Premium
High penetrance and pronounced variation in expressivity of GCH1 mutations in five families with dopa‐responsive dystonia
Author(s) -
Steinberger D.,
Weber Y.,
Korinthenberg R.,
Deuschl G.,
Benecke R.,
Martinius J.,
Müller U.
Publication year - 1998
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410430512
Subject(s) - penetrance , dystonia , expressivity , genetics , exon , mutation , rna splicing , intron , transition (genetics) , biology , gtp cyclohydrolase i , phenotype , gene , endocrinology , neuroscience , rna , nitric oxide synthase , nitric oxide , tetrahydrobiopterin
We performed a clinical and molecular genetic analysis in members of five families with dopa‐responsive dystonia. Four mutations were detected in the gene GCH1 that codes for GTP cyclohydrolase I. Two of these mutations, a delG309 in exon I and a C544T transition in exon 5, have not been described before. They result in inactivation of the enzyme by truncation. The remaining two mutations, both A to G transitions, a(−2)g in intron I and a(−2)g in intron 2, cause truncation by abnormal splicing. The genotype of family members was correlated to their clinical phenotype (obtained before molecular analysis). Clinical symptoms observed in the families included generalized and focal dystonia, abnormal gait, and subtle signs such as an abnormal writing test. High penetrance (0.8–1.0) was observed in four of five families if minor symptoms and signs were considered. A given mutation was more likely to cause symptoms in females than in males, thus confirming the well‐established higher incidence of dopa‐responsive dystonia in females than in males.