Exhaustive analysis of BH4 and dopamine biosynthesis genes in patients with Dopa-responsive dystonia

Article Article scientifique Article Exhaustive analysis of BH4 and dopamine biosynthesis genes in patients with Dopa-responsive dystonia eng 2009 author Clot Fabienne author Grabli David author Cazeneuve Cecile author Roze Emmanuel author Castelnau Pierre author Chabrol Brigitte author Landrieu Pierre author Nguyen Karine 652549 author Ponsot Gerard author Abada Myriem author Doummar Diane author Damier Philippe author Gil Roger author Thobois Stéphane author Ward Alana J. author Hutchinson Michael author Toutain Annick author Picard Fabienne 123049 author Camuzat Agnes author Fedirko Estelle author San Chankannira author Bouteiller Delphine author LeGuern Eric author Durr Alexandra author Vidailhet Marie author Brice Alexis 1753-1763 10.1093/brain/awp084 19491146 0006-8950 http://brain.oxfordjournals.org/content/132/7/1753.full.pdf Dopa-responsive dystonia is a childhood-onset dystonic disorder, characterized by a dramatic response to low dose of L-Dopa. Dopa-responsive dystonia is mostly caused by autosomal dominant mutations in the GCH1 gene (GTP cyclohydrolase1) and more rarely by autosomal recessive mutations in the TH (tyrosine hydroxylase) or SPR (sepiapterin reductase) genes. In addition, mutations in the PARK2 gene (parkin) which causes autosomal recessive juvenile parkinsonism may present as Dopa-responsive dystonia. In order to evaluate the relative frequency of the mutations in these genes, but also in the genes involved in the biosynthesis and recycling of BH4, and to evaluate the associated clinical spectrum, we have studied a large series of index patients (n = 64) with Dopa-responsive dystonia, in whom dystonia improved by at least 50% after L-Dopa treatment. Fifty seven of these patients were classified as pure Dopa-responsive dystonia and seven as Dopa-responsive dystonia-plus syndromes. All patients were screened for point mutations and large rearrangements in the GCH1 gene, followed by sequencing of the TH and SPR genes, then PTS (pyruvoyl tetrahydropterin synthase), PCBD (pterin-4a-carbinolamine dehydratase), QDPR (dihydropteridin reductase) and PARK2 (parkin) genes. We identified 34 different heterozygous point mutations in 40 patients, and six different large deletions in seven patients in the GCH1 gene. Except for one patient with mental retardation and a large deletion of 2.3 Mb encompassing 10 genes, all patients had stereotyped clinical features, characterized by pure Dopa-responsive dystonia with onset in the lower limbs and an excellent response to low doses of L-Dopa. Dystonia started in the first decade of life in 40 patients (85%) and before the age of 1 year in one patient (2.2%). Three of the 17 negative GCH1 patients had mutations in the TH gene, two in the SPR gene and one in the PARK2 gene. No mutations in the three genes involved in the biosynthesis and recycling of BH4 were identified. The clinical presentations of patients with mutations in TH and SPR genes were strikingly more complex, characterized by mental retardation, oculogyric crises and parkinsonism and they were all classified as Dopa-responsive dystonia-plus syndromes. Patient with mutation in the PARK2 gene had Dopa-responsive dystonia with a good improvement with L-Dopa, similar to Dopa-responsive dystonia secondary to GCH1 mutations. Although the yield of mutations exceeds 80% in pure Dopa-responsive dystonia and Dopa-responsive dystonia-plus syndromes groups, the genes involved are clearly different: GCH1 in the former and TH and SPR in the later. Adolescent Adult Age of Onset Alcohol Oxidoreductases/genetics Biopterin/*analogs & derivatives/biosynthesis Child Child, Preschool Dopamine/*biosynthesis Dopamine Agents/*therapeutic use Dystonic Disorders/drug therapy/*genetics/metabolism Female GTP Cyclohydrolase/genetics Heterozygote Humans Levodopa/*therapeutic use Male Middle Aged Point Mutation Tyrosine 3-Monooxygenase/genetics Ubiquitin-Protein Ligases/genetics Young Adult Dewey 616.8 61 Département des neurosciences cliniques 226 false Brain 132 Pt 7 aaefd706-c12e-44ff-a5df-779e9cfeb6b2 Article Restricted file1.pdf 331740 application/pdf restrictedAccess Faculté de médecine / Section de médecine clinique / Département des neurosciences cliniques

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Exhaustive analysis of BH4 and dopamine biosynthesis genes in patients with Dopa-responsive dystonia	Brain			2009	676	0

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Nguyen, Karine