Acatalasia

Acatalasia is an autosomal recessive peroxisomal disorder caused by absent or very low levels of the enzyme catalase, which normally breaks down hydrogen peroxide in cells into water and oxygen. Where catalase is lacking, hydrogen peroxide can build up and damage cells. The disorder is relatively benign, but it raises the incidence of oral ulcers and can, rarely, lead to gangrene, with symptoms mainly affecting children. It usually results from mutations in both copies of the CAT gene, while inheriting a single mutation produces hypocatalasia, in which catalase remains at a functional level. A classic bedside test pours hydrogen peroxide on a blood sample: instead of vigorous bubbling the blood turns brown. In parts of Japan about 1.4 percent of people were found to be heterozygous carriers, and researchers estimate roughly one case in 20,000 in Hungary and Switzerland. The Japanese otolaryngologist Shigeo Takahara first reported the disease in 1948 after hydrogen peroxide failed to release oxygen on a patient's oral ulcer. The atlas records what is described in the literature and gives no medical advice.