Acatalasia  is an autosomal recessive peroxisomal disorder caused by absent or very low levels of the enzyme catalase. Catalase breaks down hydrogen peroxide in cells into water and oxygen. Low levels of catalase can cause hydrogen peroxide to build up, causing damage to cells. Presentation
The disorder is relatively benign, although it causes an increased incidence of oral ulcers, and can under rare circumstances lead to gangrene. Symptoms primarily affect children. Genetic
Acatalasia is often the result of mutations in both copies of the CAT gene which codes for the enzyme catalase. There are multiple types of mutation that can cause this condition. Inheriting a single CAT mutation results in hypocatalasia, in which catalase levels are reduced, but still at functional levels. Diagnosis
This disorder is commonly diagnosed pouring hydrogen peroxide on the patients blood sample. Instead of a very bubbling reaction, blood turns brown-colored, which means the patient suffers from acatalasia. Management
Epidemiology
In parts of Japan, this condition has been found in approximately 1.4% of people. Researchers estimate that the condition occurs in 1 in 20,000 people in Hungary and Switzerland. History
In 1948, Dr. Shigeo Takahara (1908–1994), a Japanese otolaryngologist first reported this new disease. He had examined a patient with an oral ulcer. He had spread hydrogen peroxide on the diseased part, but oxygen was not generated due to the lack of catalase. See also
List of cutaneous conditions

References


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Trichorrhexis invaginata is a distinctive hair shaft abnormality that may occur sporadically, either in normal hair or with other hair shaft abnormalities, or regularly as a marker for Nethertons syndrome. : 638 : 766–7   The primary defect appears to be abnormal keratinization of the hair shaft in the keratogenous zone, allowing for intussusception of the fully keratinized and hard distal shaft into the incompletely keratinized and soft proximal portion of the shaft. : 638

Genetics
"Bamboo hair" is a  rare autosomal recessive genodermatosis characterized by congenital ichthyosiform erythroderma, trichorrhexis invaginata, and atopic diathesis with failure to thrive. Chronic skin inflammation results in scaling and exfoliation, predisposing these patients to life-threatening infections, sepsis, and dehydration. The Netherton syndrome Mendelian Inheritance in Man is inherited as an autosomal recessive disorder due to mutations of both copies of the SPINK5 gene (localized to band 5q31-32), which encodes the serine protease inhibitor LEKTI (lymphoepithelial Kazal-type-related inhibitor). LEKTI is expressed in epithelial and mucosal surfaces and in the thymus. Each SPINK5 mutation leads to a different length of LEKTI protein, resulting in genotype/phenotype correlations in cutaneous severity, susceptibility to atopic dermatitis, growth retardation, skin infection, increased stratum corneum protease activities, and elevated kallikrein levels in the stratum corneum.Trichorrhexis invaginata, or bamboo hair, is a hair shaft abnormality that occurs as a result of an intermittent keratinizing defect of the hair cortex.