The Science of Albinism

The term “albinism” encompasses a wide range of traits, all of which result from problems with pigment production or distribution. So far, more than 60 different mutations have been isolated from many different species. Many of these mutations and their subsequent effects have been found to be identical in both humans and non-humans.  Since the basic mechanisms for pigment production are nearly identical across all mammals, most data gathered from one species can easily be applied to other species.

Pigment-melanin- is produced through a series of chemical reactions which are made possible by the action of various enzymes in the body. The same general process occurs in all mammals, both human and non-human.  For all mammals the most important enzyme in the production of melanin is tyrosinase. The enzyme tyrosinase encoded by the gene Tyr  is usually referred to in veterinary medicine as C.

The “classic” type of albinism is known as OCA1, Oculocutaneous Albinism, type 1.  OCA1 involves a mutation in the gene which produces tyrosinase . Albinism always effects vision. Dobermans of the four accepted colors do not have these vision problems.  The vision problems in albinism result from abnormal development of the retina (due to lack of normal levels of pigment during development) and abnormal patterns of nerve connections between the eye and the brain. The optic nerves are misrouted to the brain. The CERF examination, commonly used to detect congenital ocular defects in dogs will not detect several of the visual problems associated with albinism. CERF does detect cataracts, progressive retinal atrophy, or persistent pupillary membranes, it does not detect near-sightedness, far –sightedness, astigmatism,loss of depth-perception and the optic nerve abnormalities common to albinos. Since pupillary dilation makes all dogs photosensitive, this means that CERF examinations will not detect photosensitivity either.  Obviously, visual deficits would be a serious handicap for a working breed dog.  Also, the poor vision suffered by albinos may be a partial explanation for the aggressive and /or fearful behaviors often reported in albino Dobermans.  There have been multiple reports of photosensitive/photophobia from owners of albinistic Dobermans, as well as repots of extreme nearsightedness (such as an inability to recognize family members from across a room and inability to chase a ball) and severe lack of depth perception (such as difficulty climbing stairs or with problems falling off of a porch ).  Photophobia  in these dogs was also confirmed by ophthalmogic exam.

More than 50 Tyr mutations have been identified in humans.  They are in general divided into two subtypes, Type 1A having no tyrosinase activity whatever, and no melanin pigmentation, while type 1B(OCA1B) has greatly reduced tyrosinase activity, but with some melanization.   Classical albinos or “complete” albinos are tyrosinase negative and “partial” albinos are tyrosinase positive. Partial albinos ARE still albinos.

The albinistic syndrome may accompany a wide range of health problems.  Some types of albinism affect the immune system, liver, or clotting ability ( eg Hermansky Pudlak Syndrome- abnormal platelets that lead to mild bleeding), and others may cause other physiological abnormalities such as defects in the kidneys or thymus, inner ear defects and neurological abnormalities just to name a few.  Albinism in general predisposes animals to skin cancer as well as photosensitivity/photophobia. Albinisim is a deleterious mutation which effects the whole body.

CONCLUSIONS:

All current evidence supports the conclusion that “white” Dobermans are indeed suffering from some type of albinism. Like other “tyrosinase-positive or “partial “ albinos, they have unpigmented skin and eyes.  Like other albinos, the trait is inherited as a simple recessive trait.  Like several other types of alblinism, they appear to have abnormal melanosomes.  In fact, nationally recognized geneticists agree that these dogs are albino.  Several experts in genetics, alblinism,  pathology, and opthamology have agreed these dogs appear to be albinos, including G.A. Padgett,  D.F. Patterson,

M.F.C. Ladd, W.S. Oetting,  J.P. Scott, and David Prieur. Not a single expert in any of these fields has reached any other conclusion.

SCIENTIFIC CITATIONS:

For example, Dr. Oetting has stated “It sounds as if the dogs do indeed have albinism…These dogs sound like they have OCA1 resulting from mutations of the tyrosinase gene, a major gene in pigment formation”.

G.A. Padgett, DVM, Professor of Pathology, has stated “I would agree with Dr Patterson’s suggestions (1982) that this is probably a mutation in the C series.  I believe it is an albino, although  not the classical pink-eyed tyrosine negative animal which we associate with this term.  They are phototypic, and I believe there is little disagreement with this statement”. After examination of hairs , Dr Padgett says “ The white Doberman is not a normal white.”.  Dr. Padgett also lists albino Dobermans as partial albinos in his book Control of Canine Genetic Diseases.

