Progressive external ophthalmoplegia (PEO) is one of a number of major types of mitochondrial disorders. Most sporadic PEO patients have a heteroplasmic large deletion of mitochondrial DNA (mtDNA) in the mitochondria in skeletal muscles. We herein analyzed mtDNA deletions using sub-cloning and Sanger sequencing of PCR products in a 31-year-old Japanese man with multiple symptoms, including PEO, muscle weakness, hearing loss, leukoencephalopathy and hypogonadism. A large number of multiple deletions was detected, as well as four kinds of deletion breakpoints identified in different locations, including m.3347_12322, m.5818_13964, m.5829_13964 and m.5837_13503. © 2014 The Japanese Society of Internal Medicine.