def replace_del_alt(var):
    """
    Issues occur with deletions hear the ends of the genome.
    Currently - is used to represent an entire string of bases
    being deleted.  Here we replace the ALT with "N" the length
    of REF.
    """
    ref_length = len(var.REF)    
    if var.ALT[0] == '-':
        fixed_alt = 'N' * ref_length
        var.ALT[0] = fixed_alt
        return var
    else:
        return var