Megacolon the dreaded genetic disease...

[lilspaz68]

This is just an informational post on a dreaded genetic disease. Some people may never have heard of it, but the ones who have experienced it will never ever forget it.
Genetic megacolon occurs as a result of faulty cell development in the embryo stage. The nerve cells in the wall of the colon and/or rectum are either missing or are non-functioning in affected animals. These nerves are necessary in order to move stool along and out. In rats, this means that the stool will back up, and they will bloat. This is most likely painful and eventually results in the death of the animal from malnutrition or bacteremia. Though this condition can occur in any rat, it is very often seen in rats with what are called "high-white" markings. The same relationship occurs in a certain type of Waardenburg syndrome in humans where there is either odd-eyes or a white patch of hair or pigment accompanying the digestive involvement. Lethal white foal syndrome in horses occurs in the overo types (white or mostly white) and causes death from megacolon within a few hours or days of birth.

From ratguide.com
Megacolon can be either early or late (delayed) onset.
With early onset megacolon the signs will usually begin to show as soon as the baby begins eating solid food (around 2 weeks) although sometimes it is not apparent there is a problem till they are 3 or 4 weeks old. Some babies will show a distinct failure to thrive even though they are eating well. This occurs due to the lack of proper absorption of nutrients in the damaged digestive tract. Early onset signs such as bloating, diarrhea, and severe constipation typify the quick advancement of the disease. It is recommended to consider euthanasia rather than to let the disease follow its ultimate lethal course.
Late, or delayed, onset megacolon appears to have the same genetic origin as early onset and is seen in the same lines as early onset. It may be a milder form of the disease, but unfortunately it does progress in severity until it becomes lethal. Often the first sign of delayed onset megacolon is shown by the baby rat’s failure to thrive. Gastrointestinal problems may not become apparent until the rat is 2-5 months old. At that time you may see bloating, diarrhea, constipation, or alternating bouts of diarrhea and constipation. Stools passed may be hard, fibrous, foul smelling, dry, oversized, oddly shaped, blunt on the ends, and have blood or mucus in or between them.
Late onset can also be even more delayed, sometimes not becoming symptomatic until the rat has reached a later age of 4-10 months. With no early warning signs of a problem (such as failure to thrive, unusual stools, or chronic diarrhea) the very late onset type may often be too far advanced, by the time the owner notices a problem, to treat.

2 case histories of early onset megacolon

Health Guide: Megacolon Figure 1c
Health Guide: Megacolon Figure 1b

Late onset megacolon

Health Guide: Megacolon Figure 2a

And here is the wonderful article on high-white rat markings and how to determine high white (lots of cute baby pics too as well as comparison marking pictures)

http://www.midwestrats.org/articlehighwhitecont.html

Just remember not to even contemplate breeding those cute odd-eyed blaze rats you may have, as you could be dooming them to a fate just like Lil'Bit's.

http://www.paw-talk.net/forums/f16/t...eed-43986.html

[VanillaRat]

Good post.

[pinkie1205]

Thanks for posting that Lil Spaz!

[Sasami]

Great post. I'll make it a sticky, if you don't mind?

[lilspaz68]

That's wonderful Sasami. thank you.

[rat freak]

Thats very helpful! Thanks for posting!

[laydeerodentzz]

I new what megacolon was, but seeing those piccys! I never new it was that bad! thats great info! thanx!

[mebri123]

wow poor little rats. i get backed up sometimes lol....... I dont think im gonna have that problem cause i have no rats but cool info for you rat lovers..... on that note i think i need an enima...... he he

[tenebrosity]

It's probably been explained, but I can't seem to find it. WHAT relationship is there between colour alleles (high white markings) and a disease that affects the nerves in the rectum or colon?

[lizzybelle2169]

does anyone know if this can happen to mice as well or just rats?

[tenebrosity]

Bump?

[lilspaz68]

Quote: Originally Posted by lizzybelle2169 does anyone know if this can happen to mice as well or just rats?

mice can get this as well They actually have 2 different genes that can cause MC

[lilspaz68]

Quote: Originally Posted by tenebrosity It's probably been explained, but I can't seem to find it. WHAT relationship is there between colour alleles (high white markings) and a disease that affects the nerves in the rectum or colon?

Does this help at all?

White Spotting Gene (aka: American Husky, High White, Aurora)
Anyone choosing to breed any rat that carries the white spotting gene should be familiar with megacolon. Megacolon is a symptom of the white spotting gene forming at a poor time during fetal development. Megacolon (MC) forms during the fetal development of the neural crest. This interference causes the nerves that serve the colon to not develop properly or incompletely. A kitten with MC will or may appear normal until weaning or starting solid foods. The symptoms develop between 3 and 6 weeks (average). Symptoms include bloating and intermittent diarrhea. There is no known treatment that stops it from happening.

Do some research on these as well to see if you get your answer (sorry I am at work )
Genetic aganglionic megacolon in rats is a congenital condition similar to Hirschsprung’s disease (in humans), lethal white foal syndrome (in horses), piebald related megacolon (in mice), and some types of Waardenburg syndrome (in humans).

[lizzybelle2169]

Quote: Originally Posted by lilspaz68 mice can get this as well They actually have 2 different genes that can cause MC

aww. i wonder if thats what happened to my mouse a month or so ago...she was fine for the longest time and then all of a sudden she started getting bigger and we thought maybe we'd mistaken a girl for a boy and she was pregnant, but she just kept swelling and then she got really lethargic and pass in a few hours after she stopped walking around. when she was going, she kept having kind of messy bowel movements and stuff. it was really weird. she was typically a really healthy mouse and the other two that were in the cage with her are fine still.

[Knuxz]

thanks for posting