Mutations in the cyclic adenosine monophosphate response element of the tyrosine hydroxylase gene
ABSTRACT Tyrosine hydroxylase (TH) deficiency (OMIM 191290) is one cause of early-onset dopa-responsive dystonia. We describe seven cases from five unrelated families with dopa-responsive dystonia and low homovanillic acid in cerebrospinal fluid who were suspected to suffer from TH deficiency. Analysis of part of the TH promotor showed five homozygous and two heterozygous mutations in the highly conserved cyclic adenosine monophosphate response element. Our data suggest that, if no mutations are found in the coding regions of the gene in patients strongly suspected of TH deficiency, the search for pathogenic mutations should be extended to regulatory promotor elements.
- SourceAvailable from: Meng Wang[Show abstract] [Hide abstract]
ABSTRACT: Tyrosine hydroxylase (TH) is the rate-limiting enzyme in catecholamine biosynthesis and its gene proximal promoter (< 1 kb upstream from the transcription start site) is essential for regulating transcription in both the developing and adult nervous systems. Several putative regulatory elements within the TH proximal promoter have been reported, but evolutionary conservation of these elements has not been thoroughly investigated. Since many vertebrate species are used to model development, function and disorders of human catecholaminergic neurons, identifying evolutionarily conserved transcription regulatory mechanisms is a high priority. In this study, we align TH proximal promoter nucleotide sequences from several vertebrate species to identify evolutionarily conserved motifs. This analysis identified three elements (a TATA box, cyclic AMP response element (CRE) and a 5′-GGTGG-3′ site) that constitute the core of an ancient vertebrate TH promoter. Focusing on only eutherian mammals, two regions of high conservation within the proximal promoter were identified: a ∼250 bp region adjacent to the transcription start site and a ∼85 bp region located approximately 350 bp further upstream. Within both regions, conservation of previously reported cis-regulatory motifs and human single nucleotide variants was evaluated. Transcription reporter assays in a TH -expressing cell line demonstrated the functionality of highly conserved motifs in the proximal promoter regions and electromobility shift assays showed that brain-region specific complexes assemble on these motifs. These studies also identified a non-canonical CRE binding (CREB) protein recognition element in the proximal promoter. Together, these studies provide a detailed analysis of evolutionary conservation within the TH promoter and identify potential cis-regulatory motifs that underlie a core set of regulatory mechanisms in mammals.02/2015; 10(1):74-90. DOI:10.1007/s11515-014-1341-z
- [Show abstract] [Hide abstract]
ABSTRACT: Tyrosine hydroxylase (TH) deficiency is a rare autosomal recessive and often treatable neurometabolic disorder with variable phenotypes. More than 20 pathological mutations have been identified in patients with TH deficiency. We report the case of a 10-month-old male patient who presented with developmental delay, hypotonia and oculogyric crises to the Salmaniya Medical Complex in Manama, Bahrain. At a later stage, he developed orofacial dyskinaesia and tremors with hyper-reflexia and clonus. A magnetic resonance imaging scan of the brain showed mild atrophy with widened ventricles and genetic testing revealed a novel homozygous mutation (c.938G>T; p.Arg313Leu) in exon 9 of the TH gene. The patient showed a remarkable response to treatment using combined levodopa-carbidopa. In this case, the orofacial dyskinaesia may be a specific clinical association unique to this novel mutation, which is the first to be described in Bahrain and the Middle East.Sultan Qaboos University medical journal 08/2014; 14(3):e397-400.
- Movement Disorders 07/2011; 26(8):1558-60. DOI:10.1002/mds.23564 · 5.63 Impact Factor