Kearns Sayre Syndrome: Multiple Ligation-dependent Probe Amplification (MLPA) detection of a large mitochondrial DNA deletion, missed by Long-range PCR.

LIA MAYORGA; SERGIO LAURITO; MRAIANA A. LOOS; HERNÁN D. EIROA; SILVINA DE PINHO; FABIANA LUBIENIECKI; HUGO A. ARROYO; MARÍA ROQUÉ

Innsbruck

Congreso; SSIEM 2014 Annual Symposium; 2014

SSIEM

Background:Mitochondrial diseases are genetic disorders which cause respiratory chain dysfunctions. The complexity of the mitochondrial machinery and its dual genetic origin make them a heterogeneous group of illnesses with a challenging diagnostic approach. Genetic diagnosis starts looking for rearrangements in the 16.5 kb mtDNA. To detect deletions, Long-range PCR has become the most popular method, drawing back the use of Southern Blot. MLPA is used to detect copy number variation in nuclear genes,but its use in mtDNA has not yet been applied widely. Case Report:A Kearns Sayre Syndrome patient with a large mtDNA deletion that was missed by Long-range PCR (because the primers used were located within the deletion) but detected by MLPA, with Southern Blot and Sequencing corroboration. MLPA results were analyzed using 3 internal control probes located in the minor arc for the normalization process,which increased the sensitivity of the method, finding the deletion in muscle and blood. The heteroplasmy level detected by MLPA was comparable to that measured by Southern Blot.Conclusions:By this report, MLPA with an enhanced normalization process, has advantages over other methods like: low cost, easy methodology, primer set does not change outcome, accurate deletion localization, possibility to detect mutations in the same assay.