This is what I've found on google:
Sabino
May well be polygenic and causes
abundant white on the legs, and then
creeps up as belly spots and body
spots that are usually flecked and
roaned. Usually the head is largely
white, as well.
In the minimum expression, sabinos can show as
little as a couple of low stockings and a star; in
the extreme expression, sabinos can be pure
white. These snow-white foals are sometimes
mistaken as being "living lethal whites," but it's
easy to tell the difference: pure-white sabinos
are healthy but lethal white foals will die within
two-three days of being born.
Sabino Overos
Characteristics
1. Usually involves extensive leg white and facial white.
2. Body spots are usually on the belly, and can either occur as roan areas, speckled areas or rarely as white patches with clean, crisp edges. Sabino horses with clean, crisp edges are often confused with frame overo horses.
3. Most have flecked with white or roaned, especially when there is extensive sabino markings.
4. Sabinos with extensive white markings will usually have roan or speckled areas on the ears, tail base, flank and chest areas.
5. A minimal white sabino will have extensive white marks, on the face and sock, but no white body spots. This is often overlooked, and the horses are thought to be solid.
6. May have blue or partially blue eyes.
Genetics
This gene often acts like a single dominant gene. This color pattern has also produced lethal white foals, while some other white foals are still viable and normal. The sabino color pattern may also include several different distinct patterns which have not yet been researched.
Sorry more!!
Overo refers to a pinto coloration pattern of white over dark body markings in horses. There are at least three different genes which fall under the "overo" classification: frame overo, sabino, and splash overo. Overos often have fully blue or partially blue eyes. [1] To complicate matters further, some of the spotting gene patterns can be combined to produce a horse with multiple color traits. The genetics of overo and related patterns are still being researched and are not fully understood. The frame and splash traits may be either polygenic, dominant, or incomplete dominants, although they can be so minimally expressed on an individual that the animal is mistaken for a "solid" colored horse. Unlike tobiano patterning, there is currently no DNA test that can identify an overo gene or gene complex.
Sabino coloring is usually characterized by roaning at the edges of white markings, belly spots, irregular face markings, especially white extending past the eyes or onto the chin, white above the knees or hocks, and "splash" or "lacy" marks anywhere on the body, but particularly on the belly. Many sabinos have patches of roan coloring on part of the body, especially the barrel and flanks. Some sabinos may have a dark foot or two, but most have four white feet. Both blue and brown eyes are seen. A wide variety of irregular color patterns are accepted as Sabino. Sabino genetics are also thought to be the most common cause of solid-colored horses with "chrome," a term referring to horses that have lots of facial white and high leg white, with the occasional belly spot or roan patch.
White stockings that extend past the knee or hock, sometimes combined with a bald face (white extending to or past the eyes) are considered evidence of at least minimal expression of the sabino gene-complex. The most extreme manifestation of sabino is called "sabino white" or "maximum white," which produces a totally white-colored horse (see section below).
And I found this!! It has rabicano in there too which has nothing to do with this thread but it also contains differences between a true roan and a sabino so thought it might be helpful!
Sabino color may at times resemble a roan, or a Rabicano, but it is quite different genetically. Sabino, rabicano, and roan patterns have even been confused by some breed associations, including the Arabian, Thoroughbred, Tennessee Walker, Clydesdale and Shire registries, some of which still use the term "roan" to describe both sabinos and rabicanos.
A true roan is differentiated from a Sabino by the absence of splashy white markings and a head and legs that are darker than the body. Most roans have very little white, in fact. However, again, the sabino gene does sometimes occur in conjunction with a roan-colored coat, producing a horse with both roan and sabino traits. A rabicano is even more distinct, having roan patches confined only to limited parts of the body, with large solid areas.
OH!
