Table 2.

Effects of various mutations in the OR region of PrP^C on hereditary and acquired prion diseases.

Disease Type	PrPs	Number of the OR Sequence	Clinicopathological Features	References
Hereditary prion disease	PG14	14 1	• Spontaneously develop cerebellar neurodegeneration. • Accumulate very slightly but substantially PK-resistant PrPScPG14 in the brain. • No prion infectivity associated with PrPScPG14.	[71,72,73]
	Bo10OR-PrP	10 2	• Spontaneously develop cerebellar neurodegeneration. • Accumulate insoluble and slightly PK-resistant 10OR-PrPSc in their brains. • No prion infectivity associated with 10OR-PrPSc.	[74]
Disease Type	PrPs	Number of the OR Sequence	Susceptibility to Prions	References
Acquired prion disease	PrP∆OR	0 1	• Reduced to BSE prions, but not to RML and 22L scrapie prions.	[70]
	Bo7OR-PrP	7 2	• Increased to BSE prions.	[75]
	Bo10OR-PrP	10 2	• Increased to BSE prions.	[74]
	PrP(TetraH>G)	51 (with 4 histidine residues mutated to glycine residues)	• Reduced to RML prions.	[76]

¹ Normal mouse PrP^C contains 5 repeats of the OR sequence. ² Normal bovine PrP^C contains 6 repeats of the OR sequence.