A novel intronic mutation in the DDP1 gene in a family with X-linked dystonia-deafness syndrome.
BACKGROUND
X-linked dystonia-deafness syndrome (Mohr-Tranebjaerg syndrome) is a rare neurodegenerative disease characterized by hearing loss and dystonia. So far, 7 mutations in the coding region of the DDP1 gene have been described. They consist of frameshift, nonsense, missense mutations or deletions.


OBJECTIVE
To investigate the presence of mutations in the DDP1 gene in a family with dystonia-deafness syndrome.


METHODS
Seven members belonging to 2 generations of a family with 2 affected subjects underwent genetic analysis. Mutational screening in the DDP1 gene was made through DNA direct sequencing.


RESULTS
We found an intronic mutation in the DDP1 gene. It consists of an A-to-C substitution in the position -23 in reference to the first nucleotide of exon 2 (IVS1-23A>C). The mutation was present in 2 affected men and their respective unaffected mothers, whereas it was absent in the healthy men from this family and in 90 healthy controls.


CONCLUSIONS
Intronic mutations in the DDP1 gene can also cause X-linked dystonia-deafness syndrome. In our case, the effect of the mutation could be due to a splicing alteration.
Ezquerra
Mario
M
Movement Disorders Unit, Department of Neurology, Institut Clínic de Malalties del Sistema Nerviós, Hospital Clínic Universitari de Barcelona, Barcelona, Spain.
Campdelacreu
Jaume
J
Muñoz
Esteban
E
Tolosa
Eduardo
E
Martí
María J
MJ
D000328:Adult; D004252:DNA Mutational Analysis / Q000379:methods; D003638:Deafness / Q000235:genetics*; D005192:Family Health; D005260:Female; D040181:Genetic Diseases, X-Linked / Q000235:genetics*; D006801:Humans; D007438:Introns / Q000235:genetics*; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
D026901:Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D012333:RNA, Messenger; C118122:TIMM8A protein, human