[Leber hereditary optic neuropathy: Usefulness of next generation sequencing to study mitochondrial mutations on apparent homoplasmy].

BACKGROUND AND OBJECTIVE

Leber hereditary optic neuropathy is characterized by acute and subacute visual loss, produced by mitochondrial DNA mutations.

PATIENTS AND METHODS

The molecular study of a family with only one affected member is presented.

RESULTS

In the index case and in her mother, the mitochondrial mutation m.11778G>A in the MT-ND4 was detected in the heteroplasmic state. The index case's sister, without ocular manifestations, asked for genetic counseling. The study of the mentioned mutation by Sanger sequencing identified it in an apparent homoplasmic state. However, by means of next-generation sequencing (NGS), the mutation was actually in a heteroplasmic state.

CONCLUSIONS

Regarding genetic counseling, verifying a mutation in homoplasmic state is really important. We have observed that NGS allows us to discriminate between high levels of heteroplasmy and homoplasmy, meaning that it is a useful technique for the analysis of apparent homoplasmic results obtained with less sensitive technique, as Sanger sequencing.