Clonality analysis and IDH1 and IDH2 mutation detection in both components of dedifferentiated chondrosarcoma, implicated its monoclonal origin

Abstract Background India accounts for 20% of the global retinoblastoma (RB) burden. However, the existing data on RB1 gene germline mutations and its influence on clinical decisions is minimally explored. Methods Fifty children with RB underwent complete clinical examination and appropriate multidisciplinary management. Screening of germline RB1 gene mutations was performed through next-generation sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA) analysis. The mutation and non-mutation groups were compared for clinical parameters especially severity, progression and recurrence. Results Twenty-nine patients had bilateral RB (BLRB) and 21 had unilateral RB (ULRB). The genetic analysis revealed 20 RB1 variations in 29 probands, inclusive of 3 novel mutations, known 16 mutations and heterozygous whole gene deletions. The mutation detection rate (MDR) was 86.2% in BLRB and 19% in ULRB. Associations of disease recurrence (p = 0.021), progression (p = 0.000) and higher percentage of optic nerve invasion, subretinal seeds and high-risk pathological factors were observed in the mutation group. Clinical management was influenced by the presence of germline mutations, particularly while deciding on enucleation, frequency of periodic follow up and radiotherapy. Conclusions We identified novel RB1 mutations, and our mutation detection rate was on par with the previous global studies. In our study, genetic results influenced clinical management and we suggest that it should be an essential and integral component of RB-care in India and elsewhere.

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Diverse Genetic Landscape of Suspected Retinitis Pigmentosa in a Large Korean Cohort

Genes ◽

10.3390/genes12050675 ◽

2021 ◽

Vol 12 (5) ◽

pp. 675

Author(s):

Yoon-Jeon Kim ◽

You-Na Kim ◽

Young-Hee Yoon ◽

Eul-Ju Seo ◽

Go-Hun Seo ◽

...

Keyword(s):

Retinitis Pigmentosa ◽

Detection Rate ◽

Mutation Detection ◽

Retinal Disease ◽

Mutation Detection Rate ◽

Targeted Next Generation Sequencing ◽

Initial Symptoms ◽

Genetic Landscape ◽

History Of ◽

Genetic Profiles

We conducted targeted next-generation sequencing (TGS) and/or whole exome sequencing (WES) to assess the genetic profiles of clinically suspected retinitis pigmentosa (RP) in the Korean population. A cohort of 279 unrelated Korean patients with clinically diagnosed RP and available family members underwent molecular analyses using TGS consisting of 88 RP-causing genes and/or WES with clinical variant interpretation. The combined genetic tests (TGS and/or WES) found a mutation in the 44 RP-causing genes and seven inherited retinal disease (IRD)-causing genes, and the total mutation detection rate was 57%. The mutation detection rate was higher in patients who experienced visual deterioration at a younger age (75.4%, age of symptom onset under 10 years) and who had a family history of RP (70.7%). The most common causative genes were EYS (8.2%), USH2A (6.8%), and PDE6B (4.7%), but mutations were dispersed among the 51 RP/IRD genes generally. Meanwhile, the PDE6B mutation was the most common in patients experiencing initial symptoms in their first decade, EYS in their second to third decades, and USH2A in their fifth decades and older. Of note, WES revealed some unexpected genotypes: ABCC6, CHM, CYP4V2, RS1, TGFBI, VPS13B, and WDR19, which were verified by ophthalmological re-phenotyping.

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