Mitochondrial Haplogroups and Age-Related Macular Degeneration

Abstract

Purpose: : To determine if mitochondrial haplogroups H, I, J, T, V, and X are associated with Age-related Macular Degeneration (AMD). Mitochondrial haplogroups are thought to play a role in a number of diseases. Haplogroup J, in particular, has been associated with Leber’s hereditary optic neuropathy and optic neuritis. Haplogroup J may also be related to increased longevity.

Methods: : Total DNA was isolated from the blood samples of 76 AMD subjects and 91 age-matched control subjects. The mean age of these individuals was 79.71 ± 7.58 for AMD patients (range 62-95) and 73.52 ± 9.14 for the controls (range 55-94). Seven segments of mitochondrial DNA containing single nucleotide polymorphisms (SNPs) that identify mitochondrial haplogroups H, I, T, V and X were amplified by polymerase chain reaction and digested with Alu I, Sau96 I, Sau96 I, Nhe I, and Dde I, respectively. Two separate SNPs containing segments of mitochondrial DNA which jointly identify haplogroup J (16126 and 16069) were similarly amplified and digested with HpyCH4V and Afl II, respectively.

Results: : Haplogroup H was the most common haplogroup with a prevalence of 34.21% in the AMD population and 36.76% in the control population. Haplogroup V was the least common haplogroup with 1.33% versus 4.05% in the AMD and normal populations, respectively. Haplogroup J was identified in 7.35% versus 5.49% in the AMD and normal populations, respectively. None of the six haplogroups analyzed were found to be significantly associated with AMD (p>0.05).

Conclusions: : Our study indicates that mitochondrial haplogroups H, I, J, T, V, and X are not associated with AMD. Additional studies on different haplogroups and patient populations will be needed to determine the potential role that mitochondrial haplogroups may play as genetic risk factors for AMD.

Keywords: age-related macular degeneration • mitochondria