Monoallelic characteristic-bearing heterozygous L1053X in BRCA2 gene among Sudanese women with breast cancer

BMC Med Genet. 2017 Aug 16;18(1):85. doi: 10.1186/s12881-017-0448-x.


Background: Breast cancer (BC) is the most common type of cancer in women. Among many risk factors of BC, mutations in BRCA2 gene were found to be the primary cause in 5-10% of cases. The majority of deleterious mutations are frameshift or nonsense mutations. Most of the reported BRCA2 mutations are protein truncating mutations.

Methods: The study aimed to describe the pattern of mutations including single nucleotide polymorphisms (SNPs) and variants of the BRCA2 (exon11) gene among Sudanese women patients diagnosed with BC. In this study a specific region of BRCA2 exon 11 was targeted using PCR and DNA sequencing.

Results: Early onset cases 25/45 (55.6%) were premenopausal women with a mean age of 36.6 years. Multiparity was more frequent within the study amounting to 30 cases (66.6%), with a mean parity of 4.1. Ductal type tumor was the predominant type detected in 22 cases (48.8%) among the reported histotypes. A heterozygous monoallelic nonsense mutation at nucleotide 3385 was found in four patients out of 9, where TTA codon was converted into the stop codon TGA.

Conclusion: This study detected a monoallelic nonsense mutation in four Sudanese female patients diagnosed with early onset BC from different families. Further work is needed to demonstrate its usefulness in screening of BC.

Keywords: BRCA2; Breast cancer; Heterozygous; Monoallelic; Stop Codon; Sudanese patients.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Alleles*
  • Amino Acid Sequence
  • BRCA2 Protein / genetics*
  • Base Sequence
  • Breast Neoplasms / genetics*
  • Case-Control Studies
  • Codon, Nonsense
  • Exons
  • Female
  • Heterozygote
  • Humans
  • Middle Aged
  • Polymorphism, Single Nucleotide*
  • Premenopause
  • Sequence Analysis, DNA
  • Sudan / epidemiology


  • BRCA2 Protein
  • BRCA2 protein, human
  • Codon, Nonsense