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October 1962

Trichorrhexis Nodosa and Amino Acid Metabolism

Author Affiliations

Miami, Fla.

Arch Dermatol. 1962;86(4):391. doi:10.1001/archderm.1962.01590100005001

Screening of mentally defective children by paper chromatographic estimation of blood and urine amino acids has unearthed a new disease termed argininosuccinic aciduria.1 A summary of the 3 cases discovered to date2 reveals, in all, the presence of the classic but rare morphologic disturbance of scalp hairs—trichorrhexis nodosa. This diagnosis was confirmed by Dr. A. Jarrett, of London, who noted an abnormal red fluorescence of the fractured hair ends when stained with acridine orange.3

The biochemical defect in argininosuccinic aciduria is expressed in the accumulation and excretion of large amounts of argininosuccinic acid, an intermediate in the Krebs-Henseleit cycle of urea production in mammals. Apparently the condensing enzyme of the over-all arginine synthetase system is active but the body is unable to split the product into arginine and fumarate. Preliminary observations4 have indicated that this cleavage enzyme is normally absent (at least under certain in vitro