A novel heteroplasmic mitochondrial DNA (mtDNA) micro-deletion affecting the cytochrome b gene (MT-CYB) was identified in an Italian female patient with a multisystem disease characterized by sensorineural deafness, cataracts, retinal pigmentary dystrophy, dysphagia, postural and gait instability and myopathy with prominent exercise intolerance. The deletion is 18-base pair long and encompasses nucleotide positions 15649-15666, causing the loss of six amino acids (Ile-Leu-Ala-Met-Ile-Pro) in the protein, but leaving the remaining of the MT-CYB sequence in frame. The defective complex III function was co-transferred with mutant mtDNA in cybrids, thus unequivocally establishing its pathogenic role. Maternal relatives failed to show detectable levels of the deletion in blood and urinary epithelium, suggesting a de-novo mutational event. This is the second report of an in-frame intragenic deletion in MT-CYB, which most likely occurred in early stages of embryonic development, associated with a severe multisystem disorder with prominent exercise intolerance.

A novel in-frame 18-bp microdeletion in MT-CYB causes a multisystem disorder with prominent exercise intolerance

CAROSSA, VALERIA;FERRETTI, LUCA;GANDINI, FRANCESCA;PALA, MARIA;ACHILLI, ALESSANDRO;OLIVIERI, ANNA;TORRONI, ANTONIO;
2014-01-01

Abstract

A novel heteroplasmic mitochondrial DNA (mtDNA) micro-deletion affecting the cytochrome b gene (MT-CYB) was identified in an Italian female patient with a multisystem disease characterized by sensorineural deafness, cataracts, retinal pigmentary dystrophy, dysphagia, postural and gait instability and myopathy with prominent exercise intolerance. The deletion is 18-base pair long and encompasses nucleotide positions 15649-15666, causing the loss of six amino acids (Ile-Leu-Ala-Met-Ile-Pro) in the protein, but leaving the remaining of the MT-CYB sequence in frame. The defective complex III function was co-transferred with mutant mtDNA in cybrids, thus unequivocally establishing its pathogenic role. Maternal relatives failed to show detectable levels of the deletion in blood and urinary epithelium, suggesting a de-novo mutational event. This is the second report of an in-frame intragenic deletion in MT-CYB, which most likely occurred in early stages of embryonic development, associated with a severe multisystem disorder with prominent exercise intolerance.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/783631
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