Torsion dystonia type 30. Clinical observation. Case report

A 58-year-old patient with type 30 dystonia (OMIM619291) detected by genome-wide sequencing was described. A variant of rs778751388, not previously described in the literature, has been identified in the heterozygous state in exon 2 of 24 of the VPS16 gene, leading to the amino acid substitution of P.Cys36A4rg. DNA change (HG38)(protein change) – 20:g.2859771T>C ENST00000380445.8:c.106T>C ENSP00000369810.3:p.Cys36Arg. The patient's disease began quite late, in the 4th decade of life, with spastic torticollis. Subsequently, the spread of the pathological process involving the muscles of the neck, the right upper limb, then the right lower limb, myoclonia of the right hand and tremor of the right lower limb was noted. Secondary mitochondrial disorders were revealed in the form of an increase in the level of lactate in the blood before and after loading with carbohydrates. A decrease in the activity of mitochondrial enzymes in peripheral blood lymphocytes was also revealed: succinate dehydrogenase, an enzyme of the mitochondrial respiratory chain complex II; α-glycerophosphate dehydrogenase involved in mitochondrial fat metabolism; glutamate dehydrogenase (amino acid metabolism in mitochondria). The level of lactate dehydrogenase in peripheral blood lymphocytes in the patient was elevated. The identified secondary mitochondrial disorders may be an indication for the appointment of energotropic medicines along with levodopa drugs and dopaminergic receptor agonists. In the presented observation, it can be argued about autosomal dominant inheritance, since the patient has a characteristic clinical picture of the disease and a mutation in the heterozygous state in the VPS16 gene was detected.