Referral Requirements

Important Note:

Requires clear diagnostic referral through Neurology or Genetic Services.

Predictive/carrier testing through Genetic Services only.

Contacts:

Genetic Health Service NZ can be contacted on 0800 476 123.

Neurology can be contacted on (09) 307 4949 ext. 25662.

Background Information

Myoclonus-dystonia is a movement disorder characterised by a combination of rapid, brief muscle-contractions (myoclonus) and/or sustained twisting and repetitive movements that result in abnormal postures (dystonia). The myoclonic jerks most often affect the neck, trunk and upper limbs with less common involvement of the legs. Non-motor features like depression and personality disorders also exist. Symptom onset is usually in childhood or early adolescence but ranges from six months to 38 years. Myoclonus-dystonia is inherited in an autosomal dominant manner. Affected individuals usually have a normal active life span. Genetic imprinting is observed in Myoclonus dystonia patients with almost all children who inherit the mutation from their fathers developing symptoms, while only approximately 10% of children who inherit the mutation from their mothers will develop symptoms.

The SGCE gene is a member of a gene family that also included alpha, beta, gamma, and delta sarcoglycans. In muscles, these genes encode transmembrane components of the dystrophin-glycoprotein complex, which links the cytoskeleton to the extracellular matrix. It is speculated that the disease is due to the loss of function of the protein epsilon-sarcoglycan.

Mutations in the SGCE gene, which encodes the protein epsilon-sarcoglycan, are associated with most cases of familial Myoclonus dystonia tested to date. This locus carries the designation DYT11 (7q21).

For more information about the Molecular Genetics service:

Molecular Genetics information page