The mutually exclusive appearance of lightning-like myoclonic jerks triggered by action in SGCE mutation carriers and of continuous chorea of all limbs in TITF-1 mutation carriers phenotypically discriminated both genetic disorders.
In this study, 18 patients with chorea of unknown cause including index patients of three families with autosomal dominantly inherited nonprogressive chorea have been screened for TITF1 mutations by means of denaturating high-pressure liquid chromatography (dHPLC).
TITF-1 gene mutations should be considered in paediatric and adult patients with unexplained (combinations of) chorea, mental retardation, primary hypothyroidism, and chronic lung disease.