominant variant in the Turkish NSHL patients. The high rate of mono-allelic state could be considered as coincidental due to high allelic heterogeneity of NSHL, or possibly suggestive for digenic inheritance.

Keywords:

Sensorineural hearing loss, GJB2 gene, c.35delG alteration, mutation frequency,

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1. Kelsell DP, Dunlop J, Stevens HP, Lench NJ, Liang JN, Parry G, et al. Connexin 26 mutations in hereditary non-syndromic sensorineural deafness. Nature 1997;387(6628):80-3. [CrossRef]
2. Tekin M, Arnos KS, Pandya A. Advances in hereditary deafness. Lancet 200;358(9287):1082-90. [CrossRef]
3. Lautermann J, ten Cate WJ, Altenhoff P, Grümmer R, Traub O, Frank H, et al. Expression of the gap-junction connexins 26 and 30 in the rat cochlea. Cell Tissue Res 1998;294(3):415- 20. [CrossRef]
4. Forge A, Becker D, Casalotti S, Edwards J, Marziano N, Nevill G. Gap junctions in the inner ear: comparison of distribution patterns in different vertebrates and assessement of connexin composition in mammals. J Comp Neurol 2003;8;467(2):207-31. [CrossRef]
5. Zhao HB, Yu N. Distinct and gradient distributions of connexin26 and connexin30 in the cochlear sensory epithelium of guinea pigs. J Comp Neurol 2006;20;499(3):506-18. [CrossRef]
6. Majumder P, Crispino G, Rodriguez L, Ciubotaru CD, Anselmi F, Piazza V, et al. ATP-mediated cell-cell signaling in the organ of Corti: the role of connexin channels. Purinergic Signal 2010;6(2):167-87. [CrossRef]
7. Caceres-Rios H, Tamayo-Sanchez L, Duran-Mckinster C, de la Luz Orozco M, Ruiz-Maldonado R. Keratitis, ichthyosis, and deafness (KID syndrome): review of the literature and proposal of a new terminology. Pediatr Dermatol 1996;13(2):105-13. [CrossRef]
8. Cryns K, Orzan E, Murgia A, Huygen PL, Moreno F, del Castillo I, et al. A genotype-phenotype correlation for GJB2 (connexin 26) deafness. J Med Genet 2004;41(3):147-54. [CrossRef]
9. Meşe G, Londin E, Mui R, Brink PR, White TW. Altered gating properties of functional Cx26 mutants associated with recessive non-syndromic hearing loss. Hum Genet 2004;115(3):191-9. [CrossRef]
10. Beltramello M, Piazza V, Bukauskas FF, Pozzan T, Mammano F. Impaired permeability to Ins(1,4,5)P3 in a mutant connexin underlies recessive hereditary deafness. Nat Cell Biol 2005;7(1):63-9. [CrossRef]
11. Lee JR, Derosa AM, White TW. Connexin mutations causing skin disease and deafness increase hemichannel activity and cell death when expressed in Xenopus oocytes. J Invest Dermatol 2009;129(4):870-8. [CrossRef]
12. Gasparini P, Rabionet R, Barbujani G, Melçhionda S, Petersen M, Brøndum-Nielsen K, et al. High carrier frequency of the 35delG deafness mutation in European populations. Genetic Analysis Consortium of GJB2 35delG. Eur J Hum Genet 2000;8(1):19-23. [CrossRef]
13. Safka Brozkova D, Uhrova Meszarosova A, Lassuthova P, Varga L, Staněk D, Borecká S, et al. The Cause of Hereditary Hearing Loss in GJB2 Heterozygotes-A Comprehensive Study of the GJB2/DFNB1 Region. Genes (Basel) 2021;1;12(5):684. [CrossRef]
14. Hegde S, Hegde R, Kulkarni SS, Das KK, Gai PB, Bulgouda R. Molecular alteration in the Gap Junction Beta 2 (GJB2) gene associated with non-syndromic sensorineural hearing impairment. Intractable Rare Dis Res 2021;10(1):31-6. [CrossRef]
15. Mani RS, Ganapathy A, Jalvi R, Srikumari Srisailapathy CR, Malhotra V, Chadha S, et al. Functional consequences of novel connexin 26 mutations associated with hereditary hearing loss. Eur J Hum Genet 2009;17(4):502-9. [CrossRef]
16. Wu CC, Tsai CH, Hung CC, Lin YH, Lin YH, Huang FL, et al. Newborn genetic screening for hearing impairment: a population-based longitudinal study. Genet Med 2017;19(1):6-12. [CrossRef]
17. Morgan A, Lenarduzzi S, Spedicati B, Cattaruzzi E, Murru FM, Pelliccione G, et al. Lights and Shadows in the Genetics of Syndromic and Non-Syndromic Hearing Loss in the Italian Population. Genes (Basel) 2020;22;11(11):1237. [CrossRef]
