In this X-linked disorder affected males are usually symptomless until the end of the first decade when severe pain in the extremities begins to occur. Angiokeratoma appears at about the same time as clusters of dark-red lesions around the genitals, buttocks, back and thighs. Later the painful crises subside but the patients succumb to renal and cardiovascular disease, with death in the forties or fifties. Eye changes are seen first as corneal haziness and later as whorls radiating from the centre of the cornea to the periphery. Many heterozygous female carriers of the disease show some of the symptoms seen in affected males, and a few have severe problems including renal failure. Examination for corneal opacities is a useful investigation in suspected carriers for whom biochemical results have been inconclusive.
Enzyme Deficiency ofa-Galactosidase A is the primary defect.