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G Cancel

Publications and source records attributed to G Cancel.

42 records · Page 3Linked to original sources
PubMed1994

The gene for Machado-Joseph disease maps to the same 3-cM interval as the spinal cerebellar ataxia 3 gene on chromosome 14q.

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder in families of Portuguese-Azorean ancestry. The gene responsible for MJD has been assigned to a 29-cM interval on chromosome 14q. A large Brazilian family with MJD was genotyped with six new microsatellite markers spanning 19 cM on chromosome 14q. Linkage analysis and haplotype reconstruction reduced the MJD candidate region to a 3-cM interval between markers D14S280 and D14S81, permitting positional cloning. This interval also contains the spinal cerebellar ataxia 3 (SCA3) gene, responsible for a genetic subtype of the type I autosomal dominant cerebellar ataxias, clinically related to MJD. This result supports the hypothesis that abnormalities in the same gene may be responsible for both disorders. The minor clinical differences between the two diseases may result from allelic heterogeneity.

Cerebellar Ataxia↗
PubMed1994

Clinical and genetic analysis of a Tunisian family with autosomal dominant cerebellar ataxia type 1 linked to the SCA2 locus.

Autosomal dominant cerebellar ataxias (ADCA) type 1 are a clinically and genetically heterogeneous group of neurodegenerative disorders. We report a large Tunisian ADCA type 1 family in which 17 patients (mean age at onset +/- SD = 35.6 +/- 15.3 years) were examined. There was mean anticipation of 10.3 +/- 15.4 years in this family; anticipation was greater in paternal (28 +/- 8.2 years) than in maternal (2.7 +/- 10.9 years) transmission. Linkage analysis performed with microsatellite markers linked to the spinal cerebellar ataxia 1 (SCA1) locus on chromosome 6p and the SCA2 locus on chromosome 12q excluded linkage to SCA1, but there was close linkage with marker D12S105 (Zmax = 2.51 at theta = 0.00). This result was confirmed by multipoint analysis, which generated a maximal lod score of 3.46 at this locus. Multipoint analysis and haplotype reconstruction reduced the interval containing the SCA2 locus to 6.4 cM, a narrowing of the 35-cM interval in a previously described Cuban SCA2 family with a clinical picture similar to that of our family, including a high frequency of postural and action tremor.

Adult↗
PubMed1994

A third locus for autosomal dominant cerebellar ataxia type I maps to chromosome 14q24.3-qter: evidence for the existence of a fourth locus.

The autosomal dominant cerebellar ataxias (ADCA) type I are a group of neurological disorders that are clinically and genetically heterogeneous. Two genes implicated in the disease, SCA1 (spinal cerebellar ataxia 1) and SCA2, are already localized. We have mapped a third locus to chromosome 14q24.3-qter, by linkage analysis in a non-SCA1/non-SCA2 family and have confirmed its existence in a second such family. We suggest designating this new locus "SCA3". Combined analysis of the two families restricted the SCA3 locus to a 15-cM interval between markers D14S67 and D14S81. The gene for Machado-Joseph disease (MJD), a clinically different form of ADCA type I, has been recently assigned to chromosome 14q24.3-q32. Although the SCA3 locus is within the MJD region, linkage analyses cannot yet demonstrate whether they result from mutations of the same gene. Linkage to all three loci (SCA1, SCA2, and SCA3) was excluded in another family, which indicates the existence of a fourth ADCA type I locus.

Adult↗
PubMed1993

Phenotypic variability in autosomal dominant cerebellar ataxia type I is unrelated to genetic heterogeneity.

Families with autosomal dominant cerebellar ataxia (ADCA), a heterogeneous group of diseases, were investigated prior to and during genetic linkage analysis. We report here on the clinical features of 122 affected individuals from 36 unrelated families with ADCA type I, the most common type. Our results indicate an anticipation expressed in a mean 9.4 year earlier age at onset and more rapid clinical progression in successive generations. There was no imprinting, since age at onset, disease duration and severity of the disease were independent of parental transmission. Progressive cerebellar ataxia was variably associated with signs such as ophthalmoplegia, dysphagia, sphincter disturbances, briskness or loss of tendon reflexes, decreased vibration sense and amyotrophy, a variability correlated with disease duration. Linkage analysis of 10 informative families with microsatellite markers, located on the short arm of the chromosome 6, allowed the identification of four families showing positive linkage to the SCA1 (spinal cerebellar ataxia 1) locus and six non-SCA1 families for whom linkage to this locus was excluded. This reflects non-allelic genetic heterogeneity. Thus, the analysis of clinical signs associated with cerebellar ataxia in SCA1 versus non-SCA1 kindreds did not distinguish between the two groups. The clinical picture of ADCA type I did not reflect the genetic heterogeneity of the disease.

Adolescent↗