TY - JOUR
T1 - Haploinsufficiency at the α-synuclein gene underlies phenotypic severity in familial Parkinson's disease
AU - Kobayashi, Hirokazu
AU - Krüger, Rejko
AU - Markopoulou, Katerina
AU - Wszolek, Zbigniew
AU - Chase, Bruce
AU - Taka, Hikaru
AU - Mineki, Reiko
AU - Murayama, Kimie
AU - Riess, Olaf
AU - Mizuno, Yoshikuni
AU - Hattori, Nobutaka
N1 - Funding Information:
We wish to thank Drs Noriko Shindoh and Tsutomu Fujimura for valuable advice and Mei Wang for her generous gift of a-synuclein recombinant proteins. This study was supported in part by: a grant-in-aid for Scientific Research on Priority Areas from the Ministry of Education, Science, Sports, and Culture, Japan; a grant-in-aid for Health Science Promotion; a grant-in-aid for neurodegenerative disorders from the Ministry of Health and Welfare, Japan; a grant-in-aid from the UCR at the University of Nebraska-Omaha; a Centre of Excellence Grant from National Parkinson Foundation, Miami, Florida, USA; and an M. H. Udall NIH PD Centre of Excellence grant.
PY - 2003/1/1
Y1 - 2003/1/1
N2 - To date, two point mutations, G209A and G88C, have been reported in the coding region of the α-synuclein gene in autosomal dominant familial Parkinson's disease. When translated, these lead to the missense mutations Ala53Thr and Ala30Pro, respectively. Reduced mRNA expression of the G209A allele was reported recently in a Greek-American family. Here, we show that α-synuclein mRNA is normally expressed in blood cells and report the results of an analysis of α-synuclein mRNA and protein expression in lymphoblastoid cell lines established from kindreds with the G209A and G88C mutations. mRNA expression was characterized using a TaqMan real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay. We assessed five affected and three unaffected members of a German family with the G88C mutation and two affected members in different, unrelated Greek families with the G209A mutation. The ratio of wild-type to mutant α-synuclein allele expression ranged from 2.2 to 9.2 in the affected individuals with a severe clinical phenotype. The ratios of the expression levels of the wild-type to mutant alleles were only slightly decreased in mild cases and were less than 1.0 in two asymptomatic heterozygotes. Sequence analysis of the RT-PCR products showed only the presence of G in position 88 and G in position 209 in severely affected heterozygotes of the German and Greek families, respectively. High performance liquid chromatography/mass spectrometry demonstrated that, relative to wild-type α-synuclein, there is a reduction of Ala30Pro α-synuclein in lymphoblastoid cell lines originating from severely affected, but not mildly affected G88C/+ heterozygotes. Taken together, these data indicate that there is haploinsufficiency at the α-synuclein gene and that the ratio of expression of the wild-type to mutant alleles correlates with the severity of the clinical phenotype. Furthermore, these findings suggest that haploinsufficiency of α-synuclein mutations may contribute to disease progression in these forms of familial Parkinson's disease.
AB - To date, two point mutations, G209A and G88C, have been reported in the coding region of the α-synuclein gene in autosomal dominant familial Parkinson's disease. When translated, these lead to the missense mutations Ala53Thr and Ala30Pro, respectively. Reduced mRNA expression of the G209A allele was reported recently in a Greek-American family. Here, we show that α-synuclein mRNA is normally expressed in blood cells and report the results of an analysis of α-synuclein mRNA and protein expression in lymphoblastoid cell lines established from kindreds with the G209A and G88C mutations. mRNA expression was characterized using a TaqMan real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay. We assessed five affected and three unaffected members of a German family with the G88C mutation and two affected members in different, unrelated Greek families with the G209A mutation. The ratio of wild-type to mutant α-synuclein allele expression ranged from 2.2 to 9.2 in the affected individuals with a severe clinical phenotype. The ratios of the expression levels of the wild-type to mutant alleles were only slightly decreased in mild cases and were less than 1.0 in two asymptomatic heterozygotes. Sequence analysis of the RT-PCR products showed only the presence of G in position 88 and G in position 209 in severely affected heterozygotes of the German and Greek families, respectively. High performance liquid chromatography/mass spectrometry demonstrated that, relative to wild-type α-synuclein, there is a reduction of Ala30Pro α-synuclein in lymphoblastoid cell lines originating from severely affected, but not mildly affected G88C/+ heterozygotes. Taken together, these data indicate that there is haploinsufficiency at the α-synuclein gene and that the ratio of expression of the wild-type to mutant alleles correlates with the severity of the clinical phenotype. Furthermore, these findings suggest that haploinsufficiency of α-synuclein mutations may contribute to disease progression in these forms of familial Parkinson's disease.
KW - Familial Parkinson's disease
KW - G88C and G209A mutations
KW - Haploinsufficiency
KW - α-synuclein
UR - http://www.scopus.com/inward/record.url?scp=0037228874&partnerID=8YFLogxK
U2 - 10.1093/brain/awg010
DO - 10.1093/brain/awg010
M3 - Article
C2 - 12477695
AN - SCOPUS:0037228874
SN - 0006-8950
VL - 126
SP - 32
EP - 42
JO - Brain
JF - Brain
IS - 1
ER -