| First Author | Kramer PL | Year | 1994 |
| Journal | Am J Hum Genet | Volume | 55 |
| Issue | (Suppl) | Pages | A191 (Abstr.) |
| Mgi Jnum | J:42642 | Mgi Id | MGI:1097393 |
| Citation | Kramer PL, et al. (1994) A gene for nystagmus-associated episodic ataxia maps to chromosome 19p. Am J Hum Genet 55((Suppl)):A191 (Abstr.) |
| abstractText | Full text of Abstract: A gene for nystagmus-associated episodic ataxia maps to chromosome 19p. ((P.L. Kramer1, E. Smith2, R. Carrero-Valenzuela2, D. Root1, D. Browne2, E. Lovrien2, S. Gancher1, J. Nutt1, M. Litt2.)) Departments of 1Neurology and 2Molecular and Medical Genetics, OHSU, Portland Or. Episodic ataxia (EA) is a rare, autosomal dominant disorder, characterized by attacks of generalized ataxia and relatively normal neurological function between attacks. Onset occurs in childhood or adolescence and persists through adulthood. Penetrance is nearly complete. EA is clinically heterogeneous, including at least two distinct entities: (1) episodes of ataxia and dysarthria lasting hours to days, generally with interictal nystagmus (MIM#l08500); (2) episodes of ataxia and dysarthria lasting only minutes, with interictal myokymia (MIM#160120). The EA/nystagmus patients sometimes develop persistent ataxia and cerebellar atrophy. Previously we reported linkage in four EA/myokymia families to a K+ channel gene on chromosome 12p. We excluded this region in a large family with EA/nystagmus. We now report evidence for linkage to chromosome 19p in this and in one other EA/nystagmus family, based on eight microsatellite markers which span approximately 30 cM. The region is flanked distally by D19S209 and proximally by D19S226. All sixmarkers within this region gave positive evidence for linkage; the highest total two-point lod scores occurred with D19S221 (3.98 at theta=0.10) and D19S413 (3.37 at theta=0.05). Interestingly, Joutel et al. (1993) mapped a gene for familial hemiplegic migraine (FHM) to the region around D19S221. Some individuals in these families have ataxia, cerebellar atrophy and interictal nystagmus, but no episodic ataxia. These results demonstrate that the clinical heterogeneity in EA reflects underlying genetic heterogeneity. In addition, they suggest that EA/nystagmus and some FHM may represent different mutations in the same gene locus on chromosome 19p. A. Joutel, et al. Nature Genetics 5:40-45,1993. |
