Elizabeth, a 40 year-old Caucasian woman, is referred to Genetics Clinic by her ophthalmologist due to a family history of blindness. Elizabeth's vision is normal with the exception of myopia. Elizabeth's deceased father was blind. Her mother has normal vision. Elizabeth has two brothers, both of whom have normal vision. One of these brothers has two children, a son and a daughter. Both of these children have normal vision.
Elizabeth's paternal grandmother developed blindness. This grandmother
had three children, one son and two daughters. All of her children
developed blindness. One of her daughters, Elizabeth's aunt,
also has symptoms of MS. This aunt has two sons, who have recently
lost their vision. One of these sons has two children, a boy
and a girl who are unaffected. Elizabeth's other aunt, through
her paternal grandmother, has a son and a daughter. Both of
these cousins are affected with blindness. The female cousin,
Amy, also has some type of cardiac arrhythmia. Amy, has three
children all of whom are visually impaired. Amy's brother has
two sons who have normal vision.
Given the family history and the clinical features you suspect
Leber Hereditary Optic Neuropathy.