Sire		Dam		Offspring
clear		clear		100% clear
clear		carrier		50%  clear + 50% carriers
clear		affected		100% carriers
carrier		clear		50%  clear + 50% carriers
carrier		carrier		25% clear + 25% affected + 50% carriers
carrier		affected		50% carriers + 50% affected
affected		clear		100%  carriers
affected		carrier		50% carriers + 50% affected
affected		affected		100% affected

Clear

Genotype: N / N [ Homozygous normal ]

The dog is noncarrier of the mutant gene.

It is very unlikely that the dog will develop Familial Congenital Methemoglobinemia (MetHg). The dog will never pass the mutation to its offspring, and therefore it can be bred to any other dog.

 

Carrier

Genotype: N / CYB5R3 [ Heterozygous ]

The dog carries one copy of the mutant gene and one copy of the normal gene.

It is very unlikely that the dog will develop Familial Congenital Methemoglobinemia (MetHg) but since it carries the mutant gene, it can pass it on to its offspring with the probability of 50%.

Carriers should only be bred to clear dogs.

Avoid breeding carrier to carrier because 25% of their offspring is expected to be affected (see table above)

 

Affected

Genotype: CYB5R3 / CYB5R3 [ Homozygous mutant ]

 

The dog carries two copies of the mutant gene and therefore it will pass the mutant gene to its entire offspring.

The dog is likely to develop Familial Congenital Methemoglobinemia (MetHg) and will pass the mutant gene to its entire offspring