From OMIMMyoclonic epilepsy of Unverricht and Lundborg, also known as progressive myoclonic epilepsy-1A (EPM1A), is an autosomal recessive disorder characterized by onset of neurodegeneration between 6 and 13 years of age. Although it is considered a progressive myoclonic epilepsy, it differs from other forms in that it appears to be progressive only in adolescence, with dramatic worsening of myoclonus and ataxia in the first 6 years after onset. The disease stabilizes in early adulthood, and myoclonus and ataxia may even improve, and there is minimal to no cognitive decline (summary by Ramachandran et al., 2009).
Genetic Heterogeneity of Progressive Myoclonic Epilepsy
Progressive myoclonic epilepsy refers to a clinically and genetically heterogeneous group of neurodegenerative disorders, usually with debilitating symptoms, although severity varies. See also EPM1B (612437), caused by mutation in the PRICKLE1 gene (608500); Lafora disease-1 (EPM2A; 254780), caused by mutation in the EPM2A gene (607566); Lafora disease-2 (EPM2B; 620681), caused by mutation in the NHLRC1 (608072) gene; EPM3 (611726), caused by mutation in the KCTD7 gene (611725); EPM4 (254900), caused by mutation in the SCARB2 gene (602257); EPM6 (614018), caused by mutation in the GOSR2 gene (604027); EPM7 (616187), caused by mutation in the KCNC1 gene (176258); EPM8 (616230), caused by mutation in the CERS1 gene (606919); EPM9 (616540), caused by mutation in the LMNB2 gene (150341); EPM10 (616640), caused by mutation in the PRDM8 gene (616639); EPM11 (618876), caused by mutation in the SEMA6B gene (608873); and EPM12 (619191), caused by mutation in the SLC7A6OS gene (619192).
A form of progressive myoclonic epilepsy, formerly designated EPM5, is included in 607459 with the primary designation of spinocerebellar ataxia with epilepsy (SCAE).
Other disorders characterized by progressive myoclonic epilepsy include the neuronal ceroid lipofuscinoses (see, e.g., CLN1 (256730); sialidosis (256550); MERFF (545000); and DRPLA (125370), among others (reviews by Ramachandran et al., 2009 and de Siqueira, 2010).)
http://www.omim.org/entry/254800 From MedlinePlus GeneticsProgressive myoclonic epilepsy type 1 (also called Unverricht-Lundborg disease or ULD) is a rare inherited form of epilepsy. Early development is normal in affected individuals. Signs and symptoms of the disorder typically begin between 6 and 15 years of age.
People with progressive myoclonic epilepsy type 1 experience episodes of involuntary muscle jerking or twitching (myoclonus) that increase in frequency and severity over time. Episodes of myoclonus may be brought on by physical exertion, stress, light, or other stimuli. Within 5 to 10 years, the myoclonic episodes may become severe enough to interfere with walking and other everyday activities.
Affected individuals also usually have seizures that involve loss of consciousness, muscle rigidity, and convulsions (tonic-clonic or grand mal seizures). Like the myoclonic episodes, these may increase in frequency over several years. However, the seizures may be controlled with treatment. After several years of progression, the frequency of seizures may stabilize or decrease.
Eventually, people with progressive myoclonic epilepsy type 1 may develop problems with balance and coordination (ataxia) and speaking (dysarthria). They may also experience depression. Another feature of this condition is involuntary rhythmic shaking. This shaking is called intentional tremor because it worsens during intentional movements.
People with progressive myoclonic epilepsy type 1 may live into adulthood. Life expectancy depends on the severity of the condition and a person's response to treatment. The severity of the condition can vary, even among members of the same family.
https://medlineplus.gov/genetics/condition/progressive-myoclonic-epilepsy-type-1