Geniospasm is movement disorder of the mentalis muscle.
Geniospasm | |
---|---|
Other names | Hereditary geniospasm |
![]() | |
Mentalis muscle | |
Specialty | Neurology |
It is a benign genetic disorder linked to chromosome 9q13-q21 [1] where there are episodic involuntary up and down movements of the chin and lower lip. The movements consist of rapid fluttering or trembling at about 8 Hz superimposed onto a once per three seconds movement of higher amplitude and occur symmetrically in the V-shaped muscle. The tongue and buccal floor muscles may also be affected but to a much lesser degree.[ citation needed]
The movements are always present but extreme episodes may be precipitated by stress, concentration or emotion and commence in early childhood.[ citation needed]
The condition is extremely rare and in a study in 1999 only 23 families in the world were known to be affected,[ citation needed] although it may be under-reported. Inheritance is aggressively autosomal dominant. In at least two studies the condition appeared spontaneously in the families.[ citation needed]
The condition responds very well to regular botulinum toxin injections into the mentalis muscle [2] which paralyse the muscle but cause no impairment of facial expression or speech.
Geniospasm is movement disorder of the mentalis muscle.
Geniospasm | |
---|---|
Other names | Hereditary geniospasm |
![]() | |
Mentalis muscle | |
Specialty | Neurology |
It is a benign genetic disorder linked to chromosome 9q13-q21 [1] where there are episodic involuntary up and down movements of the chin and lower lip. The movements consist of rapid fluttering or trembling at about 8 Hz superimposed onto a once per three seconds movement of higher amplitude and occur symmetrically in the V-shaped muscle. The tongue and buccal floor muscles may also be affected but to a much lesser degree.[ citation needed]
The movements are always present but extreme episodes may be precipitated by stress, concentration or emotion and commence in early childhood.[ citation needed]
The condition is extremely rare and in a study in 1999 only 23 families in the world were known to be affected,[ citation needed] although it may be under-reported. Inheritance is aggressively autosomal dominant. In at least two studies the condition appeared spontaneously in the families.[ citation needed]
The condition responds very well to regular botulinum toxin injections into the mentalis muscle [2] which paralyse the muscle but cause no impairment of facial expression or speech.