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Sabinas brittle hair syndrome, also called Sabinas syndrome or brittle hair-mental deficit syndrome, is an autosomal recessive congenital disorder affecting the integumentary system. ==Characteristics== Symptoms include brittle hair, mild mental retardation and nail dysplasia. The syndrome was first observed in Sabinas, a small community in northern Mexico. The principal biochemical features of the illness are reduced hair cystine levels, increased copper/zinc ratio, and presence of arginosuccinic acid in the blood and urine. The key finding is brittle hair with low sulfur content, but alternating dark and light bands under polarizing microscopy, trichoschisis, and absent or defective cuticle are additional important clues for the diagnosis of trichothiodystrophy. Review of literature reveals extensive associated findings in trichothiodystrophy. Amino acid analyses of control hair when compared with those of patients with the Sabinas syndrome showed very striking differences with regard to content of sulphur amino acids. As in previous descriptions of amino acid abnormalities in the trichorrhexis nodosa of arginosuccinicaciduria, there were increases in lysine, aspartic acid, alanine, leucine, isoleucine, and tyrosine. Trichothiodystrophy represents a central pathologic feature of a specific hair dysplasia associated with several disorders in organs derived from ectoderm and neuroectoderm. Trichothiodystrophy or TTD is a heterogeneous group of autosomal recessive disorders, characterized by abnormally sulfur deficient brittle hair and accompanied by ichthyosis and other manifestations. Patients with trichothiodystrophy should have a thorough evaluation for other associated manifestations, including investigation of photosensitivity and DNA repair defects. Because the disease appears to be inherited in an autosomal recessive pattern, detection of low-sulfur brittle hair syndrome is also important for genetic counseling. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sabinas brittle hair syndrome」の詳細全文を読む スポンサード リンク
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