Dear Dr. Donohue: I saw your item on bowlegs. I have a son with bowlegs. He's had them since he started walking. Tests show it developed from vitamin D-resistant rickets. It seems to have pasrested.
-- MRS. F.H.
You make an excellent point. Bowlegs can signify an underlying problem, like rickets, which results from inadequate vitamin D. The rickets-weakened bone cannot withstand ordinary stresses. The weightbearing leg bones bow.
Now, the problem is that vitamin D deficiency cause is rare in the U.S., so you must pursue other reasons for it. In fact, the kind of rickets you mention, vitamin D resistant, comes about in spite of normal vitamin intake. The problem lies deeper, in a kidney disorder affecting handling of the vitamin. The person's body just does not respond to vitamin D, so important in the way the body handles calcium.
Other illnesses can lead to rickets. Thanks for allowing this opportunity to explore the subject a bit more than I had earlier. The lesson is that you cannot shrug off bowlegs always as something that was just programmed to happen or as a passing toddler trait. Rickets responds to vitamin supplement.
The bowlegs item drew other mail:
Dear Dr. Donohue: In the item on bowlegs, you wrote, "...so the problem may be familial, which is not the same as saying it's genetic." Please explain how something could be familial but not genetic.
-- B.G.
I made an awkward attempt to explain that bowlegs is not a simple inherited disorder, one that can be tracked genetically through generations. I'll try again.
Every part of our body is genetically programmed for good or bad. Some illnesses and anomalies occur in families sporadically, missing a generation or several generations, perhaps. Yet, those illnesses are due to genes, no matter how we say that. Inheritance patterns are so complex that you often must simplify. To do that you use words like familial, or say something runs in the family.
Put another way, yes, there is a gene, but not everyone gets it, since it has no clear generational pattern.
Dear Dr. Donohue: Is there any difference between osteomalacia and osteoporosis? A sister, who lives distant, writes that she has osteomalacia. I just assumed it was like osteoporosis.
-- MS. J.
These are two different bone diseases.
Osteomalacia, which your sister has, results from a vitamin D deficiency. Her bones are soft. Skeletal pain is the hallmark of osteomalacia.
One of the consequences of the bone softening (malacia means softening) that most patients complain of is hip pain, which in turn may lead to a waddling gait. Osteomalacia is, in fact, the adult version of childhood rickets. It also responds to the same vitamin D therapy.
Osteoporosis can best be described as brittle bone disease. The causes are many, but in women you can usually blame their diminished post menopause supply of estrogen. Vitamin D and calcium play a role, but they are not as central as in osteomalacia.
