Rare Cases of IDH1 Mutations in Spinal Cord Astrocytomas

Abstract

A low occurrence rate of spinal cord gliomas (4.3% of primary and glial CNS tumors) and the associated difficulties in building statistically significant cohorts of patients considerably slow down the development of effective approaches to the treatment of spinal cord tumors compared to brain tumors. Despite our extensive knowledge regarding IDH mutations in intracranial tumors, mutations of this gene in spinal cord astrocytomas remain poorly understood. In this study, we report on five cases of identified mutations in the IDH1 gene in spinal cord astrocytoma cells, two of which are unique, as they have never been previously described in CNS gliomas.

Keywords: IDH1; IDH2; NGS; spinal cord astrocytoma.

Fig. 1

Identification of the c.245G> A mutation (p.R82K) in the IDH1 gene by NGS. A diagram of multiple reads of a chromosome 2 fragment involving the IDH1 gene (Integrative Genomics Viewer (IGV)) is shown. The C> T substitution at position 208248538 of chromosome 2, which corresponds to the c.245G> A substitution in the IDH1 gene, is shown in red. The total read depth of this region is 761X; the number of reads of the mutant nucleotide T is 341 (45%)

Fig. 2

Identification of the c.227T> C mutation (p.Ile- 76Thr) in the IDH1 gene by NGS. A diagram of multiple reads of a chromosome 2 fragment involving the IDH1 gene (Integrative Genomics Viewer (IGV)) is shown. The A> G substitution at position 208248556 of chromosome 2, which corresponds to the c.227T> C substitution in the IDH1 gene, is shown. The total read depth of this region is 585X, and the number of reads of the mutant nucleotide G is 317 (54%)