Alport syndrome. Report of a case with severe maxillofacial manifestations.

Alport syndrome (AS) represents a genetic cause of renal failure that affects about 1 in 5,000 Americans. In cases of AS, the problem resides on the X chromosome. Specific mutations to the gene cause defects in one of several subunits of Type IV collagen. Accumulation of collagen types V and VI, with subsequent abnormalities in the permeability and sclerosis of the kidney, leads to renal failure. Renal failure causes severe bone disease since the kidney processes vitamin D, which is necessary for calcium absorption from the intestine. Therefore, in a patient with chronic renal disease, vitamin D is not produced, resulting in a decrease in intestinal absorption of calcium and subsequent lower serum calcium levels. Furthermore, the decreased phosphate excretion by the kidney leads to elevation of plasma phosphate, which increases the amounts of parathyroid hormone required to move calcium from bone (secondary hyperparathyroidism) to maintain plasma calcium at a constant level and preserve an appropriate calcium-phosphorous ratio. We have described AS, reviewed the pathogenesis and presented an interesting extreme case with numerous craniofacial manifestations.