Cancel G, Stevanin G, Dürr A, Chneiweiss H, Penet C, Pothin Y, Agid Y, Brice A
INSERM U289, Hôpital de la Salpêtrière, Paris, France.
Am J Med Genet. 1995 Oct 9;60(5):382-5. doi: 10.1002/ajmg.1320600507.
Autosomal dominant cerebellar ataxias (ADCA) of type I, a group of clinically heterogeneous neurodegenerative disorders, are known to be genetically heterogeneous since a second locus for ADCA type I (SCA2) has been identified on the long arm of chromosome 12. Linkage analysis was performed in 7 French ADCA type I families in order to estimate its frequency. We analysed 121 individuals, 39 of whom were affected. In 6 families, the SCA2 candidate interval, spanning 12.8 cM, was excluded by bi- and multipoint analysis. In one family (SAL-315), however, the maximal positive lod score reached 2.03 at the D12S79 locus. A posterior probability of 94% in favor of linkage to SCA2 was calculated by homogeneity analysis. The clinical profile of this family was similar to that of previously described SCA1 and non-SCA1 families, except that dementia was observed in 2 out of 6 patients. This may be a clinical idiosyncrasy in this family and was insufficient for a genotype-phenotype correlation.
I型常染色体显性遗传性小脑共济失调（ADCA）是一组临床异质性神经退行性疾病，自12号染色体长臂上发现I型ADCA（SCA2）的第二个基因座以来，已知其具有遗传异质性。对7个法国I型ADCA家系进行连锁分析以评估其频率。我们分析了121名个体，其中39人患病。在6个家系中，通过两点和多点分析排除了跨度为12.8厘摩的SCA2候选区间。然而，在一个家系（SAL - 315）中，在D12S79基因座处最大正连锁值达到2.03。通过同质性分析计算出与SCA2连锁的后验概率为94%。该家系的临床特征与先前描述的SCA1和非SCA1家系相似，只是6名患者中有2名出现痴呆。这可能是该家系的临床特性，不足以进行基因型 - 表型相关性分析。
