In addition to myoclonus dystonia, problems associated with a dysfunctional DAP complex include Duchenne muscular dystrophy.Upwards of 65 mutations of the SGCE gene are thought to cause myoclonus dystonia. The majority of the mutations lead to a truncated protein product that results in the loss-of-function of the epsilon sarcoglycan protein. The dysfunctional protein is ultimately recycled by the cell by degradation mediated by the proteasome, resulting in significant shortages of the integral membrane protein in both neurons and muscle fibers. The mutant allele is inherited in a dominant fashion—that is the mutation can be inherited if one parent has that allele. However, genomic imprinting occurs on the mothers allele, so only the fathers allele is expressed. Therefore, inheriting a mutated, paternal allele of the SGCE gene will result in the expression of the dysfunctional epsilon sarcoglycan protein. Offspring will not produce a mutant protein product in 95% of cases where the mother passes on a mutation in the SGCE gene.While SGCE gene mutations are the central cause of myoclonus dystonia, there have been separate cases where individuals and families present symptoms akin to myoclonus dystonia but lack the mutations at this locus. Base-pair deletions of the DYT1 gene, missense mutations in the DRD2 gene, maternal uniparental disomy, and chromosome 18 linkage have all been associated in rare cases myoclonus dystonia where the SGCE gene is unaffected. Treatment
To date, there is no single, universal treatment that has been found to cure myoclonus dystonia.
In contrast, reticular reflex myoclonus occurs spontaneously to stimuli applied to distal limbs. Spinal myoclonus is caused by defects in spinal organization or connections, and peripheral myoclonus has symptoms of rhythmic jerks due to a neuron-the most common being the hemifacial spasm. Dystonia
Dystonia is a response to simultaneous contraction of agonist and antagonist muscles seen as twisting and contorting that affect posture and stance. Other symptoms can include tremors and muscle spasms due to various interactions of muscle, contractions and movement. Dystonia can be either primary or secondary with the latter being more common. Primary dystonia or "pure" dystonia is only physiological in origin. Secondary dystonia has multiple origins that are physiological, pathological or neurological. Myoclonus dystonia
Myoclonus dystonia includes the rapid contractions of myoclonus alongside the abnormal postures classified under dystonia, as well as neurological and psychiatric issues. This disease typically begins during childhood with symptoms of myoclonus and slight dystonia, most commonly cervical dystonia or writers cramp. Dystonia symptoms tend to not get exaggerated over the course of the disease and is rarely the only associated symptom, while the myoclonus symptoms can become more severe. Psychiatric issues are clinically diagnosed with the aforementioned symptoms and include depression, anxiety, personality disorders and addiction. Obsessive-compulsive disorder is associated with myoclonus dystonia as both have been found to have a commonality on chromosome 7 in various studies.Neurological symptoms are relatively common in those with myoclonus dystonia. Any neurological abnormalities will not normally be present in those affected at a young age.