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Section on Neuroadaptation
and Protein Metabolism

FXS KI Mouse

Fragile X Premutation: Knock in (KI) Mouse Model

The mouse model of the premutation (KI) was developed in the Laboratory of Molecular and Cellular Biology, NIDDK under the direction of K. Usdin, PhD.

KI mice have the following characteristics:

  • 120 CGG•CGG-repeats in the endogenous murine fmr1 gene
  • Intranuclear neuronal inclusions
  • Purkinje cell loss
  • Elevated fmr1 mRNA
  • Deficiency of FMRP in some brain regions (e.g., inferior olive)

Our studies in adult male KI mice examine:

  • behavior
  • dendrite morphology
  • regional rates of cerebral protein synthesis

Preliminary results indicate that KI mice have the following behavioral deficits [1]:

  • Hyperactivity
  • Impaired social interactions
  • Reduced generalized anxiety
  • Deficit in learning/memory


This work is supported, in part, by the Fragile X Research Foundation.


[1] Qin M, Entezam A, Usdin K, Smith CB Hyperactivity and impaired social interaction in fragile X premutation mice. Soc Neurosci 2008, 310.6