WHAT IS ...

Neuronal ceroid lipofuscinosis The (CL) are inherited metabolic disorders characterized by the accumulation of lipopigments autofluorescence, especially in neurons, causing degeneration of the same and ocular celula. Associated with a kind of epilepsy, psychomotor retardation, progressive loss of sight and early death.

In most cases, the CL are fatal, since there're no known treatment. Currently, there are genetic screening methods that can show us if a dog is normal, carrier (carrier) or reached, so that we can focus on projections from dogs free puppies that will free CL. From the genetic point of view, dogs can be:

- Normal: Normal individuals will not suffer the disease, nor pass puppies.

- CARRIER: The carrier individuals do not suffer the disease. A carrier should only be increasing with a dog free. That way none of the puppies will not suffer the disease (there would be carriers within range).

- WITH: Individuals with the genetic mutation have and develop the disease, more or less severe. These dogs should be increasing, if necessary, with normal individuals. That way none of Chitos suffer the disease (there would be carriers within range).

See the results of different projections ranked above-said. IMPORTANT: avoid giving the puppies with projections.

A defect in the blood-brain barrier:infected dogs have a hypersensitivity to certain drugs, mainly the active ingredient "Ivermectin". An avoidance of these agents prevent a illness. Through a genetic test can detect this defect.

Glaucoma is increased pressure within the eye (intraocular pressure = IOP). Cells inside the eye produce a clear fluid ("aqueous humor") that maintains the shape of the eye and nourishes the tissues inside the eye. (Note: aqueous humor is NOT the same fluid as tears. Tears bathe the outside surface of the eye. Aqueous humor circulates inside the eye. These two fluids do not interact). The aqueous humor drains out of the eye into the bloodstream through the drainage angle–a sieve or meshwork-like area through which aqueous percolates out of the eye. The balance of aqueous fluid production ("the faucet") and drainage ("the drain in the sink") is responsible for maintaining normal pressure inside the eye. In glaucoma, the drain becomes partially or completely clogged but the "faucet" steadily keeps producing aqueous, causing pressure to build inside the eye. If untreated, this increased pressure usually causes irreversible blindness, in addition to stretching and enlargement of the eye.

If breeders of note glaucoma free or glaucoma to parents is free, this means that the dogs at the time the disease was not detected and show no symptoms.

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Merle is actually a heterozygote of an incompletely dominant gene. If two such dogs are mated, on the average one quarter of the puppies will be "double merles" and a high percentage of these double merle puppies could have eye defects and/or be deaf. Knowledgeable breeders who want to produce merle puppies mate a merle with a non-merle dog; roughly half the puppies will be merles without the risk of vision or hearing defects associated with double merle dogs.

In January 2006 scientists at Texas A&M University announced the discovery of a mobile genetic unit called a retrotransposon, responsible for the merle mutation in dogs.

A phantom merle or cryptic merle is one with such small patches of merle—or none at all—that it appears to be a non-merle. In America, a dog with the phantom merle coloring is described as being "cryptic for merle."

The merle gene is associated with congenital deafness, with merle dogs being more likely than other dogs to be born deaf. Dogs with two copies of the merle gene (homozygous merle) have an even higher chance of being born deaf. The suppression of pigment cells (melanocytes) in the iris and in the stria vascularis of the cochlea (inner ear) leads to blue eyes and deafness, respectively. An auditory-pigmentation disorder in humans, Waardenberg syndrome, reflects some of the problems associated with heterozygous and homozygous merle dogs and genetic research in dogs has been undertaken with the goal of better understanding the genetic basis of this human condition.

Dogs who are homozygous for the merle pattern gene often have visual and auditory deficits. These dogs are sometimes referred to as 'double merle' and sometimes incorrectly referred to as 'lethal white.' Ocular defects include micropthalmia, conditions causing increased ocular pressure, and colobomas, among others. Double merle dogs may be deaf or blind or both, and can carry ocular defects in blue or colored eyes.

Deaf, blind, and deaf and blind dogs can have good lives when properly cared for. There are a variety of internet groups dedicated to supporting carers of such dogs. Deaf dogs can compete successfully in agility and there are many anecdotal reports of deaf/blind dogs earning their Canine Good Citizen certification, working as therapy dogs, and competing in dog sports like tracking or Nosework.