The genetic analysis of Turkish patients with Huntington's disease.
OBJECTIVE
Exploring the (CAG)n expansion within IT 15 gene in Turkish Huntington's disease (HD) patients and its relation to downstream (CCG)n repeat polymorphism to elucidate population specific haplotypic heterogeneity.


METHODS
Twenty-seven patients with clinical diagnosis of HD from 19 families were sampled. The triplet repeats were evaluated by sizing the fluorescent PCR products on an ABI 310 capillary gel electrophoresis unit.


RESULTS
The number of (CAG)n repeat expansions (range: 40-76, mean: 45.6+/-7) were inversely correlated with age of onset (r=-0.81, P<0.0001). The (CCG)n polymorphism in HD chromosomes was confined to (CCG)7 in all patients. In normal chromosomes CAG polymorphism was accumulated at a relatively higher range (mean: 19.3+/-2.9) together with the common occurrence of(CCG)7 and (CCG)10 alleles.


CONCLUSIONS
The distribution range of the CAG and CCG repeat polymorphism in normal chromosomes and strong linkage disequilibrium between HD mutation and (CCG)7 haplotype provided a striking similarity to populations of western European descent.
Ataç
F B
FB
Baskent University, Faculty of Medicine, Department of Basic Science, Ankara, Turkey.
Elibol
B
B
Schaefer
F
F
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000483:Alleles; D004252:DNA Mutational Analysis; D005060:Europe; D005192:Family Health; D005260:Female; D006239:Haplotypes; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D006816:Huntington Disease / Q000175:diagnosis / Q000208:ethnology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D018911:Trinucleotide Repeats; D014421:Turkey