seizures- ?genetic defect

Question
Today I went to check on my fancy mouse Harry.  At first, I thought he slipt through his cage bars.  Then when I lifted his dome and dug a little in his bedding I found him all cold and hidden.  At first I thought he was dead, but then I remembered that my other mouse (Snowy) was cold and stiff shortly after death (30 min- 1 hour.)  Then I saw his eyelids open a bit, I knew I wasn't imagining this when I stretched out my hand with him on it and I saw his chest move up and down.  I tried to keep him warm by holding him in my hands (which were unusually warm) and blowing warm air on him.  I then examined him.  He had
-half open eyes
-flat belly
-something hard in his belly
-no energy
I then checked him for mites but there would have to be a lot of them to cause this, but I still checked; found nothing.
I then took him up to my room there I continued to try to keep him warm.  It didn't work out too well.  But he started to move the upper part of his body.  He opened his eyes wide open (just like normal)  When he did this I opened him a sunflower seed and tried to feed him.  He had it in his mouth, appeared to be eating it but when I looked it was hardly touched.  Then he tried again, it looked like he was getting some progress.  This is where it gets scary.  He started to sit normally while eating, (but he didn't use his hands)but all of a sudden he used his head to shove the food away and he started shaking soooo violently his movements were blurry.  He tried to jump out of my hands (succeeded twice but good thing I was on my bed because that's where he safely landed.)  He bit me a few times so I had to put him back in his cage.  There he laid down.  When I went to check up on him He was all jumpy (reminds me of the flea stage)  Whoa, could this be mouse alzheimer's?!  I made him a nest, put him in it, (well a little away from it then he crawled in.)  put PLENTY of food all around him so that if he had the urge to eat, food was always nearby.  I did that some 10 minutes ago but haven't checked on him since.

Is this deadly?

I cannot go to a vet.  (And I regret it deeply)

He was soo healthy 2 days ago, WHAT HAPPENED?!

PS: No one fed him when I was away for a day and night.

I am SOOOOOO SO SO SO SO SO SOO worried.

Since he is a father-to-be will this affect his offspring? I.O.W. is it genetic?  (he doesn't live in the same cage or actually not even in the same room)

PLS HELP ASAP!

Answer
Dear Jenn,

How terrible!  I'm so sorry.  Harry seems to be having serious seizures of some sort.  There's nothing you can do about this except make him comfortable.  This is so sad.

Unfortunately,  unless Harry had a fall that you don't know about and got a brain injury, it is almost certainly a genetic problem.  This means his offspring COULD have it but they could also just be carriers and be perfectly fine.

The way this works (miniature genetics lesson- I know you know some of this already, bear with me) is that usually a genetic defect is recessive, which means the mouse only has it if he got the gene from both parents:  Although his parents did not have the problem, they were both carriers.  They would probably have been siblings or close relatives for this to be true.  However, even though he has two of the bad gene, he can only give one to each baby, so as long as Ginny doesn't have the same bad gene-- and she shouldn't, being totally unrelated to him-- since the gene is recessive, the babies wouldn't have the problem.  In either case, though, you would neither want to breed Harry again, nor his kids.  Exactly what you were afraid of.  I'm so sorry.

I wish Harry the very best, and the babies the best of health.

By the way, do you have a Petco near you?  My Petco here in NYC takes donated pets and adopts them out to people for free.  If you tame the babies well, your local Petco or even another store may take them off your hands.  Make a few calls before making a decision about their lives, if you haven't done so already.

squeaks of condolence,

Natasha