[Identification of ATXN3 intermedial allele associated with a disease phenotype in an SCA3 Han Chinese family].
OBJECTIVE
To investigate the clinical manifestation and the mutation characteristics of intermedial allele associated with a disease phenotype of a Machado-Joseph disease (MJD) family.


METHODS
Polymerase chain reaction, capillary electrophoresis, molecular cloning and sequencing were performed to detect the ATXN3 gene in an spinocerebellar ataxia(SCA) family. The fragments of expanded alleles were subcloned into the pGEM-T plasmids and sequenced.


RESULTS
The expanded repeats at the MJD locus were confirmed by molecular technique. The proband had 43 CAG repeats at the MJD locus. He had two sons with 41 and 64 repeats in the expanded allele respectively.


CONCLUSIONS
A 43 CAG repeat allele was unstable upon inter-generational transmission. The change of the CAG repeat was bidirectional. This is the shortest expanded allele associated with a disease phenotype in the MJD gene reported to date. The identification of the MJD family has reduced the amplitude between the normal and expanded allele repeats.
Yu
Jia
J
Department of Neurology, the First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, P.R. China.
Ma
Jian-hua
JH
Zhang
Xiao-ning
XN
Lei
Jing
J
D000328:Adult; D000483:Alleles; D044466:Asian People / Q000208:ethnology* / Q000235:genetics*; D000067699:Ataxin-3; D001483:Base Sequence; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D056426:Genetic Loci / Q000235:genetics; D006801:Humans; D017827:Machado-Joseph Disease / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D010641:Phenotype; D012091:Repetitive Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000235:genetics*
D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; C092341:ATXN3 protein, human; D000067699:Ataxin-3