Prevalence of Huntington's disease gene CAG trinucleotide repeat alleles in patients with bipolar disorder

• Published in: Bipolar disorders Vol. 17; no. 4; pp. 403 - 408
• Main Authors: Ramos, Eliana Marisa, Gillis, Tammy, Mysore, Jayalakshmi S, Lee, Jong-Min, Alonso, Isabel, Gusella, James F, Smoller, Jordan W, Sklar, Pamela, MacDonald, Marcy E, Perlis, Roy H
• Format: Journal Article
• Language: English
• Published: Denmark Blackwell Publishing Ltd 01.06.2015
• Subjects: Adult; Alleles; Amyotrophic Lateral Sclerosis - genetics; bipolar disorder; Bipolar Disorder - genetics; depression; Depressive Disorder, Major - genetics; Female; Genotype; Humans; Huntingtin Protein; Huntington Disease - diagnosis; Huntington Disease - genetics; Huntington's disease; Male; Middle Aged; Nerve Tissue Proteins - genetics; neurodegenerative disease; Penetrance; polyglutamine expansion; Prevalence; Statistics as Topic; trinucleotide repeat; Trinucleotide Repeats - genetics; bipolar disorder; neurodegenerative disease; depression; trinucleotide repeat; Huntington's disease; polyglutamine expansion
• ISSN: 1398-5647; 1399-5618; 1399-5618
• DOI: 10.1111/bdi.12289

Objectives Huntington's disease is a neurodegenerative disorder characterized by motor, cognitive, and psychiatric symptoms that are caused by huntingtin gene (HTT) CAG trinucleotide repeat alleles of 36 or more units. A greater than expected prevalence of incompletely penetrant HTT CAG repeat alleles observed among individuals diagnosed with major depressive disorder raises the possibility that another mood disorder, bipolar disorder, could likewise be associated with Huntington's disease. Methods We assessed the distribution of HTT CAG repeat alleles in a cohort of individuals with bipolar disorder. HTT CAG allele sizes from 2,229 Caucasian individuals diagnosed with DSM‐IV bipolar disorder were compared to allele sizes in 1,828 control individuals from multiple cohorts. Results We found that HTT CAG repeat alleles > 35 units were observed in only one of 4,458 chromosomes from individuals with bipolar disorder, compared to three of 3,656 chromosomes from control subjects. Conclusions These findings do not support an association between bipolar disorder and Huntington's disease.