18. Pandya A, O’Brien A, Kovasala M, Bademci G, Tekin M, Arnos KS. Analyses of del(GJB6-D13S1830) and del(GJB6-D13S1834) deletions in a large cohort with hearing loss: Caveats to interpretation of molecular test results in multiplex families. Mol Genet Genomic Med 2020;8(4):e1171. [CrossRef]
19. Bazazzadegan N, Nikzat N, Fattahi Z, Nishimura C, Meyer N, Sahraian S, et al. The spectrum of GJB2 mutations in the Iranian population with non-syndromic hearing loss--a twelve year study. Int J Pediatr Otorhinolaryngol 2012;76(8):1164-74. [CrossRef]
20. Gardner P, Oitmaa E, Messner A, Hoefsloot L, Metspalu A, Schrijver I. Simultaneous multigene mutation detection in patients with sensorineural hearing loss through a novel diagnostic microarray: a new approach for newborn screening follow-up. Pediatrics 2006;118(3):985-94. [CrossRef]
21. Prasad S, Cucci RA, Green GE, Smith RJ. Genetic testing for hereditary hearing loss: connexin 26 (GJB2) allele variants and two novel deafness-causing mutations (R32C and 645-648delTAGA). Hum Mutat 2000;16(6):502-8. [CrossRef]
22. Buonfiglio P, Bruque CD, Luce L, Giliberto F, Lotersztein V, Menazzi S, et al. GJB2 and GJB6 Genetic Variant Curation in an Argentinean Non-Syndromic Hearing-Impaired Cohort. Genes (Basel) 2020;11(10):1233. [CrossRef]
23. Riahi Z, Zainine R, Mellouli Y, Hannachi R, Bouyacoub Y, Laroussi N, et al. Compound heterozygosity for dominant and recessive GJB2 mutations in a Tunisian family and association with successful cochlear implant outcome. Int J Pediatr Otorhinolaryngol 2013;77(9):1481-4. [CrossRef]
24. Duman D, Tekin M. Autosomal recessive nonsyndromic deafness genes: a review. Front Biosci (Landmark Ed) 2012;17:2213-36. [CrossRef]
25. Kelley PM, Harris DJ, Comer BC, Askew JW, Fowler T, Smith SD, et al. Novel mutations in the connexin 26 gene (GJB2) that cause autosomal recessive (DFNB1) hearing loss. Am J Hum Genet 1998;62(4):792-9. [CrossRef]
26. Batissoco AC, Abreu-Silva RS, Braga MC, Lezirovitz K, Della- Rosa V, Alfredo T Jr, et al. Prevalence of GJB2 (connexin-26) and GJB6 (connexin-30) mutations in a cohort of 300 Brazilian hearing-impaired individuals: implications for diagnosis and genetic counseling. Ear Hear 2009;30(1):1-7. [CrossRef]
27. Dalamon V, Fiori MC, Figueroa VA, Oliva CA, Del Rio R, Gonzalez W, et al. Gap-junctional channel and hemichannel activity of two recently identified connexin 26 mutants associated with deafness. Pflugers Arch 2016;468(5):909-18. [CrossRef]
28. Amorini M, Romeo P, Bruno R, Galletti F, Di Bella C, Longo P, et al. Prevalence of Deafness-Associated Connexin-26 (GJB2) and Connexin-30 (GJB6) Pathogenic Alleles in a Large Patient Cohort from Eastern Sicily. Ann Hum Genet 2015;79(5):341-9. [CrossRef]
29. Mahdieh N, Rabbani B. Statistical study of 35delG mutation of GJB2 gene: a meta-analysis of carrier frequency. Int J Audiol 2009;48(6):363-70. [CrossRef]
30. Azadegan-Dehkordi F, Ahmadi R, Koohiyan M, Hashemzadeh-Chaleshtori M. Update of spectrum c.35delG and c.-23+1G>A mutations on the GJB2 gene in individuals with autosomal recessive nonsyndromic hearing loss. Ann Hum Genet 2019;83(1):1-10. [CrossRef]
31. Tekin M, Duman T, Boğoçlu G, Incesulu A, Comak E, Ilhan I, et al. Spectrum of GJB2 mutations in Turkey comprises both Caucasian and Oriental variants: roles of parental consanguinity and assortative mating. Hum Mutat 2003;21(5):552-3. [CrossRef]
32. Subaşıoğlu A, Duman D, Sırmacı A, Bademci G, Carkıt F, Somdaş MA, et al. Research of genetic bases of hereditary non-syndromic hearing loss. Turk Pediatri Ars 2017;1;52(3):122-32. [CrossRef]
33. Uyguner O, Emiroglu M, Uzumcu A, Hafiz G, Ghanbari A, Baserer N, et al. Frequencies of gap- and tight-junction mutations in Turkish families with autosomal-recessive nonsyndromic hearing loss. Clin Genet 2003;64(1):65-9. [CrossRef]
34. Liu XZ, Yuan Y, Yan D, Ding EH, Ouyang XM, Fei Y, et al. Digenic inheritance of non-syndromic deafness caused by mutations at the gap junction proteins Cx26 and Cx31. Hum Genet 2009;125(1):53-62. [CrossRef]
35. Asma A, Ashwaq A, Norzana AG, Atmadini AM, Ruszymah BH, Saim L, et al. The association between GJB2 mutation and GJB6 gene in non syndromic hearing loss school children. Med J Malaysia 2011;66(2):124-8.
