Stock No. 027417 was formerly associated with CHDI Foundation colony Stock No. 370615 [CHDI-81003014].

Huntington's disease (HD) is an autosomally dominant, fatal neurodegenerative disorder characterized by uncontrolled movements, psychiatric disturbances and cognitive impairment. HD is caused by an unstable trinucleotide (polyglutamine) repeat expansion in the huntingtin gene (HTT; HD or Hdh).


The Hdh CAG 105 knock-in allele (Hdh CAG105 KI) replaces mouse Htt exon 1 with the human HTT exon 1 sequence containing a 105 polyglutamine expansion comprised of a pure CAG expansion [(CAG)₁₀₄CAACAG]. The CAG repeat number is subject to germline and somatic instability, and may expand or contract (see note on CAG instability below). Heterozygous mice are viable and fertile. These mice have not been further characterized to date (April 2014), but may be useful in applications exploring the effect of interrupted CAG tracts versus non-interrupted CAG tracts on somatic instability and RNA structure mechanisms in HD pathophysiology.

This Huntington's disease mouse model is available by way of a collaborative effort between CHDI Foundation, Dr. David S. Grass (Xenogen Biosciences [now Taconic Biosciences]), and The Jackson Laboratory.

Expanded CAG sequences in huntingtin exon 1 may be subject to germline or somatic instability, and may expand or contract. When using lines with unstable CAG repeat length, it is strongly recommended the CAG repeat number be quantified in all the experimental animals; all animals in all experimental groups should carry comparable CAG repeat sizes. CAG repeat sizing of HD mice should be done using high-resolution methods as assays based on agarose gel electrophoresis typically do not provide sufficient resolution to accurately measure CAG repeat numbers. If labs do not have access to the appropriate equipment for determining CAG repeat length, CAG repeats can be evaluated on a fee-for-service basis by Laragen, Inc.