Linkage between late onset, dominant spinocerebellar ataxia and HLA

Clinical study of large kindreds with autosomal dominant HLA-linked spinocerebellar ataxia (SCA1) of late onset

Six families with SCA1 were studied. The clinical data on 35 patients are reported. Cerebellar and pyramidal system involvement was invariably found in association with brainstem, spinal cord and/or peripheral nervous system disorders. In our patients the clinical features appeared concordant when the patients with the same disease duration were compared. Previous reports of SCA1 families had shown great variability in clinical phenotype both interfamilial and intrafamilial. We suggest that the phenotype might appear more homogeneous if disease duration is taken into account.

HLA-linked spinocerebellar ataxia: a clinical and genetic study of large Italian kindreds

Five families with late onset autosomal dominant spinocerebellar ataxia, were studied. Linkage between the disease and HLA loci on the short arm of chromosome 6 was shown in the two largest pedigrees. Clinical study of 26 patients and neuropathological study in one are reported. The disease was characterized by cerebellar and pyramidal involvement variably associated with cranial nerve and peripheral nervous system disorders. A remarkable concordance of the main clinical features was observed in patients with similar disease duration. Comparison with previous reports of HLA-linked spinocerebellar ataxia kindreds showed differences in clinical phenotypes. Although these might be due to genetic variation, the hypothesis is suggested that the phenotype might appear more homogeneous if disease duration is taken into account.

Spinocerebellar ataxia: multipoint linkage analysis of genes associated with the disease locus

Spinocerebellar ataxia (SCA) was studied in a seven-generation (Schut-Swier) kindred using linkage analysis to localize further the autosomal dominant, HLA-linked, disease-producing SCA1 locus relative to four other loci that map to the short arm of human chromosome 6. Genotypes for each locus were determined in as many individuals as possible from a total of 162 affected and unaffected family members that were studied. A maximum pairwise lod score of 8.52 (theta m = 0.10, theta f = 0.22) for linkage between SCA1 and HLA-A was observed. Multipoint linkage analyses for the SCA1, HLA-A, F13A, D6S7, and GLO1 loci revealed that the SCA1 locus is most probably located telomeric to HLA-A, with a likely location between HLA-A and F13A.

Spinocerebellar ataxia (SCA1) in two large Italian kindreds: evidence in favour of a locus position distal to GLO1 and the HLA cluster

Two large Italian pedigrees with HLA-linked spinocerebellar ataxia (SCA1) were typed for HLA-A, -B and -DR as well as for markers either distal (F13A, D6S8) or proximal (D6S29, GLO1) to HLA. Pairwise linkage analyses of SCA1 vs. HLA-A, -B, and -DR showed peak lodscores of 5.3, 5.6 and 3.3 respectively at 7% recombination. Negative lodscores significantly excluded linkage with F13A at less than 5% and with GLO1 at less than 10%. The lodscores with D6S8 and D6S29 had only low peaks. Recombination events in the two pedigrees and the estimated genetic distances of SCA1 from GLO1 and HLA favour the hypothesis of a SCA1 location distal to both of them. An order cen-GLO1-HLA-SCA1-tel appears therefore most likely with present data. These results are discussed in relation to previous reports placing SCA1 distal to HLA in two families and

Spinocerebellar ataxia: variable age of onset and linkage to human leukocyte antigen in a large kindred

We studied a seven-generation kindred with autosomal dominant spinocerebellar ataxia (SCA) to assess linkage relationships to multiple human leukocyte antigen (HLA) loci on the short arm of chromosome 6. Age at onset, clinical features, and course of the disease are described. Although the mean age of onset was 34 years in this family, in 6 of 41 affected individuals onset was below 15 years of age and was accompanied by the unique clinical features of mental retardation and rapid progression of disease. Linkage studies were performed on 93 individuals, and the results show strong evidence for linkage of the SCA locus to the HLA loci. A maximum logarithm of the odds score of 5.83 was found at a recombination fraction of 0.12. This is the first documentation of childhood onset in the HLA-linked form of SCA.

Linkage analysis in spinopontine atrophy: correlation of HLA linkage with phenotypic findings in hereditary ataxia

Because linkage has been reported between HLA and the locus for hereditary ataxia in some families, we studied a 3-generation kindred in which several individuals had dominantly inherited spinopontine atrophy. Affected family members had upper and lower limb ataxia, hypoactive reflexes, loss of proprioception, dysarthria, dysphagia, and pronounced extraocular movement abnormalities. Linkage analysis, based on 25 markers in 28 people, gave strongly negative results with both HLA (z less than -2.0 for theta less than 0.15) and GLO1 (z less than -2.0, theta less than or equal to 0.01). The highest LOD score was for linkage to GPT on chromosome 16 (z = 0.42, theta = 0.0). To assess the relationship between HLA linkage and phenotype, 4 published kindreds with adequate clinical and neuropathological descriptions were used for comparison to the present family. Persons in the 3 families showing evidence for HLA linkage had clinical and pathologic changes consistent with olivopontocerebellar atrophy, type 1. The conditions in the 2 "nonlinked" families were phenotypically distinct from the HLA-linked condition with respect to extraocular movement findings and peripheral sensory nervous system signs. They differed markedly from each other in neuropathologic changes.