Journal article

A TOPOISOMERASE-II CLEAVAGE SITE IS ASSOCIATED WITH A NOVEL MITOCHONDRIAL-DNA DELETION

RB BLOK, DR THORBURN, GN THOMPSON, HHM DAHL

HUMAN GENETICS | SPRINGER | Published : 1995

Abstract

Mitochondrial myopathies and encephalopathies can be caused by nucleotide substitutions, deletions or duplications of the mitochondrial DNA (mtDNA). In one such disorder, Kearns-Sayre Syndrome (KSS), large-scale heteroplasmic mtDNA deletions are often found. We describe a 14-year-old boy with clinical features of KSS, plus some additional features. Analysis of the entire mitochondrial genome by the polymerase chain reaction and Southern blotting revealed a 7864-bp mtDNA deletion, heteroplasmic in its tissue distribution. DNA sequencing established that the deletion was between nucleotides 6238 and 14,103, and flanked by a 4-bp (TCCT) direct repeat sequence. Deletions between direct repeats h..

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