David J Prieur,DVM, PhD. Of the WSU Dept. of Veterinary Microbiology and Pathology, has stated “Several years ago I expressed my concern regarding the breeding of “white” Doberman Pinscher dogs.  I expressed the opinion that the gene for the white coat was a deleterious gene and that the Doberman Pinscher breed would be better served by not incorporating this gene into the gene pool of the breed.  Although these ‘white’ Dobermans have been shown not to be true albinos, they are tyrosine- positive albinoids with a severe reduction of melanin in oculocutaneous structures.  There have been numerous defects described in animals of other species with genes of this type…I am unaware of any information, published or presented, since I originally expressed my concerns, which would lead me to believe that this gene is not deleterious.”

Dr. M.F.C. Ladd, a British veterinary geneticist, has stated “Albinism means the complete absence of melanin pigment (Searle,1981) .  If one accepts this view, then dogs such as the white Dobermanns with blue eyes , can be termed albinos….Unless much more evidence is forth coming, I feel that the white Dobermann should be looked upon as abnormality, known to exist and hoped to be avoided.

J.P. Scott, PhD., a geneticist at Bowling Green State University, has stated; “Photophobia would constitute somewhat of a handicap to a working dog”, and  “Something must be done” .  I realize that most breeders are  responsible, selecting strains that seem good.  But once an undesirable trait enters a breed, it is not an easy thing to eliminate.

  

RECOMMENDATION:

The Albino Dobermans are not acceptable for they possess a deleterious gene that  causes ocular changes as well as affecting the immune system,  and possessing neurological disorders.  Albinism predisposes the animal to skin cancer as well as photosensitivity/photophobia.  The mission of the parent club is to protect the integrity, health and function  of the breed and not to promote the breeding of unacceptable specimens.

The AKC should honor this and help protect the breed by limiting the albino and factored dogs with a mandatory limited registration.

 

HISTORICAL FACTS:

On November 10, two back and rust parents produced 11 black and rust puppies   and one female mutant albino with translucent blue eyes, pink nose, eye rims and pads.  Padula’s Queen Sheba. All albinos are descendents from this dog.

Registration was sent into AKC with albino written in the color section.The Blue slip was returned explaining that albino is not a color. Photgr
aphs were requested and the registration review committee said the female was white. The first albino was registered without  parent club consultation.  Approximately 6500 descendants have been registered over the past 24 years, roughly 5000 or so are carriers of the albinistic trait.

DPCA asked the AKC to investigate the albino. AKC determined they are purebred.

AKC approved DPCA amendment to our standard: Disqualifying fault: Dogs not an allowed color.

DPCA bought two albino bitches for breeding studies.  These dogs and their Offspring showed:  Photosensitivity, hyperactive fear biters, and prone to solar skin damage.

AKC agreed to provide specialized tracking for albino and albino-factored Dobermans through special registration numbers thus creating the “z” list.

All descendants of Shebah’s parents born since 1996 have carried registration numbers starting with “wz”.

The American Kennel Club

260 Madison Avenue

New York, NY 10010-1609

Mr. David C. Merriam

Chairman of The Board

Mr. James P. Crowley

Executive Secretary

 

 

Dear Sirs,

As the representative of the Doberman Pinscher Club of America I am writing you to let you know our concerns and desires for the handling of the white albino Doberman situation.  The mission of the DPCA is to protect the integrity, purity , health and function of the breed.

First of all we appreciate the effort of the AKC in setting up a tracking system for the albino dogs as well as the carriers of the albinoid gene.  Unfortunately this is only half the battle in the survival of the integrity of our breed.  The only way we can cleanse the breed from this deleterious mutation gene is to not allow these animals to be bred.  By implementing both the tracking system and a restricted registration, only then, can the breed maintain its purity.  The elimination of this gene with its associated detrimental health problems would help maintain the integrity of our breed.

We would be happy to meet with you or the Board for further discussions at the AKC to answer any questions you might have.  Thank you for your consideration.

Sincerely yours,

May S Jacobson, Ph.D.

Associate in Medicine

Children’s Hospital Boston

Harvard Medical School