How true it is that hemochromatosis is genetic?

Partly true: The disorder is called hereditary hemochromatosis and it is an autosomal recessive disorder. Meaning it is passed from parent to offspring, people can be carriers of the gene, and you have to have 2 copies of the gene to have the disorder: one from the father and one from the mother. Hemochromatosis is an iron overload which can have other causes than hereditary hemochromatosis though.

It is true: The full name is, indeed, hereditary hemochromatosis. The most common form in the western world is mediated by the inheritance of 2 abnormal copies of a gene called hfe. So you need one abnormal copy from mom and one from dad. Single copy carriers do not have hemochromatosis.

Primary is genetic: Primary hemochromatosis is a group of genetic diseases in which iron accumulates excessively in the body. One of these is very common, the rest are uncommon. Secondary hemochromatosis results from iron accumulating in the body as a result of transfusions or very excessive iron ingestion / administration rather than a specific genetic mutation.