Also being homozygous for LP is associated with CSNB -- Congenital Stationary Night Blindness. All homozygous LPLP horses will lack certain structures in their eye necessary for normal night vision. This defect is present in LPLP horses from birth and may not be discernable by simply observing the horse due to their familiarity/adjustment to the condition. Aside from testing for LP, diagnosis by a veterinary ophthalmologist with electroretinography is the only sure way to confirm or rule out. Heterozygous LPlp horses are not affected.

ERU/equine recurring uveitis, (AKA "moonblindness") is not the same as CSNB-- it is typically adult onset, and is actually a group of immune-mediated diseases of multiple origins that are painful and progressive, can lead to total blindness, and are often linked to leptospirosis. Horses with LP seem to present with it more often than the general equine population, and it tends to progress more seriously in LP_ horses, but this condition is not limited to horses with LP nor believed to be absolutely genetically linked to it at present.

Eye color in LP_ horses is "normal" for whatever other genes the horse has-- ie. LP is not known by itself to cause blue, amber, or greenish eyes.

Appaloosa (capital "A") is a registered bloodline-restricted breed-- one of the older registered breeds in the USA, founded in 1938. The term "appaloosa" or "appy" is sometimes used in the generic for the group of characteristics and patterns associated with LP, just as some people persist in using the term "paint" in the generic to refer the pinto-type patterning. LP and its various patterns and associated characteristics (including CSNB in LPLP individuals, the tendency for sparse/thin mane and tail and etc.), are not restricted to the Appaloosa breed-- there are many breeds worldwide with LP in their genepool, and due to the nature of its inheritance, LP and its traits can also occur in grade and mixed breeds of any kind as long as one parent had an LP gene to pass on (and in the case of patterning, at least one parent had the needed pattern gene(s) ).

LP characteristics are mottled skin visible in thinly haired areas, (it will be mottled pink and black or pink and grey in fully pigmented colors, or mottled pink and salmon in some dilute/double dilute colors) vertically striped (dark and shell) hooves on legs which do not have white markings, white sclera encircling the iris of the eye, (visible "whites" of the eye, AKA "human" eyes) and a gradual increase of white hairs in a more or less distinct pattern/progression over the body with age and season. LP by itself does not cause blanket or leopard patterning-- these patterns are caused by separately inherited genes (only PATN1 is currently testable). LP is however necessary for these patterns to be visible. Horses which are solid without the LP gene can carry pattern genes, and when bred to a mate which has and passes on LP, their pattern gene(s), if passed to their offspring, can then express.

A specific kind of sparse mane and tail are also associated with the LP gene-- not all LP individuals display this trait, and it can be selected for or against to a point, but it is common enough to be trackable and generally observable in any breed/group of horses where LP is present.

NOTE: Terms used to refer to patterns associated with LP for the most part existed before LP-gene and "appaloosa" inheritance was well understood, and as such are mostly phenotype-based and can be somewhat subjective.

"Varnish/varnish roaning", AKA LP-roaning, is a term for the distinct type of roaning caused by the LP gene. If an LP horse lives long enough, it almost always acquires some degree of visible varnish/LP roaning, but amount/rate can vary. It is believed that it is a part/characteristic of LP just as mottled skin etc are, but that there are one or more modifier genes able to control/suppress/enhance its expression, explaining the variation in amount and rate of varnishing/LP-roaning from horse to horse. As varnishing/LP-roaning progresses, it is typical for the bony areas (cheek and nasal bones, poll, shoulder, elbow, hipbone, stifle, knees hocks etc) to retain pigmented hairs-- called "varnish marks", since they resemble the effect of colored varnish being brushed over and staining just the high points of a piece of furniture. Varnishing can occur on a born-solid LP horse, or on the solid areas of an LP horse which also has a white pattern, and it can occur on any base color and in conjunction with any other pattern or white-causing genes.

If an LP horse has the typical round or oval spots associated with LP/pattern, LP-roaning/varnishing will not cause these spots to permanently fade to white. More spots may be revealed as varnish/LP-roaning progresses, and borders on the spots may change, but if spots fade to white and stay that way, something else is affecting them unrelated to LP/PATN-- most often it is grey, or occasionally Rn "classic" roan (although with roan, some dark hairs tend to remain in the spot area seasonally, and spots on legs and head retain most if not all color).

Grey and Rn ("classic") roan are unrelated to the type of roaning associated with the LP gene and are located on different genetic loci-- a horse can have LP and also be grey and/or roan-- expressions of these three different genes can have some phenotypic overlap at some stages, and thus can cause complications with visual differentiation between them.

Typically an LPlp or LPLP foal born without white patterning (not blanket or leopard) is born solid, with or without visible LP characteristics. The first visible characteristic is usually sclera. Mottled skin may be present at birth or may develop later. Hooves are usually pigmented at birth but striping usually begins to develop within the first few weeks. Horses which are LPLP are often (but not always) born with totally or almost totally shell-colored hooves regardless of any pattern or lack of at birth. Development of LP characteristics and/or LP/varnish roaning my take years to express and may progress until the horse dies, or they may stop progressing at any point in time. Onset/rate of progression seems to run in families, to a point.

"Blanket" is a white pattern area with or without spots over a portion of the rear end of the horse-- it can be as small as a white strip over the top of the hips, or as extensive as a full white back half extending from tailhead to withers.

