The clinical phenotype of early-onset isolated dystonia caused by recessive COL6A3 mutations (DYT27).

Background and Purpose: We recently identified mutations in the a3 (VI) collagen gene COL6A3 that cause autosomal-recessive isolated dystonia (DYT27). This article gives a detailed description of the clinical phenotype associated with this new type of dystonia. Methods: A total of 5 recessive COL6A3 mutation carriers underwent clinical examinations, and case histories were recorded on videotape. Results: Biallelic COL6A3 mutations cause isolated dystonia with interindividual heterogeneity of distribution and severity. Dystonia was generalized in 3 patients, pronounced in the cranio-cervical region, upper limbs, and trunk; segmental in 1 patient, with the neck and upper limbs affected; and focal with cervical involvement in another patient. Symptoms began in childhood, adolescence, or early adulthood, initially affecting the neck as cervical dystonia or the hand as writer's cramp. Conclusion: COL6A3-associated dystonia represents a newly identified autosomal-recessive entity characterized clinically by an early symptom onset with variable distribution