Department of Dermatology, National Reference Centre for Rare Skin Disorders, CHU de Bordeaux, Bordeaux, France.
Dermatology. 2011;222(4):336-41. doi: 10.1159/000328408. Epub 2011 Jun 23.
Atopic dermatitis (AD) is significantly associated with keratoconus (KC). An inherited component for KC has been suggested. Filaggrin (FLG) mutations are a strong genetic risk factor for AD. Since filaggrin is also expressed in the corneal epithelium, we hypothesized a common aetiology for ichthyosis vulgaris (IV), AD and KC.
We examined the prevalence of AD and IV in a KC population. We also studied the expression of filaggrin in normal and KC cornea and analysed 2 prevalent loss-of-function FLG alleles (R501X and 2282del4) in a KC population. Finally we examined whether the population with KC and FLG mutations had specific clinical characteristics.
Of 89 KC patients, 38 had current or a history of AD and/or IV. Five patients were carriers of at least 1 FLG mutant allele and had a clinical diagnosis of AD and IV with a severer KC.
The low frequency of FLG mutations is surprising since 42.7% of our KC population had AD associated or not with IV; the expected frequency would have been 12-15%, based on our previous studies. Further studies are required to look at other possible FLG mutations or other candidate genes.
特应性皮炎（AD）与圆锥角膜（KC）显著相关。已经提出 KC 具有遗传成分。丝聚蛋白（FLG）突变是 AD 的一个强烈遗传风险因素。由于丝聚蛋白也在角膜上皮中表达，我们假设寻常型鱼鳞病（IV）、AD 和 KC 具有共同的发病机制。
我们检查了 KC 人群中 AD 和 IV 的患病率。我们还研究了正常和 KC 角膜中丝聚蛋白的表达，并在 KC 人群中分析了 2 个常见的功能丧失 FLG 等位基因（R501X 和 2282del4）。最后，我们检查了是否具有 KC 和 FLG 突变的人群具有特定的临床特征。
在 89 名 KC 患者中，38 名患者有或有 AD 和/或 IV 的病史。5 名患者至少携带 1 个 FLG 突变等位基因，具有 AD 和 IV 的临床诊断，且 KC 更为严重。
FLG 突变的低频率令人惊讶，因为我们 KC 人群中有 42.7%的患者伴有或不伴有 AD 相关的 IV；根据我们之前的研究，预期频率应为 12-15%。需要进一步研究以寻找其他可能的 FLG 突变或其他候选基因。