36. Rodriguez-Paris J, Schrijver I. The digenic hypothesis unraveled: the GJB6 del(GJB6-D13S1830) mutation causes allele-specific loss of GJB2 expression in cis. Biochem Biophys Res Commun 2009;13;389(2):354-9. [CrossRef]
37. Naseri M, Akbarzadehlaleh M, Masoudi M, Ahangari N, Poursadegh Zonouzi AA, Poursadegh Zonouzi A, et al. Genetic Linkage Analysis of DFNB4, DFNB28, DFNB93 Loci in Autosomal Recessive Non-syndromic Hearing Loss: Evidence for Digenic Inheritance in GJB2 and GJB3 Mutations. Iran J Public Health 2018;47(1):95-102.
38. Kim SY, Kim AR, Kim NKD, Lee C, Kim MY, Jeon EH, et al. Unraveling of Enigmatic Hearing-Impaired GJB2 Single Heterozygotes by Massive Parallel Sequencing: DFNB1 or Not? Medicine (Baltimore) 2016;95(14):e3029. [CrossRef]
39. Lechowicz U, Pollak A, Oziębło D, Ołdak M. Pathogenic p.Cys194Metfs*17 variant argues against TMPRSS3/ GJB2 digenic inheritance of hearing loss. Eur Arch Otorhinolaryngol 2016;273(5):1327-8. [CrossRef]
40. Kooshavar D, Tabatabaiefar MA, Farrokhi E, Abolhasani M, Noori-Daloii MR, Hashemzadeh-Chaleshtori M. Digenic inheritance in autosomal recessive non-syndromic hearing loss cases carrying GJB2 heterozygote mutations: assessment of GJB4, GJA1, and GJC3. Int J Pediatr Otorhinolaryngol 2013;77(2):189-93. [CrossRef]
41. Ołdak M, Lechowicz U, Pollak A, Oziębło D, Skarżyński H. Overinterpretation of high throughput sequencing data in medical genetics: first evidence against TMPRSS3/ GJB2 digenic inheritance of hearing loss. J Transl Med 2019;14;17(1):269. [CrossRef]
42. Richard G, Brown N, Ishida-Yamamoto A, Krol A. Expanding the phenotypic spectrum of Cx26 disorders: Bart-Pumphrey syndrome is caused by a novel missense mutation in GJB2. J Invest Dermatol 2004;123(5):856-63. [CrossRef]
43. Essenfelder GM, Bruzzone R, Lamartine J, Charollais A, Blanchet-Bardon C, Barbe MT, et al. Connexin30 mutations responsible for hidrotic ectodermal dysplasia cause abnormal hemichannel activity. Hum Mol Genet 2004;15;13(16):1703-14. [CrossRef]
44. Shearer AE, Smith RJ. Massively Parallel Sequencing for Genetic Diagnosis of Hearing Loss: The New Standard of Care. Otolaryngol Head Neck Surg 2015;153(2):175-82. [CrossRef]
45. Sloan-Heggen CM, Bierer AO, Shearer AE, Kolbe DL, Nishimura CJ, Frees KL, et al. Comprehensive genetic testing in the clinical evaluation of 1119 patients with hearing loss. Hum Genet 2016;135(4):441-50. [CrossRef]