Abnormally small eyes at birth, with additional eye defects recognized by eye exam, vision impairment.
Not reported, but presumed normal.
Autosomal recessive with penetrance determined by the maternal genotype (puppies homozygous for disease-associated variant born to a homozygous mother are affected)
Microphthalmos, chorioretinal hypoplasia, and retinal colobomas.
RBP4 and XM_534969.6:c.93_95delGAA
Explanation of Results
| Genotype |
Phenotype |
Interpretation |
| 1-1 (Homozygous Normal) |
Healthy (Normal, Clear) |
1-1 (Homozygous Normal) dogs have two copies of the normal allele and NO COPIES of the disease variant allele that is found in dogs affected with Microphthalmia in the breed. 1-1 dogs will not develop signs of Microphthalmia and NONE of their offspring can inherit the disease variant allele from this dog. 1 = Normal allele; 2 = Disease variant allele. Assistance for making breeding decisions for this disease can be found at https://www.vet.upenn.edu/penngen. |
| 1-2 (Heterozygous) |
Healthy (Carrier) |
1-2 (Heterozygous/Carrier) dogs have one copy of the normal allele and ONE COPY of the disease variant allele that is found in dogs affected with Microphthalmia in the breed. 1-2 dogs will not develop signs of Microphthalmia although each of the offspring has a chance of inheriting the disease variant allele (2). Parents, offspring, breeding partners, and relatives should also be tested. 1 = Normal allele; 2 = Disease variant allele. Assistance for making breeding decisions for this disease can be found at https://www.vet.upenn.edu/penngen. |
| 2-2 (Homozygous Disease Variant) |
Dependent on Genotype of Mother (See Interpretation) |
2-2 (Homozygous Disease Variant) dogs have both (TWO) copies of the disease variant allele that is found in dogs affected with Microphthalmia in the breed. 2-2 dogs will develop signs of Microphthalmia ONLY if their mother also has the 2-2 genotype. If the mother has the 1-1 or 1-2 genotype, this dog will be normal with respect to Microphthalmia. All of the offspring of this dog will inherit a copy of the disease variant allele from this dog. Parents, offspring, breeding partners, and relatives should also be tested. 1 = Normal allele; 2 = Disease variant allele. Assistance for making breeding decisions for this disease can be found at https://www.vet.upenn.edu/penngen. |
Kaukonen M, Woods S, Ahonen S, Lemberg S, Hellman M, Hytönen MK, Permi P, Glaser T, Lohi H. Maternal Inheritance of a Recessive RBP4 Defect in Canine Congenital Eye Disease. Cell Rep. 2018 May 29;23(9):2643-2652. doi: 10.1016/j.celrep.2018.04.118. PMID: 29847795; PMCID: PMC6546432.
