3 siblings & 3 nephews been diagnosed with hemochromatosis i have been tested and have 1 of the 2 genes my ferritin is 420 - shud i be concerned ?

Yes: You need to monitor your ferritin levels to see if you have progressive increase in your iron stores. There is effective treatment through removing blood periodically. If you otherwise qualify, your blood can be used to transfuse someone who needs it. Your local blood bank may provide this service without any cost to you.

Glad you know: Hemochromatosis is very common, several percent of folks, myself included, have one copy of the gene, and it's actually a plus as you absorb dietary iron better than other folks. Get your serum ferritin checked occasionally, and if it starts getting way-high, consider treatment -- or even better, just start donating blood often; it's good for you and good for others.