We studied six Italian patients harbouring multiple mitochondrial DNA (mtDNA) deletions in order to correlate clinical and molecular features. Earlier age at onset (17 vs 36 years), fewer ragged-red fibres (none vs 35%), and lower proportions of deleted mtDNAs (9 vs 33%) were found in one patient with autosomal recessive inheritance as compared to five with dominant transmission. Our findings add to the features associated with multiple deletions of mtDNA.