engleski

Detection of mitochondrial DNA point mutations in Lebert's optical neurophaty (LOHN)

Mitochondrial DNA (mtDNA) is a small circular molecule of 16.5 kB encoding enzymes of the respiratory chain in mitochondria. It is inherited maternally. Point mutations, deletions and insertions of mtDNA may cause various diseases. Leber's hereditary optic neuroretinopathy (LHON) causes bilateral acute or subacute loss of central vision due to optic atrophy. Most common mtDNA point mutations associated with this hereditary disease are G3460A, G11778A and T14484C causing defects of subunits of complex I (NADH-dehydrogenase-ubiquinone reductase) in mitochondria. G11778A causes most unfavourable visual outcome (blindness), while T14484C is associated with a mild clinical course. We present results of a study of Leber's disease in Croatia. 16 adult patients from five families, 10 males and 6 females were tested. Each family has had a member with visual impairment indicating possible diagnosis of Leber's disease. DNA was isolated from peripheral blood lymphocytes and mtDNA point mutations were detected by means of PCR and RFLP. Point mutation G11778A was detected in 5 DNA samples from two families. Four of these 5 were members of the same family, i. e. 2 female cousins and their 2 sons. The fifth case was from another family. None of the three common mtDNK point mutations for the Leber's defect were found in other 11 DNA samples from the other three families. Molecular diagnosis helps recognize Leber's disease as the mtDNK point mutation and contributes to prognosis and treatment.

mitochondrial DNA; point mutation; LOHN

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