Fernandez et al. (2001) reported a 5-generation German family segregating an autosomal dominant syndrome of familial dyskinesia and facial myokymia (FDFM). The disorder was characterized by adventitious movements that sometimes appeared to be choreiform and were associated with ... Fernandez et al. (2001) reported a 5-generation German family segregating an autosomal dominant syndrome of familial dyskinesia and facial myokymia (FDFM). The disorder was characterized by adventitious movements that sometimes appeared to be choreiform and were associated with perioral and periorbital myokymia. The same family had been reported by Bird and Hall (1978) as a possible variant of familial essential chorea (118700) before the recognition of myokymia as a feature. Eighteen members of the family, including 10 males and 8 females, were affected, and all had onset in early childhood or adolescence. The involuntary movements were paroxysmal at early ages, increased in frequency and severity, and in some became constant in the third decade. Thereafter, there was no further deterioration. The adventitious movements were worsened by anxiety but not by voluntary movement, startle, caffeine, or alcohol. The disease was socially disabling, but had no effect on intellect or life span. Chen et al. (2012) provided follow-up of the family reported by Fernandez et al. (2001). The age at onset ranged from 2.5 to 19 years. Reexamination of 1 affected individual at age 50 years showed some improvement of the neurologic manifestations. However, he had developed severe dilated cardiomyopathy at age 46 years, and family history revealed that 4 neurologically affected individuals also developed congestive heart failure. Chen et al. (2012) suggested that heart disease may be a component of FDFM.
In affected members of a large German family with autosomal dominant familial dyskinesia with facial myokymia, Chen et al. (2012) identified a heterozygous mutation in the ADCY5 gene (A726T; 600293.0001). Chen et al. (2012) noted that Adcy5-null mice ... In affected members of a large German family with autosomal dominant familial dyskinesia with facial myokymia, Chen et al. (2012) identified a heterozygous mutation in the ADCY5 gene (A726T; 600293.0001). Chen et al. (2012) noted that Adcy5-null mice develop a movement disorder that is worsened by stress (Kim et al., 2006), supporting the pathogenicity of the A726T mutation.