Department of Pathology and Laboratory Medicine, Room C520, Medical Science Building, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, New Jersey 07103, USA.
Adv Exp Med Biol. 2010;685:106-10. doi: 10.1007/978-1-4419-6448-9_10.
Although the term, "trichothiodystrophy" (TTD) refers to the hair anomalies in this group of patients, this is a heterogeneous, multisystem disease in which any or every organ in the body may be affected. Neuroectodermal derived tissues are particularly likely to be involved. This term was introduced by Price et alin 1980 to designate patients with sulfur-deficient brittle hair, which they recognized as a marker for this complex disease and designated it as a "neuroectodermal symptom complex". Patients with TTD have brittle hair and nails (associated with reduced content ofcysteine-rich matrix proteins), ichthyotic skin and physical and mental growth retardation. Ichthyosis is usually apparent at birth but much less so after the first few weeks of life. Other frequently associated features include ocular cataracts, infections and maternal complications related to pregnancy. Atrophy of subcutaneous fat may also be present. TTD occurs in a pattern of inheritance consistent with an autosomal recessive condition. The disease is extremely heterogeneous in severity and extent, with some patients showing no neurological deficiency. Others show severe, multisystem disease. Many patients die at a young age, most commonly due to infectious disease. TTD is part of a more broadly defined group of diseases identified as IBIDS (ichthyosis, brittle hair, impaired intelligence, decreased fertility and short stature). Photosensitive cases are also identified as PIBIDS (photosensitivity with IBIDS). Cases without manifest ichthyosis are also identified as PBIDS. These syndromes defy rigorous definition because of clinical variation between patients. The original two cases were described by Tay in oriental siblings, whose parents were first cousins; thus the disease is also known as Tay syndrome. The hairs in patients with TTD have a distinctive, diagnostically useful appearance on polarized light microscopy consisting of alternating light and dark bands known as the "tiger tail" anomaly. Diagnosis may be confirmed by sulfur content analysis ofhair shafts, which shows decreased sulfur and cysteine content. Approximately half of patients with TTD have photosensitivity, which correlates with a nudeotide excision repair (NER) defect. These patients are designated as having trichothiodystrophy-photosensitive (TTDP). Non-photosensitivepatients are designated as having trichothiodystrophy-nonphotosensitive (TTDN). Skin cancer is very rare in sun-sensitive TTD.
尽管“毛发硫营养不良症”（TTD）一词是指这组患者的毛发异常，但这是一种异质性、多系统疾病，身体的任何或所有器官都可能受到影响。神经外胚层衍生组织特别容易受到影响。这个术语是由 Price 等人在 1980 年引入的，用于指定硫缺乏脆性毛发的患者，他们认识到这是这种复杂疾病的一个标志，并将其指定为“神经外胚层症状复合体”。TTD 患者的毛发和指甲脆弱（与富含半胱氨酸的基质蛋白含量减少有关）、鱼鳞癣皮肤以及身体和精神发育迟缓。鱼鳞癣通常在出生时就很明显，但在生命的头几周后就不太明显了。其他常伴有的特征包括眼部白内障、感染以及与妊娠有关的母体并发症。皮下脂肪萎缩也可能存在。TTD 以与常染色体隐性遗传一致的遗传模式发生。这种疾病在严重程度和范围上非常异质，一些患者没有神经缺陷，而另一些患者则表现出严重的多系统疾病。许多患者在年轻时死亡，最常见的原因是传染病。TTD 是一组被定义为 IBIDS（鱼鳞癣、脆性毛发、智力障碍、生育力降低和身材矮小）的疾病的一部分。光敏病例也被定义为 PIBIDS（具有 IBIDS 的光敏性）。无明显鱼鳞癣的病例也被定义为 PBIDS。由于患者之间的临床表现存在差异，这些综合征很难严格定义。最初的两个病例是由 Tay 在东方的兄弟姐妹中描述的，他们的父母是表亲；因此，这种疾病也被称为 Tay 综合征。TTD 患者的毛发在偏振光显微镜下具有独特的、具有诊断意义的外观，由称为“虎尾”异常的明暗交替带组成。通过毛发轴的硫含量分析可以确认诊断，结果显示硫和半胱氨酸含量减少。大约一半的 TTD 患者有光敏性，这与核苷酸切除修复（NER）缺陷相关。这些患者被指定为具有毛发硫营养不良症-光敏性（TTDP）。非光敏患者被指定为具有毛发硫营养不良症-非光敏性（TTDN）。在光敏性 TTD 中，皮肤癌非常罕见。
