1.2.3.1.4 Familial hemiplegic migraine, other loci

This patient, a 45-year-old bus driver, reports a sixth lifetime instance of visual disturbance confined entirely to his right eye. Each time, flickering silvery lines spread across that eye gradually over some seven or eight minutes, before roughly a quarter of the visual field on that same side blacks out completely for several minutes; the darkening always follows the flickering rather than appearing on its own. As the vision starts to clear, weakness develops in his right hand, sometimes making it difficult to grip the steering wheel, which is why he has stopped driving during episodes. He mentions that his cousin has documented weakness of one arm occurring with her own headache attacks, which was assessed and confirmed some years ago by a neurologist as an inherited pattern. Given this, genetic testing of CACNA1A, ATP1A2 and SCN1A was arranged, and the laboratory found no mutation across any of the three.