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 GeneticsUnverricht-Lundborg disease is a rare inherited form of epilepsy. Affected individuals usually begin showing signs and symptoms of the disorder between the ages of 6 and 15.
Unverricht-Lundborg disease is classified as a type of progressive myoclonus epilepsy. People with this disorder 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 involving 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 but may be controlled with treatment. After several years of progression, the frequency of seizures may stabilize or decrease.
Eventually people with Unverricht-Lundborg disease may develop problems with balance and coordination (ataxia), involuntary rhythmic shaking called intention tremor because it worsens during movement, difficulty speaking (dysarthria), depression, and a slow, mild decline in intellectual functioning.
People with Unverricht-Lundborg disease typically live into adulthood. Depending on the severity of the condition and a person's response to treatment, life expectancy may be normal.
https://medlineplus.gov/genetics/condition/unverricht-lundborg-disease