Special case to skip function in bash menu

In the bash menu below if the variant that is inputted is in the format NM_004004.3:c.274G>T the below works perfectly. My question is if the variant inputted is NM_004004.3:-c.274G>T or NM_004004.3:+c.274G>T then the code as is will throw an error due to a biological issue. Is it possible to to have variants that have either a -/+ in them skip the additional function and go straight to the nomenclature function? I apologize for any confusion I am not sure how to explain this, but basically if variants with a -/+ in them go to the additional function then they will error. I don't know if there can be a special case coded in or if there is a better way. Thank you :).

 gjb2() {
    printf "\n\n"
    printf "What is the id of the patient getting GJB2 analysis : "; read id
	printf "Please enter the coding variant the following is an example"
	echo " c.274G>T"
	
    printf "variant(s), use a comma between multiple: "; IFS="," read -a variant
	        
        [ -z "$id" ] && printf "\n No ID supplied. Leaving match function." && sleep 2 && return
        [ "$id" = "end" ] && printf "\n Leaving match function." && sleep 2 && return

        for ((i=0; i<${#variant[@]}; i++))
              do printf "NM_004004.5:%s\n" ${variant[$i]} >> c:/Users/cmccabe/Desktop/Python27/out.txt
        done
	add2text ${id}.txt
	additional
} 
nomenclature() {                 
 # run python NameChecker
    printf "\n\n"
	cd 'C:'
    C:/Users/cmccabe/Desktop/Python27/python.exe C:/Users/cmccabe/Desktop/Python27/run_batch_job.py C:/Users/cmccabe/Desktop/Python27/out.txt C:/Users/cmccabe/Desktop/Python27/out_name.txt NameChecker
   check
} 

I can't see a path to the "nomenclature" function, so any advice here is speculative. And, there may be multiple variants the user entered, what is to be done if one, or several, or all of those do have a +/- sign in them?

Anyhow, try parameter expansion to test for sign existence: [ "$variant" == "${variant#*[+-]}" ] && echo equal || echo different