advertisement

Topcon

Abstract #86222 Published in IGR 21-2

Genomic Characterization of TBK1 Duplication in Korean Normal-tension Glaucoma Patients

Kim MJ; Kim YW; Jeoung JW; Seong MW; Lee JS; Kim DM; Ahn JH; Song JY; Cho SI; Park SS; Kim JY
Journal of Glaucoma 2020; 29: 331-336


: PRéCIS: One (0.2%) of 418 Korean normal-tension glaucoma (NTG) patients had TBK1 duplication. The putative mechanism of TBK1 duplication in Korean NTG patients is the nonhomologous end-joining. PURPOSE: TBK1 duplication is a genomic cause of familial NTG. NTG accounts for up to 90% of primary open-angle glaucoma in Koreans, with genetic tendency. We aimed to investigate the prevalence of TBK1 duplication in Korean NTG patients and to identify their genomic structure and duplication mechanism. MATERIALS AND METHODS: We obtained DNA samples from 418 NTG patients and 195 healthy controls for evaluating TBK1 copy number variations using a semiquantitative polymerase chain reaction (PCR). The samples with TBK1 gene duplication were further confirmed using droplet digital PCR. The whole-genome sequencing of patient samples with duplications was performed to identify the accurate breakpoints and to elucidate the genomic structure. Ophthalmic evaluation and confirmation of TBK1 duplication using junction PCR were performed in families of positive patients. RESULTS: TBK1 duplication was found in 1 of 418 NTG cases (0.2%). The duplication range was from g.64,803,151 to g.64,927,214 (124,063 bp). It is the smallest region of overlapping duplication in TBK1. Any repetitive sequences were not found near the breakpoints of our case. Inserted sequences were found within the breakpoints. A brother and a niece of the positive case appeared the typical clinical features of NTG and shared the same TBK1 duplications with the index case. CONCLUSIONS: In Korea, the prevalence of TBK1 duplication was 0.2% and the smallest reported TBK1 duplication associated with NTG was found. The mechanism of TBK1 duplication was suggested to be nonhomologous end-joining while a previous report pointed out the mechanism of TBK1 duplications as nonallelic homologous recombination.

Departments of Laboratory Medicine.

Full article

Classification:

9.2.4 Normal pressure glaucoma (Part of: 9 Clinical forms of glaucomas > 9.2 Primary open angle glaucomas)
3.4.2 Gene studies (Part of: 3 Laboratory methods > 3.4 Molecular genetics)



Issue 21-2

Change Issue


advertisement

Topcon