If newly generated coin disappear, will that affect the total supply? When coins are generated they need to go down certain number of blocks to be mature and spendable, if for some reason they disapear, will that reduce the total supply of the currency, since the generation of new coins is the solving of some math and new block has uncovered some coins?

To make my question more clear, I've added this additional explanation: 

What happend is that a month ago I found a block with new coins while mineing (in my case I wasn't mineing bitcoin but I think the concept applies also to other cryptocurrencies). I had problem with my internet connection and after a while I lost connection. When I solved the internet connection problem the newly generated coins that poped up were no longer there. If the coin supply is limited to 21M, then those coins should vanish forever as they were generated from the solving of the math problem that allows the creation of new coins. If that is the case then these coins should be lost forever, otherwise it means that every time a block containing coins is lost then another one is generated to keep the "total supply" 21M.In order to say that the total supply is limited there should be a limited number of blocks containig coins totaling the announced supply, in case of bitcoin 21M.
The way for newly generated coins to "disappear" is if the corresponding block is orphaned, i.e. a different branch of the block chain becomes the longest (in terms of work) which does not contain that block.  The total money supply could be affected slightly in the short term, if the new dominant branch is longer or shorter (in terms of blocks) than the previous one, and thus contains more or fewer block rewards.  It's not affected in the long run, since the money supply limit is in terms of total coins on the dominant branch.

In other words, if the orphaned block was at height 503567, then the new chain will (eventually) contain a different block at height 503567, and this block will have the same reward as the original orphaned block.  So the economy still contains the coins that correspond to the block reward at height 503567, they have just been paid to a different miner.