F. Lanting: "Snow nose and other pigment problems - A condition frequently found in white dogs is a somewhat temporary loss of black pigment from the bulb of the nose, usually in a center strip. It has been blamed on mild frostbite, but I am convinced this is not the cause. I suspect that this so-called snow nose may be a hormone-related reaction to sunlight, similar to the way length of days affects a female's estrus cycle. But it is something that only happens in dogs that are genetically predisposed to vitiligo (lack of pigmentation). I have seen it mostly in lighter-colored dogs, dogs with liver genes whether heterozygous or homozygous, in white Shepherds, and in other breeds. It has even been reported linked to allergic reaction to certain plastic food dishes. Dogs will frequently develop vitiligo in skin or hair where they have been bitten, burned, vaccinated, or otherwise traumatized. In these instances, the ability of the dermal tissue to multiply melanocytes that produce melanin pigment has been compromised." 

"Gene Connected To A Chronic Skin Condition And Other Autoimmune Diseases Identified

ScienceDaily (Mar. 23, 2007) — Scientists have discovered a connection between a gene and the chronic skin condition vitiligo, as well as a possible link to an array of other autoimmune diseases.
 

Researchers at the University of Colorado at Denver and Health Sciences Center and the Barbara Davis Center for Childhood Diabetes along with St. George’s, University of London worked on this study, that appeared in the March 22 edition of The New England Journal of Medicine.

The researchers began with a study of vitiligo, a condition causing loss of pigment resulting in irregular pale patches of skin, which is visibly detectable in those affected by it. The researchers found that persons with vitiligo also have a risk of developing other autoimmune diseases, as do their close relatives, even those without vitiligo. By searching the genome, the researchers discovered that NALP1 – a gene that controls part of the immune system that serves to alert the body to viral and bacterial attacks – was a key gene involved in predisposing to vitiligo and all the other autoimmune diseases that tracked through these families.

“What’s really exciting for us is that NALP1 hasn’t been specifically implicated in autoimmune diseases before,” said Richard Spritz, MD, director of the Human Medical Genetics Program at UCDHSC and lead investigator for this study. “Since NALP1 appears to be part of our body’s early-warning system for viral or bacterial attack, this gives us ideas about how to try to discover the environmental triggers of these diseases. This finding may also open up new approaches to treatment, possibly for many different autoimmune diseases.”

As a group of approximately 80 disorders that can involve almost any tissue, organ or system, autoimmune and autoinflammatory diseases affect 15 million to 25 million people in the United States. In women, they rank among the top ten causes of death.

Dr. Spritz and his team hope to soon begin organizing a clinical trial of a new treatment for vitiligo, based on their NALP1 discovery. Spritz foresees research labs using the information from the UCDHSC study to replicate or test the results in patients with other autoimmune diseases to see how broad potential applications might be. His hope is that the gene NALP1 is also found to be involved in autoimmune and autoinflammatory diseases such as Type 1 diabetes, Addison’s disease, thyroid disease and lupus, among others.

“All diseases are complex, the result of different genes and environmental risk factors acting together in concert. But if NALP1 turns out to be one of the major genes involved in numerous autoimmune diseases, and if we can interrupt its negative effects, we may have the chance to treat many different chronic autoimmune disorders like vitiligo, lupus and psoriasis and perhaps eventually eliminate them altogether,” said Dr. Spritz.

This research was supported by grants from the National Institutes of Health and funding from the Vitiligo Society (UK) and the National Vitiligo Foundation (USA). "

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The study analyzed two replicate groups of families enrolled from1996 through 2005. Samples were obtained from a total of 656 Caucasian individuals from 114 extended families with vitiligo and other epidemiologically associated autoimmune and autoinflammatory diseases from the United States and the United Kingdom.