Patey-Mariaud de Serre Natacha, Noël Laure-Hélène
Service d'anatomie pathologique et tumorothèque, hôpital Necker-Enfants malades, université Paris René-Descartes, 149 rue de Sèvres, 75743 Paris cedex 15, France.
Ann Pathol. 2008 Jun;28(3):182-6. doi: 10.1016/j.annpat.2008.06.002. Epub 2008 Jul 21.
We describe a simple procedure to use skin biopsies for the diagnosis of Alport syndrome. The technique is based on the co-detection of alpha5 and alpha2 chains of collagen IV along the basal lamina of epidermis through an immunfluorescence technique. Eighty-five per cent of the cases of Alport syndrome are due to a mutation in the gene COL4A5, located on chromosome X, encoding the alpha5 chain of collagen IV. In this situation, the tissue expression of alpha5 chain is abnormal; in males, the absence of expression of alpha5 chain is pathognomonic for Alport syndrome; in females, the expression of alpha5 chain may be discontinuous because of X inactivation. The alpha2 chain is used as a positive control. We have studied skin biopsies from 55 patients (35 females, 20 males) with a suspicion of Alport syndrome, along with five controls. Immunofluorescence was performed on frozen tissue samples; for lecture, epifluorescence and confocal microscopy were compared. In controls, both chains were co-detected. In nine males out of 20, the expression of alpha5 was undetectable; it was preserved in the remaining cases. In female patients, the expression was discontinuous in 16 cases and undetectable in one. There was no difference in sensitivity between the two microscopic techniques. The co-detection of alpha5 and alpha2 chains of collagen IV in frozen skin biopsies is therefore proposed as a simple technique to diagnose Alport syndrome, but requires a good knowledge of the conditions of interpretation.
我们描述了一种利用皮肤活检诊断阿尔波特综合征的简单方法。该技术基于通过免疫荧光技术在表皮基底层共同检测IV型胶原的α5和α2链。85%的阿尔波特综合征病例是由位于X染色体上编码IV型胶原α5链的COL4A5基因突变引起的。在这种情况下，α5链的组织表达异常；在男性中，α5链表达缺失是阿尔波特综合征的特征性表现；在女性中，由于X染色体失活，α5链的表达可能不连续。α2链用作阳性对照。我们研究了55例疑似阿尔波特综合征患者（35名女性，20名男性）的皮肤活检样本以及5个对照样本。对冷冻组织样本进行免疫荧光检测；为了便于说明，比较了落射荧光显微镜和共聚焦显微镜。在对照样本中，两条链均被共同检测到。在20名男性中有9名未检测到α5的表达；其余病例中α5表达保留。在女性患者中，16例表达不连续，1例未检测到表达。两种显微镜技术在敏感性上没有差异。因此，建议在冷冻皮肤活检中共同检测IV型胶原的α5和α2链作为诊断阿尔波特综合征的一种简单技术，但需要对解读条件有充分了解。