"Snowcap" is a term used to refer to a white blanket -sized pattern with few to no spots in it (long/original term is "snowcap blanket"). Often a with a spotless blanket is LPLP, homozygous for the LP gene. The LPLP "snowcap" blanket can be any size.

"Leopard" is a mostly white horse with colored spots scattered throughout the white. In the "purest sense" of the term, a leopard would be born completely white with its only colored areas being its spots, but in reality most horses referred to as leopards will have some colored areas/mottling/flecking at least in the armpit and groin areas, color around the coronet bands in the absence of non-appaloosa leg markings (these are NOT "varnish marks"-- see above for what those are), and many are born with temporary color on the front of the neck, head, and legs which disappears with the first shed. Horses born with more color than this and/or which retain that color, but which are still mostly white with spots, are called "near leopard".

"Fewspot" is a term used to refer to a white leopard -sized pattern with few to no spots in it (long/original term is "fewspot leopard") . Often a white horse with few to no spots is LPLP, homozygous for the LP gene.

There is phenotypic overlap between what most people would consider a blanket vs. a leopard. The terms "near leopard" (when spotted/LPlp) and "near fewspot" (when nearly spotless/LPLP) are used for these-- foals can be born near leopard/fewspot, or a horse born with a smaller white pattern can LP-roan into these (phenotypic) patterns.

"Halo spots" or "Peacock spots" are spots in an Appaloosa pattern which are ringed by roany or white borders (or sometimes both).

"Moldy" spots are spots which in an LP/spotted non-grey non-Rn roan individual acquire white hairs/specks in them on a cyclical/seasonal basis-- Often a few spots will turn brown, go "moldy" and fade a bit, then return to full color with each change of coat, with different groups of spots in different phases of this cycling.

Foals which have LP_ often are noticeably "adult colored" at birth-- more intense black and red, lacking the more typical buff and silver foal camouflage legs for example. This seems to be more predominant with foals which will be affected early/more rapidly by varnish/LP-roaning.

"Color shifting" is another observed phenomenon in the presence of LP_. In most cases of color shifting, foals are born "normal" or "adult color", but with age, their black pigment "shifts" to a bronze, taupe, or even golden shade. Less commonly, red LP_ horses may shift to a dull or "off" shade.

"Lightning marks" are LP/pattern related white markings on the legs-- they typically originate from the inside and outside tendon grooves along the cannon bones and extend vertically. They may wrap toward the front and back and tend to leave pigmented strips on the front and read of the cannon, and on the front and rear of the knee/hock/fetlock joints-- they can be more extensive and eclipse these areas with white as well but those areas are the last areas to "go". In LPlp individuals there may be spots in the lightning marks. On horses which were born mostly white or which have varnished to mostly white, sometimes the remnants of color on the legs are referred to as lightning marks, but the original/more correct use is for the white markings. Lightning marks are not related to "normal" white leg markings, and will be obscured by white/"cut off" where regular white leg markings occur--- and/or it may be hard to tell where one/the other begins/ends. If a horse has lightning marks in the absence of regular non-LP leg markings, there will be color at the coronet band and hooves will be striped (LPlp) or shell colored (some LPLP horses)-- often with extensive lightning marks or on leopards/fewspots, this "bracelet color" around the coronet will come to a point up the front of the pastern.

White leg and face markings and white spotting caused by other genes-- the W genes, SB1, SW, frame overo, tobiano, and etc-- will never have LP traits, spots, varnishing, etc "within" their white areas-- these white areas are already devoid of pigment and as such are white markings/spots which appear to "cut off/cut through" any color/pattern caused by LP-- LP and its associated spotting/varnishing etc need pigment to express and therefore cannot express in areas already "made white" by other genes. Horses with both LP/pattern type markings and other pinto type spotting together are often referred to as "pintaloosa".

Some of these other white spotting genes, when present with LP/pattern, tend to "boost" expression of white in the LP pattern-- typically making the white area in blankets more extensive and spots smaller and more sparsely scattered for example. Being 'ee' red also tends to "boost" white in LP horses, and being aa/E black tends to suppress white. However these are not all-inclusive observations and are multifaceted-- boosters/suppressors of white/color/patterning, as well as whatever influences the arrangement/size/shape/bordering of spots in LP-related patterns, are acknowledged to be complex and not well understood.

One of these recently observed complexities is the expression of PATN1, the only testable pattern gene in "appaloosa" colored horses at present. The vast majority of horses which are heterozygous or homozygous for PATN1 are leopard or near leopard (when LPlp) or fewspot or near-fewspot (when LPLP). There are however tested PATN1 horses which were born with smaller white patterns, including being born solid. This is not common, but it occurs-- due to the relatively recent availabitliy of the PATN1 test, these more suppressed subjects are typically young horses-- as they mature most tend to "color out" more extensively to resemble a near leopard, but often with a more "roany" rather than white background to their pattern area.

Researchers used to theorize that blanket patterns were the result of a second pattern gene, dubbed "PATN2", but they have dismissed this in favor of a multi-gene model, where the presence/size/position of the blanket is controlled by more than one "smaller" pattern and "pattern helper" genes. Occasionally a horse which would be considered a blanket or snowcapped blanket pattern will test positive for PATN1, but more often they will test n/n for PATN1, meaning their pattern is a result of one/a group o these as-of-yet unidentified/untestable pattern genes.