my $HoA_ref =
 {'GAT' => [2, ['ttt',-3,1],['ttc',-3,3],['ccc',-1,2]],
  'AAA' => [13,['aaa',-1,2],['atg',-2,2]],
  'TTT' => [11,['tta',-2,1],['atc',-3,3]]
 };

# Find key associated with highest value
my ($key, $max);
for(keys(%{$HoA_ref})) {
    if( $HoA_ref->{$_}[0] > $max ) {
        $key = $_;
        $max = $HoA_ref->{$_}[0];
    }
}

# output the item with the max value
print "$key $max:\n";
my @out = @{ $HoA_ref->{$key} };
# skip zeroth element
for(1..$#out) {
    print join ',', @{ $out[$_] }, "\n";
}