Comment: They've known for 30 year it's often a congenital defect.

(See in situ)

In post: .
In reply to comment: What if scientists discover (see in situ)

They've known for 30 year it's often a congenital defect.

It can be produced in animals by creating nutritional deficiencies.

The defect in humans affect the parathyroid gland; control center for hormone production.

Free includes debt-free!