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Variation at the MJD locus in the major psychoses
Q Saleem1, M Vijayakumar, M Mutsuddi
1Molecular Biophysics Unit, Indian Institute of Science, Bangalore.
Abstract:
Expansion of triplet repeats has been seen to underlie several disorders that manifest anticipation. Clinical evidence suggests that anticipation occurs in the major psychoses. We studied the distribution of repeat sizes at the Machado-Joseph disease (MJD) locus in a group of patients with the major psychoses. We did not find any large expansions, though 2 patients had alleles that were two repeats larger than in our controls. The difference in allele sizes was larger in the patient sample as compared to the controls. The effect of such large differences might be of functional significance.
Insights
Triplet repeat expansions are linked to anticipation disorders. This study investigated Machado-Joseph disease (MJD) locus repeat sizes in major psychosis patients, finding subtle size differences that may be functionally significant.
Area of Science:
- Genetics
- Neuroscience
- Psychiatry
Background:
- Triplet repeat expansions are known causes of genetic disorders exhibiting anticipation.
- Clinical observations suggest anticipation may also occur in major psychotic disorders.
Purpose of the Study:
- To investigate the distribution of triplet repeat sizes at the Machado-Joseph disease (MJD) locus in patients diagnosed with major psychoses.
- To determine if MJD locus alleles are expanded in individuals with major psychoses.
Main Methods:
- Genomic DNA analysis was performed on a cohort of patients with major psychoses.
- Triplet repeat lengths at the MJD locus were quantified and compared to control samples.
Main Results:
- No large triplet repeat expansions were detected in the patient group.
- Two patients presented alleles that were two repeats larger than the control group's average.
- The variation in allele sizes was greater within the patient sample compared to controls.
Conclusions:
- While large expansions were not found, subtle increases in MJD locus repeat size were observed in some major psychosis patients.
- These minor allele size differences warrant further investigation for potential functional significance in the pathogenesis of major psychoses.