In the general cat population, pure white cats are fairly rare, as they require a gene that hides every other possible coat color and pattern in a cat’s genetic makeup. These kinds of cats can have long or short coats and be a single breed or a mix. Sometimes, they do have light-colored eyes. Blue eyes in cats are usually caused by a lack of pigment; the kittens are born with blue eyes and that’s because cats do not get to develop eye pigmentation until the production of melanin around six weeks old.
Just like some human babies, all kittens are born with blue eyes which usually changes color later on. The hue begins to change to the kitten’s true eye color at around 6 or 7 weeks of age. The iris’ melanocytes, the pigment that gives the cat’s eye its adult coloration, develop as soon as the eye is sufficiently mature.
When it comes to white cats with blue eyes, the story is a bit different. About 60 percent of white-dominant kitties got their coloring from mutations in a gene called KIT. In these cats, the blue eyes are seen as a result of a cellular issue: these irises have fewer melanocytes, which are cells that make pigment.
These same cells create skin pigment and play a role in inner-ear functioning. As a result, cats with fewer melanocytes (white cats with blue eyes) may not have enough of the cells for their hearing to function properly, says The Veterinarian, Dr. Lyons. White cats have a genetic makeup that is absolutely similar to that of albino humans, who lack pigment; and this invariably gives them some vulnerabilities, like sensitivity to UV light.
Genetic Makeup Of White Cat With Blue Eyes Breed
Even though few studies have been done to link this to genes known to be involved in human Waardenburg syndrome, which is a syndrome of hearing loss and depigmentation caused by a genetic disruption to neural crest cell development, such a disruption would lead to this presentation in cats as well. Waardenburg syndrome type 2A (caused by a mutation in MITF) has been observed in many pets and small mammals such as dogs, minks, and mice; at least patchy white depigmentation and some degeneration of the cochlea and saccule, as in deaf white cats, has been found.
A dominant masking gene, which is an allele of KIT which suppresses pigmentation and hearing is a major gene that causes a cat to have a white coat. The cat would have an underlying coat color and pattern, but when the dominant white gene is present, that pattern will not be expressed, and the cat will be deaf. A cat that is homozygous (WW) or heterozygous (Ww) for this gene will normally have a white coat despite the underlying pattern. A cat that lacks this dominant masking gene (ww) will exhibit a coat color. KIT mutations also cause patchy depigmentation and different colored irises in humans, and KIT has been found to increase MITF expression, the gene involved in human Waardenburg syndrome type 2A.
A white cat can actually have blue eyes for other reasons that are different from masking. If the underlying coat pattern is one of a pointed cat, the blue eyes may come from the genetics of the pointed gene.
Breeds of White Cat With Blue Eyes
Cat breeds with blue eyes include the Persian, Balinese, Himalayan, Siamese, Birman, and Javanese. Ragdolls are known for sparkling blue eyes, but not all Ragdolls have this color.
#1. Persian Cats
Persian cats are characterized by their soft and silky coats, distinctive smushed faces, and sweet personalities; they are one of the most popular and recognizable cat breeds in the world. White Persians can have blue eyes but, unfortunately, this genetic combination can sometimes be associated with deafness too.
People know Persians to be highly undemanding, loving, and calm. They often like nothing better than snuggling up in their owner’s lap for some affection. This breed isn’t famed for its intelligence, and they’re not going to be as trainable as the Pointed breeds on this list.
#2. White Siaseme
Siamese kittens are usually born with white coat color. In the first days of their life, they may look all white and pink, but then they start developing dark ear edges and nose tips after that. They usually fully develop their point color as they get older. The neck and the body of the cat are warmer and do not develop any or little pigment at the adult Siamese. Their point colors are found around in cooler areas of their body, such as the face, ears, legs, and tail. The layer of fat in overweight Siamese works as an insulator and the cat can become darker in its body.
The pointed Siamese pattern results from the partial albinism gene (Himalayan gene). The point restricted pattern is bound to an enzyme which, when exposed to temperatures above 37°C, causes the hair root to produce little or no pigment for the growing hair. That explains why the Siamese kittens are born completely white.
#3. Himalayan cats
Himalayan cats are good indoor companions cats. Although they can be very moody at times, they are characterized as sweet-tempering, intelligent, and generally very social. Because of their heritage from the Siamese cats, they tend to be more active than Persians. Himalayan cats are known to be very playful; they love to play fetch, and a scrap of crumpled paper or a kitty toy will keep them entertained for as long as possible. Himalayan cats are devoted and dependent upon their humans for companionship and protection. They usually want to be loved, groomed, and petted. Hence, they crave affection.
#4. Birmans cats
Birmans cats have a medium-sized, rectangular body with a broad face and distinct Roman nose. They have ears that are usually as wide on the base as they are tall and should be set as much on top of the head as on the side. They have round eyes, which are often deep sapphire blue.
The Birman’s fur is medium-long and should have a silky texture. This breed does not possess an undercoat, unlike a Persian or Himalayan, thus are much less prone to matting. They have pointed Coat color, save for the contrasting pure white, symmetrical gloves on each paw that are the trademark of the breed. The white color must be present on all toes. Also, it must stop in front of the articulation or at the transition of toes to metacarpals.
Causes Of Deafness In The Cats
In a study of white cats in 1997, 72% of the cats were found to be totally deaf. The entire organ of Corti in the cochlea was found to have degenerated in the first few weeks after birth. Even at that, during these weeks, no brain stem responses could be evoked by auditory stimuli, suggesting that these animals had never experienced any auditory sensations. It was found that some months after the organ of Corti had degenerated, the spiral ganglion of the cochlea also began to degenerate.
White cats with blue eyes are more likely to be deaf than white cats with gold or green eyes. Deafness is associated only with the dominant white gene, not the white spotting gene, says feline geneticist Leslie A. An estimated 40 percent of white cats with blue eyes are deaf, which is high. In fact, it can be viewed this way: If 40 percent of these cats are deaf, it means that the hearing of the majority, which is the remaining 60 percent, is possible.
A Veterinarian, Dr. Lyons, says cats with mixed color, like one green eye and a blue eye, may likely have a hearing impairment in just one ear, especially on the side of the face with the blue eye. In addition, 60% – 80% of the fully white cats with one or both blue eyes are likely deaf. 60% – 80% of the 5% have orange or green eyes and 20% of them are deaf.
In domestic cats with a white coat, it is common for congenital sensorineural deafness to occur. This condition is caused by a degeneration of the inner ear. Deafness in cats is prevalent in white cats than in those with other coat colors. As reported by ASPCA Complete Guide to Cats, about 17 to 20 percent of white cats with nonblue eyes are deaf; similarly, about 40 percent of mixed-colored eyes (odd-eyed) white cats with one blue eye are deaf; and lastly, 65 to 85 percent of blue-eyed white cats are deaf.
Domesticated cats that possess white coats and blue eyes are often completely deaf. Deafness can occur in white cats with yellow, green, or blue irises, despite the fact that it is most likely in white cats with blue irises. In white cats with mixed-colored eyes, it has been found that deafness is more likely to affect the ear on the blue-eyed side White cats can have blue, gold, green, or copper-colored odd eyes.