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DNA Repair (Amst). 2018 Jan;61:17-24. doi: 10.1016/j.dnarep.2017.11.001. Epub 2017 Nov 8.

Diagnosis of Fanconi Anaemia by ionising radiation- or mitomycin C-induced micronuclei.

Author information

1
Radiobiology, Department of Radiation Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa; iThemba LABS - NRF, Somerset West, 7129, South Africa.
2
Division of Haematology and Oncology, Department of Paediatrics, Chris Hani Baragwanath Academic Hospital and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa.
3
Division of Haematology and Oncology, Department of Paediatrics, Charlotte Maxeke Johannesburg Academic Hospital and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa.
4
Center for Medical Genetics, Ghent University Hospital, Ghent 9000, Belgium; Cancer Research Institute Ghent (CRIG), Ghent University Hospital, Ghent 9000, Belgium.
5
Center for Medical Genetics, Ghent University Hospital, Ghent 9000, Belgium.
6
Center for Human Genetics, Cliniques Universitaires Saint-Luc & Human Molecular Genetics (GEHU), de Duve Institute - Université catholique de Louvain, Brussels 1200, Belgium.
7
Department of Pediatric Hematology and Oncology, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Brussels 1200, Belgium.
8
Radiobiology, Department of Basic Medical Sciences, Ghent University, Ghent 9000, Belgium.
9
iThemba LABS - NRF, Somerset West, 7129, South Africa.
10
Radiobiology, Department of Radiation Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa; iThemba LABS - NRF, Somerset West, 7129, South Africa; Cancer Research Institute Ghent (CRIG), Ghent University Hospital, Ghent 9000, Belgium; Radiobiology, Department of Basic Medical Sciences, Ghent University, Ghent 9000, Belgium. Electronic address: ans.baeyens@wits.ac.za.

Abstract

Fanconi Anaemia (FA) is an autosomal recessive disorder characterised by defects in DNA repair, associated with chromosomal instability and cellular hypersensitivity to DNA cross-linking agents such as mitomycin C (MMC). The FA repair pathway involves complex DNA repair mechanisms crucial for genomic stability. Deficiencies in DNA repair genes give rise to chromosomal radiosensitivity. FA patients have shown increased clinical radiosensitivity by exhibiting adverse normal tissue side-effects. The study aimed to investigate chromosomal radiosensitivity of homozygous and heterozygous carriers of FA mutations using three micronucleus (MN) assays. The G0 and S/G2MN assays are cytogenetic assays to evaluate DNA damage induced by ionising radiation in different phases of the cell cycle. The MMC MN assay detects DNA damage induced by a crosslinking agent in the G0 phase. Patients with a clinical diagnosis of FA and their parents were screened for the complete coding region of 20 FA genes. Blood samples of all FA patients and parents were exposed to ionising radiation of 2 and 4Gy. Chromosomal radiosensitivity was evaluated in the G0 and S/G2 phase. Most of our patients were homozygous for the founder mutation FANCG c.637_643delTACCGCC; p.(Tyr213Lysfs*6) while one patient was compound heterozygous for FANCG c.637_643delTACCGCC and FANCG c.1379G > A, p.(Gly460Asp), a novel missense mutation. Another patient was compound heterozygous for two deleterious FANCA mutations. In FA patients, the G0- and S/G2-MN assays show significantly increased chromosomal radiosensitivity and genomic instability. Moreover, chromosomal damage was significantly elevated in MMC treated FA cells. We also observed an increase in chromosomal radiosensitivity and genomic instability in the parents using 3 assays. The effect was significant using the MMC MN assay. The MMC MN assay is advantageous as it is less labour intense, time effective and has potential as a reliable alternative method for detecting FA patients from parents and controls.

KEYWORDS:

Chromosomal radiosensitivity; DNA repair; Fanconi Anaemia; Genomic instability; Radiosensitivity

PMID:
29154021
DOI:
10.1016/j.dnarep.2017.11.001
[Indexed for MEDLINE]

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