Unverricht-Lundborg Disease (ULD), also known as progressive myoclonic epilepsy type 1 (EPM1), is a rare genetic disorder characterized by recurrent seizures and progressive neurological deterioration. It is classified as a type of progressive myoclonus epilepsy, which refers to a group of disorders characterized by myoclonus (involuntary muscle jerks) and seizures.
ICD-10 Code: G40.3
ICD-9 Code: 333.0
ULD is caused by mutations in the cystatin B gene (CSTB) located on chromosome 21. This gene provides instructions for producing a protein called cystatin B, which plays a role in regulating the activity of enzymes involved in cellular processes. Mutations in the CSTB gene lead to a deficiency of functional cystatin B, resulting in the accumulation of toxic substances in the brain.
The onset of ULD typically occurs between the ages of 6 and 16, although it can manifest at any age. The disease is characterized by myoclonic jerks, which are sudden, brief muscle contractions that can affect various muscle groups. These jerks often occur spontaneously or in response to external stimuli such as noise or touch. Over time, the frequency and severity of myoclonus may increase, leading to significant impairment in motor function.
In addition to myoclonus, individuals with ULD may experience other types of seizures, including generalized tonic-clonic seizures (formerly known as grand mal seizures) and absence seizures. These seizures can further contribute to the progressive neurological decline seen in ULD.
Other neurological symptoms associated with ULD include ataxia (impaired coordination and balance), cognitive decline, and psychiatric disturbances such as anxiety and depression. The disease may also affect speech and language abilities, leading to difficulties in communication.
Diagnosis of ULD is based on clinical evaluation, medical history, and genetic testing. The presence of characteristic symptoms, such as myoclonus and seizures, along with a family history of ULD, can aid in the diagnosis. Genetic testing can confirm the presence of mutations in the CSTB gene.
Management of ULD primarily focuses on controlling seizures and managing symptoms. Antiepileptic medications, such as valproic acid and clonazepam, are commonly prescribed to reduce the frequency and severity of seizures. Physical and occupational therapy may be beneficial in improving motor function and coordination.
Unfortunately, there is currently no cure for ULD. The disease is progressive, and individuals with ULD may experience a decline in neurological function over time. Supportive care, including psychological support and assistance with daily activities, can help improve the quality of life for individuals with ULD and their families.
In summary, Unverricht-Lundborg Disease is a rare genetic disorder characterized by myoclonus, seizures, and progressive neurological decline. It is caused by mutations in the CSTB gene and is classified as a type of progressive myoclonus epilepsy. The ICD-10 code for ULD is G40.3, and the ICD-9 code is 333.0.